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Digital Poster - Wednesday
Weekend and Oral

Digital Poster (no CME credit)

Monday Digital Poster Tuesday Digital Poster Thursday Digital Poster

Wednesday Digital Poster (No CME Credit)

Diffusion

08:15
3339 - 3508
09:15
3509 - 3656

MR Value

09:15
3657 - 3680

fMRI

13:30
3681 - 3804

Interventional MRI

13:30
3805 - 3854

fMRI

14:30
3855 - 3954

Contrast Mechanisms

14:30
3955 - 4029

MR Safety

15:45
4151 - 4200

Spectroscopy & Non-Proton MR

16:45
4201 - 4254

Molecular Imaging

16:45
4255 - 4375

Diffusion MRI: Image Reconstruction

Exhibition Hall
Wednesday 8:15 - 9:15
 Diffusion

3339
Computer 1
Improved MUSSELS Reconstruction for High Resolution Diffusion Weighted Imaging Using Fast Iterative Re-weighted Least Squares Algorithm
Merry Mani1, Hemant Kumar Aggarwal1, Vincent Magnotta1, and Mathews Jacob1

1University of Iowa, Iowa City, IA, United States

Multi-shot diffusion-weighted imaging reconstructions are challenged by the inter-shot phase inconsistency that exists between the data from different shots. The MUSSELS algorithm enabled the direct reconstruction of the multi-shot k-space data by posing it as a low-rank based matrix recovery problem. The iterative algorithm has been shown to successfully recover the missing k-space samples in accelerated and non-accelerated acquisitions. However, the reconstruction time increases as the number of shots\acceleration increases. We propose a new formulation based on iterative re-weighted least squares that increase the computational efficiency of the matrix completion by several folds to speed up the recovery of multi-shot data.

3340
Computer 2
Simultaneous Multi-Slice Diffusion MR Reconstruction using Coil-Combined Split Slice-GRAPPA
Kazem Hashemizadeh1, Rong-Rong Chen1, Edward V. R. DiBella1,2, Leslie Ying3, and Ganesh Adluru2

1ECE, University of Utah, SALT LAKE CITY, UT, United States, 2Radiology and Imaging Science, University of Utah, SALT LAKE CITY, UT, United States, 3Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, United States

Simultaneous multi-slice (SMS) acquisition  accelerates diffusion MR imaging by acquiring multiple slices simultaneously. In this work, we propose a new method, termed coil-combined split slice-GRAPPA (CC-SSG), to improve the quality of SMS diffusion imaging reconstruction.  By optimizing  split-slice-GRAPPA (SSG) kernels specifically for coil combining, our approach allows for a better trade-off for suppressing  inter-slice and intra-slice leakages and  minimizes the mean-square-error (MSE) of coil-combined images. The proposed CC-SSG method improves the estimation of diffusion tensor imaging (DTI) parameters over existing methods. 

3341
Computer 3
Joint-diffusion GRAPPA: enabling higher acceleration rates in dMRI by exploiting joint information from the k- and q-space
Gabriel Ramos-Llordén1, Santiago Aja-Fernández2, Congyu Liao3, Kawin Setsompop3, and Yogesh Rathi1

1Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 2Laboratorio de Procesado de Imagen, Universidad de Valladolid, Valladolid, Spain, 3Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States

In this work, we generalize conventional GRAPPA-based dMRI reconstruction by exploiting joint information from the k-and q-space simultaneously. Higher acceleration in-plane rates than those commonly reported may be achieved when the missing k-space lines are learned using all information available in the whole k-space data set, that is,  considering multi-coil channel information as well as the k-space data probed at different q-space points.

Our novel method, joint-diffusion GRAPPA, is validated with in-vivo multi-slice dMRI data, where we show it always outperforms conventional GRAPPA in terms of image quality, and works reasonably well for regimes where conventional GRAPPA results in significant noise penalty ($$$R_{in-plane}$$$ > 3 ).  


3342
Computer 4
Use of self-navigation to enable efficient 3D DWI SE-EPI multislab multiband imaging
Steen Moeller1, Sudhir Ramanna1, Edward Auerbach1, Pramod Pisharady1, Christophe Lenglet1, Mehmet Akcakaya1,2, and Kamil Ugurbil1

1University of Minnesota, Minneapolis, MN, United States, 2Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States

A method is proposed for self-navigation of DWI 3D multislab multiband SE-EPI, to enable whole brain high-resolution imaging, with optimal imaging TR for higher SNR efficiency. Data for high b-value (b=3k s/mm2) and 1mm3 resolution is presented.

3343
Computer 5
Acceleration of 3D diffusion MRI using a kernel low rank compressed method
Chaoyi Zhang1, Tanzil Mahmud Arefin2, Ukash Nakarmi3, Hongyu Li1, Dong Liang4, Jiangyang Zhang2, and Leslie Ying1,5

1Electrical Engineering, University at Buffalo, State University of New York, buffalo, NY, United States, 2Radiology, New York University School of Medicine, New York City, NY, United States, 3Radiology & Electrical Engineering, Stanford University, Stanford, CA, United States, 4Paul C Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Shenzhen, China, 5Biomedical Engineering, University at Buffalo,State University of New York, buffalo, NY, United States

Diffusion MRI has showed great potential in probing tissue microstructure and brain structural connectivity. However, high-resolution diffusion MRI with multiple direction is limited by the lengthy scan time. In this abstract, we apply a kernel low rank model to accelerate diffusion imaging by undersampling the k-space. This method is validated using high-resolution mouse brain datasets. Compared with the conventional compressed sensing method, the proposed method demonstrate more accurate mean diffusivity, fractional anisotropy and fiber orientation distribution estimates with acceleration factors up to 8.

3344
Computer 6
Deep Learned Diffusion Tensor Imaging
Hongyu Li1, Chaoyi Zhang1, Zifei Liang2, Dong Liang3, Bowen Shen4, Yulin Ge2, Jiangyang Zhang2, Ruiying Liu1, Peizhou Huang1, Sunil Kumar Gaire1, Xiaoliang Zhang1, and Leslie Ying1

1Department of Biomedical Engineering, Department of Electrical Engineering, The State University of New York at Buffalo, Buffalo, NY, United States, 2Radiology, New York University School of Medicine, New York City, NY, United States, 3Paul C. Lauterbur Research Center for Biomedical Imaging, Medical AI research center, SIAT, CAS, Shenzhen, China, 4Department of Computer Science, Virginia Tech, Blacksburg, VA, United States

Diffusion tensor imaging typically requires acquisition of a large number of diffusion weighted images (DWI) for accurate fitting of the tensor model due to the issue of low SNR. This abstract presents a deep learning method to generate FA color map showing the primary diffusion directions from very few DWIs. The method uses deep convolutional neural networks to learn the nonlinear relationship between the DWIs and the FA color maps, bypassing the conventional DTI models. Experimental results show that the proposed method is able to generate FA color maps from only 6 DWIs with quality comparable to results from 270 DWIs using conventional tensor fitting.

3345
Computer 7
Self-navigated Half-Fourier Multi-shot Echo-planar DWI Reconstructions for Brain Imaging
Malte Steinhoff1, Kay Nehrke2, Peter Börnert2,3, and Alfred Mertins1

1Institute for Signal Processing, University of Lübeck, Lübeck, Germany, 2Philips Research Hamburg, Hamburg, Germany, 3Dept. Radiology, LUMC, Leiden, Netherlands

EPI trajectories using Half-Fourier achieve shorter echo times and therefore higher SNR, which is especially desirable in low-SNR applications like diffusion-weighted MRI. For the same reason, methods enabling phase-corrected image recovery for multi-shot diffusion acquisitions have been intensively studied for both spiral and EPI trajectories. In this work, two algorithms are presented comprising both half-Fourier and the multi-shot same-magnitude constraints to exploit the advantages of both techniques. The algorithms are shown to robustly recover interleaved half-Fourier datasets from in-vivo brain acquisitions.

3346
Computer 8
Multi-shot Diffusion EPI Reconstruction with Iterative Rigid Motion-correction and Motion-induced Phase-correction for Brain Imaging
Malte Steinhoff1, Kay Nehrke2, Alfred Mertins1, and Peter Börnert2,3

1Institute for Signal Processing, University of Lübeck, Lübeck, Germany, 2Philips Research Hamburg, Hamburg, Germany, 3Dept. Radiology, LUMC, Leiden, Netherlands

Multi-shot diffusion-weighted imaging offers increased SNR and higher resolution, but makes the acquisition vulnerable to shot-specific phase variations and macroscopic inter-shot motion. A wide range of iterative phase-corrected reconstruction schemes have been proposed to overcome the inter-shot phase inconsistencies, but robust motion estimation is still challenging due to the inherently low SNR of DWI. This work moves forward from initial one-time rigid motion estimation to an alternating optimization balancing the joint image, phase and motion estimation. A novel multi-shot echo-planar diffusion algorithm with iterative motion and phase correction is presented in simulations and in-vivo.

3347
Computer 9
Accelerating Iterative SENSE-based Algorithms for Cartesian Trajectories using the Point Spread Function and Coil Compression
Malte Steinhoff1, Kay Nehrke2, Alfred Mertins1, and Peter Börnert2,3

1Institute for Signal Processing, University of Lübeck, Lübeck, Germany, 2Philips Research Hamburg, Hamburg, Germany, 3Dept. Radiology, LUMC, Leiden, Netherlands

For multi-shot diffusion-weighted imaging, iterative SENSE-based algorithms like POCSMUSE are boosting SNR allowing for higher image resolution. These advantages are achieved at the cost of higher computational load, thereby narrowing the clinical use case. The Cartesian implementation of such SENSE algorithms iteratively involves time-consuming 1D-Fast Fourier Transforms. In this abstract, the well-known point spread function for regular Cartesian undersampling is exploited to accelerate gradient- and projection-based SENSE updates. Accelerations of approximately 45% were achieved. Furthermore, coil compression is evaluated for these algorithms.

3348
Computer 10
Super-Resolution Diffusion Imaging using Deep Learning: A Feasibility Study
Nahla M H Elsaid1,2 and Yu-Chien Wu1,2

1Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indiana University, Indianapolis, IN, United States, 2Indiana Alzheimer Disease Center, Indianapolis, IN, United States

In this study, we present and validate the efficacy of using a state-of-the-art deep-learning method to achieve submillimeter high-resolution diffusion-weighted (DW) images. The 2D-based deep-learning method was validated by comparing diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) of the deep-learning high-resolution images and the ground-truth.

3349
Computer 11
Super-Resolution Hybrid Diffusion Imaging (SR-HYDI)
Nahla M H Elsaid1,2, Pierrick Coupé3,4, and Yu-Chien Wu1,2

1Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indiana University, Indianapolis, IN, United States, 2Indiana Alzheimer Disease Center, Indianapolis, IN, United States, 3University of Bordeaux, LaBRI, UMR 5800, PICTURA, F-33400 Talence, France, 4CNRS, LaBRI, UMR 5800, PICTURA, F-33400 Talence, France

In this study, we present and validate an efficient pipeline for submillimeter super-resolution hybrid diffusion imaging (SR-HYDI). The pipeline employs a collaborative patch-based super-resolution interpolation approach, which uses self-similarity to drive the reconstruction of diffusion-weighted images. The FA and MD generated from the proposed pipeline are compared against the ground-truth for validation.

3350
Computer 12
Complex-valued diffusion MRI data processing: Application to neural soma imaging
Enrico Kaden1, Umesh S Rudrapatna2, Noemi G Gyori1,3, Uran Ferizi4, Chris A Clark3, Derek K Jones2,5, and Daniel C Alexander1

1Centre for Medical Image Computing, University College London, London, United Kingdom, 2Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom, 3Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 4Department of Radiology, New York University School of Medicine, New York, NY, United States, 5School of Psychology, Australian Catholic University, Melbourne, Australia

Microscopic diffusion anisotropy imaging requires averaging the diffusion signal over the gradient directions to regress out the unwanted effects of the fibre orientation distribution. However, Rician noise biases the mean signal calculations especially in the high b-value regime and subsequently the estimation of microstructural tissue features. In this work we develop new data processing methods using complex-valued MRI data that remove the background phase and hence retain the Gaussian characteristics of the signal noise, which is demonstrated in neural soma imaging, a novel application of the Spherical Mean Technique (SMT).

3351
Computer 13
Giving up the ghost: a systematic comparison of 2D phase correction algorithms in multi-shell high angular diffusion weighted imaging
Elizabeth Powell1,2, Torben Schneider3, Marco Battiston2, Matthew Clemence3, Ahmed Toosy2, Jonathan Clayden4, and Claudia A.M. Wheeler-Kingshott2,5,6

1Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom, 3Philips Healthcare UK, Guildford, Surrey, United Kingdom, 4Developmental Imaging and Biophysics Section, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 5Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy, 6Brain MRI 3T Research Center, IRCCS Mondino Foundation, Pavia, Italy

The echo planar imaging (EPI) Nyquist ghost often requires complex 2D phase error corrections in order to be robustly removed. Several methods exist but have not yet been systematically evaluated in high b-value diffusion-weighted (DW) EPI, where lower signal-to-noise ratios may affect the phase error estimation. We explore here the influence of different 2D phase-error corrected reconstruction methods on quantitative parameters derived from DW-EPI, and demonstrate that errors in parameter estimations relating to the Nyquist ghost can persist even after 2D phase-error correction.

3352
Computer 14
Whole-brain DTI at 860 μm isotropic resolution in 10 minutes on a commercial 3T Scanner
Yunsong Liu1, Congyu Liao2, Kawin Setsompop2, and Justin P. Haldar1

1Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, United States, 2Martinos Center for Biomedical Imaging, Charlestown, MA, United States

We describe an acquisition and reconstruction methodology that enables in vivo human diffusion tensor imaging with whole-brain coverage and 860$$$\mu$$$m isotropic spatial resolution, all within a 10 minute acquisition window on a commercial 3T scanner.  Our approach is enabled by combining the gSlider-SMS acquisition approach (which uses simultaneous multi-slab acquisition for increased spatial coverage, combined with highly-efficient RF slab-encoding to achieve high spatial resolution) with an SNR-enhancing joint reconstruction approach that mitigates the noise associated with high-resolution acquisition.

3353
Computer 15
Estimation and Correction of Image Phase in diffusion weighted MRI using Deep Learning
Carolin Hecking-Veltman1,2, Carolin M. Pirkl1,2, Jonathan Dannenberg2,3, Rolf F. Schulte2, Tim Sprenger4, Bjoern H. Menze1, and Marion I. Menzel2,3

1Computer Science, Technical University Munich, Munich, Germany, 2GE Healthcare, Munich, Germany, 3Physics, Technical University Munich, Munich, Germany, 4MR Applied Science Laboratory Europe, GE Healthcare, Stockholm, Sweden

The phase of diffusion weighted MR images (DWI) is regularly discarded in clinical application although it might contain valuable information, as it is composed of phase contributions due to rigid motion, eddy currents and brain pulsation among others.

In this work we take advantage of a neural network to separate the different phase components in individual DWI phase images. This enables estimating the amount of brain pulsation from DWI and modelling brain pulsation. The gained information may be used for phase correction, which eventually will allow using real-valued DWI (instead of magnitude DWI) to eliminate the Rician bias.  


3354
Computer 16
Nyquist Ghost Correction of High-Resolution SMS Breast DWI with Ghost/Object Minimization
Jessica A McKay1,2, Steen Moeller2,3, Sudhir Ramanna2,3, An L Church3, Michael T Nelson3, Edward J Auerbach2,3, Kamil Ugurbil2,3, and Patrick J Bolan2,3

1Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 3Radiology, University of Minnesota, Minneapolis, MN, United States

A recent novel approach to acquire high-resolution breast DWI uses a simultaneous multi-slice (SMS) SE-EPI sagittal acquisition. In EPI, Nyquist ghosts are typically corrected using a 3-line navigator, which often fails in SMS SE-EPI breast DWI due to low SNR, insufficient fat suppression, and larger B0 inhomogeneity. In this work we compare a referenceless ghost correction method, called Ghost/Object minimization, with the standard 3-line navigator in high-resolution breast DWI. Ghost/Object provides more reliable 1st-order ghost correction in a dynamic and slice-specific way, which improves image quality and reduces bias in ADC values compared to the standard correction.

3355
Computer 17
Pseudo-3D Diffusion-Weighted Imaging of the Brain using Echo Planar Imaging with Compressed SENSE (EPICS)
Kosuke Morita1, Masami Yoneyama2, Takeshi Nakaura3, Seitaro Oda3, Masahiro Hatemura1, and Yasuyuki Yamashita3

1Radiology, Kumamoto University, Kumamoto-shi, Japan, 2Philips Japan, Tokyo, Japan, 3Diagnostic Radiology, Kumamoto University, Kumamoto-shi, Japan

We attempted to obtain brain high-resolution pseudo-3D (2D multi-slice acquisition with very thin slice thickness) diffusion-weighted echo planar imaging (DW-EPI) using a hybrid compressed sensing and sensitivity encoding (Compressed SENSE) framework (EPICS). pseudo-3D-DWI with EPICS achieved high-resolution (1.15 mm3) isotropic DWI within clinically feasible scan time. Furthermore, EPICS clearly improved the accuracy and robustness of ADC values in high b-value brain DWI with pseudo-3D acquisition without any penalty for scan parameters.

3356
Computer 18
Fast reconstruction of fractional anisotropy with two-dimensional principal component analysis based recognition
Fangrong Zong1, Zihao Zhang2,3, Qingle Kong2,4, Jing An5, Yan Zhuo2,3, and Xiaoliang Zhang6,7

1The Key Laboratory for Interdisciplinary Research, Institute of Biophysics, China Academy of Sciences, Beijing, China, 2State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 3The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, Beijing, China, 4University of Chinese Academy of Sciences, Beijing, China, 5Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 6Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 7UCSF/UC Berkeley Joint Graduate Group in Bioengineering San Francisco, San Francisco, CA, United States

Reducing the acquisition time for obtaining fractional anisotropy (FA) is of paramount importance to investigate cerebral microstructures and morphologies non-invasively. This is the first time to introduce the two-dimensional principal component analysis recognition reconstruction (i.e. 2D-PCA-RR) in recovering highly under-sampled FA maps with 5-fold acceleration of data acquisition. An in-house data processing procedure is implemented to optimize signal-to-noise ratio and construct a distortion-free database. Our results from two different under-sampling patterns show a superior performance gain from the 2D-PCA-RR algorithm as compared to conventional reconstruction methods.

3357
Computer 19
Acquisition and processing strategy for obtaining high quality, distortion free diffusion MRI of the brainstem and cervical spine
Neda Sadeghi1, Joelle E. Sarlls2, Jessica Jordan3, Flavia Facio4, Elizabeth B. Hutchinson1,5, M. Okan Irfanoglu1, Amritha Nayak1,5, Laura Reyes1,5, Shruti Japee3, Irini Manoli4, Carlo Pierpaoli1, and Moebius Syndrome Research Consortium6,7,8

1Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD, United States, 2NIH MRI Research Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, United States, 3Laboratory of Brain and Cognition, National Institute of Mental Health, NIH, Bethesda, MD, United States, 4Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, United States, 5Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States, 6NIH, Bethesda, MD, United States, 7Boston Children's Hospital and Harvard Medical School, Boston, MA, United States, 8Icahn School of Medicine at Mount Sinai, New York City, NY, United States

Despite its clear clinical and research usefulness, high quality in-vivo diffusion MRI imaging of the brainstem and the cervical spine has been challenging due to susceptibility-induced distortions and ghosting in echo planar images (EPI). In this study, we propose an acquisition and data processing strategy that can be carried out on clinical scanners with commonly available EPI sequences with good resolution and in a reasonable scan time (less than 30 minutes). We apply this acquisition strategy to the study of pyramidal decussation in subjects with Moebius syndrome and mirror movements.

3358
Computer 20
Accelerating Diffusion MRI via Slice Undersampling and Deep-Learning Reconstruction
Yoonmi Hong1, Geng Chen1, Pew-Thian Yap1, and Dinggang Shen1

1Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

In this abstract, we present a proof-of-concept method for effective diffusion MRI reconstruction from slice-undersampled data. Instead of acquiring full diffusion-weighted (DW) image volumes, only a subsample of equally-spaced slices are acquired. We show that the complementary information from DW volumes corresponding to different diffusion wavevectors can be harnessed using graph convolutional neural networks for reconstruction of the full DW volumes.

3359
Computer 21
Deep learning for DSI parameter map generation without image pre-processing
Eric Kenneth Gibbons1, Kyler K. Hodgson2, Ganesh Adluru1, and Edward VR DiBella1

1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Bioengineering, University of Utah, Salt Lake City, UT, United States

Recent advances in diffusion spectrum imaging (DSI) have reduced scan time considerably.  Through the use of deep learning, DSI parameter maps (NODDI, GFA, etc.) can be generated with only a fraction of the number of q-space samples compared to conventional acquisition strategies.  However, image pre-processing prior to the deep learning parameter map generation step is a computational bottleneck. This abstract explores if this bottleneck can be bypassed entirely and use images straight from the scanner as CNN inputs.  We show that the image pre-processing is not necessary to generate NODDI and GFA parameter maps--thereby avoiding the image processing computation time.

3360
Computer 22
Phase-Error-Free Multi-shot 3D DWI using Filtered Back Projection Reconstruction
Hai Luo1, Gaojie Zhu1, Xiang Zhou1, Chao Wang1, Bei Lv1, Xia Liu1, and Ziyue Wu1,2

1AllTech Medical Systems, Chengdu, China, 2Alltech Medical System America, Solon, OH, United States

Conventional multi-shot DWI is known to suffer from inter-shot phase inconsistencies due to motion and hardware imperfections. In this work, we present a new approach for phase-error-free diffusion imaging by using multi-shot Paddlewheel-shaped EPI acquisition and filtered back projection (FBP) Reconstruction. The necessity of inter-shot phase correction is removed due to the magnitude-only nature of FBP. Reduced FOV excitation scheme is incorporated to reduce scan time and artifacts. Exemplary results of head and prostate DWI are demonstrated to show the efficacy of the proposed methods.

3361
Computer 23
Imaging Cortical Columns in Gray Matter with Sub-Millimeter isotropic DTI
Iain P Bruce1, Christopher Petty1, and Allen W Song1

1Duke University Medical Center, Durham, NC, United States

The microarchitecture in gray matter of the human brain is comprised of short (<3 mm) cortical columns that traverse six cortical layers. To most accurately delineate these columns in-vivo, it is essential to achieve isotropic spatial resolutions on the order of 0.8 mm or less. In this study, we present a means of acquiring diffusion tensor imaging data with ultrahigh spatial resolution to effectively characterize the complex architecture of gray matter.

3362
Computer 24
High-resolution DWI for breast by using multi-band sense technique
Lingyan Kong1, Ning Ding1, Zhengyu Jin1, Dong Liu1, Zhizheng Zhuo2, and Huadan Xue1

1Radiology Department, Peking Union Medical College Hospital, Beijing, China, 2Philips Healthcare, Beijing, China

Two challenges in clinical MRI are the slow image acquisition time and low image resolution compared to other clinical imaging technique such as CT.  The purpose of this study is to improve the image quality of diffusion weighted imaging (DWI) for clinical breast examination within a limited scanning time by using multi-band sense technique.

3363
Computer 25
Rapid and Accurate NODDI Parameter Estimation with the Spherical Mean Technique
Ryan P Cabeen1, Farshid Sepehrband1, and Arthur W Toga1

1Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, Los Angeles, CA, United States

Neurite orientation dispersion and density imaging (NODDI) is a widely used tool for modeling microstructure using diffusion MRI, but its computational cost can be prohibitively expensive.  This work investigates the efficacy of integrating the spherical mean technique (SMT) into a non-linear optimization framework to improve NODDI parameter estimation.  Through quantitative simulation, comparative, and reliability analyses, we found that integrating SMT into more traditional non-linear optimization enables rapid, accurate, and reliable estimation of neurite density and dispersion compared to other approaches.


Diffusion MRI: Fiber Orientations & Tracking

Exhibition Hall
Wednesday 8:15 - 9:15
 Diffusion

3364
Computer 26
Assessment of the reproducibility of structural brain networks derived using different edge-weighting strategies
Eirini Messaritaki1, Stavros I Dimitriadis1,2, and Derek K Jones2,3

1Medicine, Cardiff University, Cardiff, United Kingdom, 2Psychology, Cardiff University, Cardiff, United Kingdom, 3Psychology, Australian Catholic University, Melbourne, Australia

Structural brain networks derived from diffusion Magnetic Resonance Imaging data can use various tract metrics to weigh the network edges. In this work we use the Human Connectome Project test-retest diffusion MRI data to assess the reproducibility of structural brain networks, their edges and their graph-theoretical measures derived using different edge-weighting strategies.

3365
Computer 27
White matter parcellation test-retest reproducibility of diffusion MRI tractography fiber clustering
Fan Zhang1, Ye Wu1, Isaiah Norton1, Yogesh Rathi1, Alexandra J. Golby1, and Lauren J. O'Donnell1

1Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States

Fiber clustering is a popular strategy for automated white matter parcellation using diffusion MRI tractography. However, there has been no investigation to assess fiber clustering parcellation test-retest reproducibility, i.e. whether white matter parcellations could be reliably reproduced in repeated scans. This work presents the first study of fiber clustering white matter parcellation test-retest reproducibility. We perform evaluation on a large test-retest dataset, including a total of 255 subjects from multiple independently acquired datasets. Our results in general indicate that the fiber clustering method produced more reproducible white matter parcellations than a popular cortical-parcellation-based method.

3366
Computer 28
Connectome analysis of world class gymnasts using probabilistic multi-shell multi-tissue constrained spherical deconvolution tracking
Wataru Uchida1,2, Koji Kamagata1, Christina Andica1, Hiroyuki Tomita3, Hidefumi Waki3, Mana Kuramochi1,2, Yuki Takenaka1,2, Akifumi Hagiwara1,4, Makoto Fukuo3, Kouhei Tsuruta1, Issei Fukuaga1, Syo Murata1, Mutsumi Harada3, Shigeki Aoki1, and Hisashi Naito3

1Department of Radiology, Juntendo University Graduate School of Medicine, Tokyo, Japan, 2Department of Radiological Sciences, Tokyo Metropolitan University Graduate School of Human Health Sciences, Tokyo, Japan, 3Department of Sports Science, Juntendo University Graduate School of Medicine, Tokyo, Japan, 4Department of Radiology, University of Tokyo Graduate School of Medicine, Tokyo, Japan

We analyzed the brain anatomical networks between world-class gymnasts and controls using probabilistic Multi-shell, Multi-tissue Constrained Spherical Deconvolution tracking method. Our results showed higher neural connectivities in gymnasts in the brain areas related to motor activity and visual perception. In addition, a positive correlation between difficulty-score (D-score) and brain connectivity was also in the brain areas including auditory, limbic, associative and visual area. In conclusion, our findings can be useful for a better understanding of neural changes related to gymnastic skills.

3367
Computer 29
A novel connectomics metric for investigating the structural-functional relationship in the brain
Oren Civier1,2, Marion Sourty1,2, and Fernando Calamante1,2,3,4

1School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, Australia, 2Brain and Mind Centre, The University of Sydney, Sydney, Australia, 3Sydney Imaging, The University of Sydney, Sydney, Australia, 4Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia

We present a novel connectomics metric that quantifies the relationship between structural connectivity (SC) and functional connectivity (FC) in each connection in the brain. The metric is based on a biologically meaningful and quantitative measure of SC, followed by normalization of both modalities to a common scale. We demonstrated the utility of the metric in examining structural-functional relationships in pairs of homologous connections, detecting homologues that are dissimilar. The metric is more informative than using FC in isolation, and might provide insights into factors that contribute to FC beyond the strength of SC (e.g., indirect connections, organization of fibres).

3368
Computer 30
Bundle Analytics: a computational and statistical analyses framework for tractometric studies
Bramsh Qamar Chandio1, Jaroslaw Harezlak2, Serge Koudoro 1, David Reagan 3, and Eleftherios Garyfallidis1

1Intelligent Systems Engineering, Indiana University Bloomington, Bloomington, IN, United States, 2School of Public Health, Indiana University Bloomington, Bloomington, IN, United States, 3Pervasive Technology Institute, Indiana University Bloomington, Bloomington, IN, United States

Bundle Analytics promises fast, robust, and flexible computational and statistical analyses for tractometric studies on clinical data. It uses information from both tractometry, and anatomy to analyze the extracted fiber bundles from challenging clinical datasets. It uses streamline-based efficient algorithms to register and extract fiber bundles from a tractogram, and applies linear mixed models in the extracted bundles to find significant differences at specific locations of the bundles across groups. Finally, the method does not require training, an important advantage over deep learning methods.

3369
Computer 31
Is it feasible to directly access the bundle’s specific myelin content, instead of averaging? A study with Microstructure Informed Tractography
Simona Schiavi1, Marco Pizzolato2, Mario Ocampo-Pineda1, Erick Canales-Rodriguez3,4, Jean-Philippe Thiran2,3, and Alessandro Daducci1

1Department of Computer Science, University of Verona, Verona, Italy, 2Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 3Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland, 4FIDMAG Germanes Hospitalàries Research Foundation, Sant Boi de Llobregat, Barcelona, Spain

Diffusion MRI connectometry is a widely used tool to investigate features of structural connectomes that reflect differences in white matter tracks integrity. It consists in averaging microstructural tissues properties (obtained from any voxel-wise map) along streamlines recovered with diffusion tractography. Nevertheless, the average of a microstructural measure is a weak information about an entire bundle. Using microstructure-informed tractography (COMMIT), we were able to simultaneously estimate fiber’s specific myelin water fraction, intra-axonal volume fraction, and g-ratio. We also computed new connectomes with bundles’ specific measures instead of the commonly used averages.

3370
Computer 32
Using HCP data to improve diffusion tractography in routine-quality data: Application to the virtual dissection of the SLF system
Chiara Maffei1 and Anastasia Yendiki2

1Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 2Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital and Harvard Medical School, SOMERVILLE, MA, United States

The development of scanners with ultra-high gradients, spearheaded by the Human Connectome Project, has led to dramatic improvements in the spatial, angular, and diffusion resolution that is feasible for in vivo diffusion MRI acquisitions. Here we show that global probabilistic tractography with anatomical priors can be trained on such data, which can only be acquired on a handful of Connectome scanners worldwide, and improve the accuracy of tractography in more widely available, routine-quality diffusion data. We apply this method to reconstruct the three subcomponents of the SLF and show its superior accuracy compared to a conventional multi-ROI approach.

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Reducing false-positive connections using hierarchical microstructure-informed tractography
Mario Ocampo-Pineda1, Simona Schiavi1, Matteo Frigo1,2, Muhamed Barakovic3, Gabriel Girard3,4, Maxime Descoteaux5,6, Jean-Philippe Thiran3,4, and Alessandro Daducci1,3,4

1Computer Science Department, University of Verona, Verona, Italy, 2Athena Project-Team, Inria Sophia-Antipolis Méditerranée, Université Côte d'Azur, Nice, France, 3Signal Processing Laboratory 5 (LTS5), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 4Radiology Department, University Hospital Center (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 5Sherbrooke Connectivity Imaging Laboratory (SCIL), University of Sherbrooke, Sherbrooke, QC, Canada, 6Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Science, Sherbrooke Molecular Imaging Center, Sherbrooke, QC, Canada

Tractography has proven particularly effective for studying non-invasively the neuronal architecture of the brain, but recent studies have showed that the high incidence of false-positives can significantly bias any connectivity analysis. Last year we presented a method that extended COMMIT framework to consider the prior knowledge that white matter fibers are organized in bundles. Inspired by this, here we propose another extension to further improve the quality of the tractography reconstructions. We introduce a novel regularization term based on the multilevel hierarchy organization of the human brain and we test the results on both synthetic phantom and in vivo data.

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TractEM: A fast protocol for Whole Brain Tractography
Roza G Bayrak1, Kurt G Schilling2, Jasmine Greer3, Colin B Hansen1, Justin A Blaber4, Christa M Greer3, Susan M Resnick5, Owen A Williams5, Lori L Beason-Held5, Baxter P Rogers2,6, and Bennett A Landman2,4

1Computer Science, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University Institue of Imaging Science, Nashville, TN, United States, 3Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 4Electrical Engineering, Vanderbilt University, Nashville, TN, United States, 5Laboratory of Behavioral Neuroscience, National Institue of Aging, National Institutes of Health, Baltimore, MD, United States, 6Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States

We introduce TractEM, a tractography-based whole-brain labeling protocol informed by the Eve Labeling [1] procedures from the single-subject Johns Hopkins white matter atlas [1, 2]. This project proposes to create a resource of manually labelled white matter atlases that is driven by state-of-the-art diffusion tractography, and can be manually created in less than 6 hours. We defined and tested the TractEM protocol on 61 tracts for 20 subjects, with multiple raters per subject, and show moderate to high reproducibility for most labels. TractEM should be a useful resource for generating target templates for automated labeling methods. 

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Structural anatomy of the executive control network – a high angular resolution diffusion MRI study
Kaikai Shen1,2,3, Thomas Welton3, Matt Lyon3, Jurgen Fripp1, Ralph Martins2, and Stuart M Grieve3,4

1Australian eHealth Research Centre, CSIRO, Brisbane, Australia, 2Department of Biomedical Sciences, Macquarie University, Sydney, Australia, 3Sydney Translational Imaging Laboratory, Heart Research Institute, University of Sydney, Sydney, Australia, 4Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia

In this abstract, our aim is to investigate the relationship between executive function and the underlying structures of the executive control network (ECN) in the normal population. To this end, we acquired multi-shell diffusion MRI data with 391 gradient directions to estimate the structural connectivity within this functionally-defined network, and evaluated the executive function of the subjects. We used network-based statistic (NBS) to assess the relationships between executive function and the ECN connectivity, and found that the structural connectivity between hemispheres displayed positive correlation with higher executive function performance, while the connectivity within a sub-network in the right hemisphere showed a negative correlation with executive function.

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In vivo Diffusion MRI ODF-Fingerprinting performance relative to an HCP reference
Steven H. Baete1,2, Martijn A. Cloos1,2,3, Ying-Chia Lin1,2, Dimitris G. Placantokanis4, Timothy Shepherd1,2, and Fernando E. Boada1,2

1Center for Advanced Imaging Innovation and Research (CAI2R), NYU School of Medicine, New York, NY, United States, 2Center for Biomedical Imaging, Dept of Radiology, NYU School of Medicine, New York, NY, United States, 3The Sackler Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY, United States, 4Department of Neurosurgery, Perlmutter Cancer Center, Neuroscience Institute, Kimmel Center for Stem Cell Biology, NYU School of Medicine, New York, NY, United States

High quality diffusion acquisitions are routinely used to study white matter architecture and brain connectivity in vivo. A key step for successful tractography of neuronal tracts is correct identification of the tract directions in each voxel. The recently proposed ODF-Fingerprinting method has been demonstrated in computer simulations and qualitative in vivo results to improve detection of fiber pairs with small crossing angles whilst maintaining fiber direction precision. Here we evaluate the performance of ODF-Fingerprinting and several other fiber direction identification algorithms quantitatively in vivo in a downsampled DWI dataset where the high resolution dataset provides a reference standard.

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Towards a deep learning model for diffusion-aware tractogram filtering
Daniel Jörgens1, Philippe Poulin2, Rodrigo Moreno1, Pierre-Marc Jodoin2, and Maxime Descoteaux2

1KTH Royal Institute of Technology, Stockholm, Sweden, 2Université de Sherbrooke, Sherbrooke, QC, Canada

We propose a deep learning model that is able to separate a tractogram into sets of anatomically plausible and implausible streamlines. In contrast to existing methods, our model relies solely on the measured diffusion signal as an input ensuring independence of potential misalignments between subjects. The model is shown to generalize to different tractography methods and has the potential to simultaneously learn from multiple supervisor methods.

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Tractostorm: Evaluation of intra and inter rater reproducibility in tractography dissection
Francois Rheault1, Laurent Petit2, and Maxime Descoteaux1

1Computer Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada, 2IMN UMR 5293, Université de Bordeaux, Bordeaux, France

Investigative studies of white matter structures using tractography often require manual virtual bundle dissection to be performed. Human errors and personal decisions make these manual segmentations hard to reproduce. Reproducibility assessment of raters is common practice in other neuroimaging field where segmentation protocols were refined to maximize reproducibility. However, this has not been done in the field of diffusion tractography. The contribution of this study is to provide the first large-scale, multi-center variability assessment of virtual dissection of tractography dataset.

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Brain tumors: a challenge for tracking algorithms
Guillaume Theaud1, David Fortin2, Felix Morency3, and Maxime Descoteaux1

1Sherbrooke Connectivity Imaging Laboratory (SCIL), Université de Sherbrooke, Sherbrooke, QC, Canada, 2Division of Neurosurgery and Neuro-Oncology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, QC, Canada, 3Imeka Solutions Inc, Sherbrooke, QC, Canada

In tumor cases, several fiber bundles are displaced, destroyed, or infiltrate the tumor zone. For surgical planning, it is important to have the best estimation of the bundles near the tumor and in the edema. In neurosurgical tractography, DTI is the clinical standard and most used tractography method in publications. DTI does not correctly estimate local crossing fibers and is limited by edema contamination. In this work, we compare 4 tracking algorithms (DTI, HARDI deterministic, probabilistic, a new probabilistic edema-informed) applied to tumor cases, show differences and advise on the choice of tractography algorithm to be used in neurosurgical cases.

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Optimized DTI acquisition and tractography pipeline for a reliable reconstruction of the facial nerve in patients with vestibular schwannoma
Manuela Moretto1,2, Valentina Baro3, Sabrina Brigadoi4, Marco Castellaro1,2, Mariagiulia Anglani5, Antonio Mazzoni3, Elisabetta Zanoletti3, Andrea Landi3, Luca Denaro3, Francesco Causin5, Domenico D'Avella3, and Alessandra Bertoldo1,2

1Padova Neuroscience Center, University of Padova, Padova, Italy, 2Department of Information Engineering, University of Padova, Padova, Italy, 3Department of Neurosciences, University of Padova, Padova, Italy, 4Department of Developmental Psychology and Socialisation, University of Padova, Padova, Italy, 5Neuroradiology Unit, University of Padova, Padova, Italy

Vestibular schwannomas (VS) are intracranial tumors that can cause the dislocation of the facial nerve (FN). The location of the FN is therefore a priori unknown to the surgeon and this is the main reason why patients with VS may experience FN damage during the surgery, leading to facial paralysis. In this work we used a multi-shell DTI acquisition to perform probabilistic fiber tracking for the preoperative determination of FN course in patients with VS. High-resolution anatomical scans were used to help the fiber tracking algorithm to obtain a reliable reconstruction also when the FN course had a complex configuration.

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Comparison of diffusion MRI data with different b-values in trigeminal nerve tracking with unscented Kalman filter tractography
Guoqiang Xie1,2, Fan Zhang2, Lorenz Epprecht3, Isaiah Norton2, Yogesh Rathi2, Alexandra J. Golby2, and Lauren J. O'Donnell2

1Nuclear Industry 215 Hospital of Shaanxi Province, Xianyang, China, 2Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 3Cantonal Hospital St. Gallen, St. Gallen, Switzerland

Diffusion MRI enables improved identification of the trigeminal nerve by tracking of its 3-D trajectory. To explore optimal methods for trigeminal nerve tracking using diffusion MRI, we compared tracking results from acquisitions with different b-values using single- and multi-fiber tractography methods. We found that the trigeminal nerve can be best tracked using b=3000 data with a two-tensor fiber model. We suggest that these settings can potentially be suitable for clinical applications, e.g., diagnosis and evaluation of trigeminal neuralgia.

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Toward identifying individual branches of the trigeminal nerve with dMRI-based tractography at 7 Tesla: methodological considerations
Kellen Mulford1, Christophe Lenglet1, Pramod Pisharady1, Sean Moen2, Donald R. Nixdorf3,4, Bharathi D. Jagadeesan2,5, Andrew W. Grande2, and Pierre-Francois Van de Moortele1

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States, 3Department of Diagnostic & Biological Sciences, University of Minnesota, Minneapolis, MN, United States, 4Department of Neurology, University of Minnesota, Minneapolis, MN, United States, 5Department of Radiology, University of Minnesota, Minneapolis, MN, United States

Trigeminal Neuralgia is a debilitating neuropathic condition affecting the trigeminal nerve. Tractography allows for the possibility of identifying the three branches of the nerve to assist in refining the etiopathology of trigeminal neuralgia. In this study we identify methodological factors that contribute to reliability in identifying the branches of the nerve through an analysis of public HCP data and methodological experiments at 7 Tesla. We conclude that the choice of phase encoding direction can dramatically impact the fidelity of cranial nerve tractography results, and that spatial resolution plays an important role in CN-V branch identification.

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Fibre Tracking of the Arcuate Fasciculus at High Spatial and Angular Resolution
Matthew Lyon1, Thomas Welton1, Jerome Maller1,2, MyungHo In3, Ek Tsoon Tan4, Matt Bernstein3, Erin Gray3, Yunhong Shu3, John III Huston3, and Stuart Grieve1,5

1Sydney Translational Imaging Laboratory, Heart Research Institute, The University of Sydney, Sydney, Australia, 2GE Healthcare, Melbourne, Australia, 3Department of Radiology, Mayo Clinic, Rochester, MN, United States, 4GE Global Research, Niksayuna, NY, United States, 5Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia

We compared fibre tracking performance in the arcuate fasciculus across a range of angular resolutions, as well as a low distortion dataset using diffusion MRI data from a Compact 3T scanner with high-performance gradients. Tracking performance increased approximately linearly with greater angular resolution. Performance was also improved using a low-distortion diffusion sequence at a single relatively low angular resolution acquisition (33 directions).

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Altered structural connectivity in the auditory-related pathway in patients with idiopathic sudden sensorineural hearing loss by diffusion spectrum imaging
Zihao Zhang1, Tao Jiang1, Xiuqin Jia1, Xiaojiao Guan1, Qinglei Shi2, Jing Yang3, and Yi Zhang3

1Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China, 2MR Scientific Marketing, Siemens Healthcare, Beijing, China, 3Department of Hyperbaric Oxygen, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China

Sensorineural hearing loss is increasingly recognized as the result of alterations in the auditory-related network. The present study aimed to further explore the whole brain abnormalities of neural network connections in idiopathic sudden sensorineural hearing loss (ISSNHL) through diffusion spectrum imaging. It was found left-sided ISSNHL exhibited decreased connectivity between the contralateral inferior temporal gyrus and rolandic operculum, and the contralateral heschl gyrus and superior marginal gyrus; while increased connectivity was detected between the ipsilateral temporal pole and cuneus, which suggests that DSI could help investigate the structural correlates of these imaging abnormalities in this disease. 

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A surface-based shape analysis of the human corticospinal tract
Gabrielle Grenier1, Étienne St-Onge1, and Maxime Descoteaux1

1Sherbrooke Connectivity Imaging Laboratory (SCIL), Université de Sherbrooke, Sherbrooke, QC, Canada

Traditionally, when examining bundles, comparative methods between measures such as volume, streamline density and mean fractional anisotropy are often used. However, these measures can be biased and do not inform about shape of the white matter bundle. In this work, a new method is proposed to compare bundles based on its surface. Indeed, three measures (area, elongation, irregularity) applied along the cross-sections of the surface enable to highlight shape differences. Here, we illustrate the potential of these surface-based shape measures on the right and the left pyramidal tract in a healthy group of 30 datasets.

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DIPY Horizon: fast, modular, unified and adaptive visualization
Eleftherios Garyfallidis1, Marc-Alexandre Côté2, Bramsh Qamar Chandio1, Shreyas Fadnavis1, Javier Guaje1, Ranveer Aggarwal3, Etienne St-Onge4, Karandeep Singh Juneja5, Serge Koudoro1, and David Reagan6

1Intelligent Systems Engineering, Indiana University, Bloomington, IN, United States, 2Microsoft Research, Montreal, QC, Canada, 3Microsoft, Hyderabad, India, 4Université de Sherbrooke, Sherbrooke, QC, Canada, 5Indian Institute of Technology, Hyderabad, India, 6Pervasive Technology Institute, Indiana University, Bloomington, IN, United States

DIPY Horizon is fast, modular, unified and adaptive visualization system that resembles a high-end game engine, works on the web and across desktop operating systems.  Horizon is suitable both for user, programmers and clinical applications.

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On the regression of intracranial volume in Fixel-Based Analysis
Robert Elton Smith1,2, Thijs Dhollander1,2, and Alan Connelly1,2

1The Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia, 2The Florey Department of Neuroscience and Mental Health, The University of Melbourne, Heidelberg, Australia

Fixel-Based Analysis (FBA) enables robust whole-brain statistical analysis of both microscopic and macroscopic white matter properties that is both sensitive and specific to crossing fibre geometry. Given the influence of macroscopic brain differences in such experiments, interest has been expressed in how best to account for variations in brain volume across participants. Here we demonstrate the effect of brain volume on FBA by synthetically modulating brain sizes within a healthy cohort and statistically testing FBA metrics with various regressions of estimated intracranial volume. We conclude with recommendations for regression of the influence of global brain size differences in FBA when desired.

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Automated Segmentation of the Cortical Boundaries in Native Diffusion Tensor Imaging Space to Measure Anisotropy of the Cerebral Cortex
Graham Little1 and Christian Beaulieu1

1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada

Diffusion tensor imaging (DTI) can quantify anisotropic diffusion in the cerebral cortex reflecting its microstructural architecture. However, the analysis is usually performed by defining the inner and outer cortical boundaries on 3D T1-weighted images which are then applied to co-registered DTI, but this is prone to registration errors. Here we present an automatic cortical boundary segmentation method applied directly to 1.5 mm isotropic DTI acquired in 6 minutes at 3T.  The cortical surfaces derived from DTI alone demonstrate the radial orientation of the primary eigenvector and appropriate FA/MD showing promise for DTI studies of the cortex in neurological disorders.

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Spatial Normalization of Fiber Orientation Distribution (FOD) Maps using Mrtrix and an Image-based Non-uniform Gradient Method
Zifei Liang1 and Jiangyang Zhang1

1Center for Biomedical Imaging (CBI), Department of Radiology, New York University School of Medicine, New York, NY, United States

Diffusion MRI based fiber orientation distribution (FOD) estimates are widely used to examine structural connectivity in the brain. For group comparison using nonlinear spatial normalization, FOD needs to be adjusted based on the estimated degree of rotation and scaling at each voxel. We compared the current method implemented in Mrtrix for spatial normalization of FODs with an image-based method. The results suggest that the method in Mrtrix is accurate for rotation but generates potential bias in FOD peak amplitude and orientation when large anisotropic scaling is present. This knowledge is important for studies to use spatially normalized FOD maps. 

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Characterization of the cerebro-cerebellar loop exploiting advanced tractography and dealing with thalamic synapsis
Fulvia Palesi1, Nicolò Rolandi2, Fernando Calamante3,4, Egidio D'Angelo2,5, and Claudia A.M. Gandini Wheeler-Kingshott2,6,7

1Neuroradiology Unit, Brain MRI 3T Research Center, IRCCS Mondino Foundation, Pavia, Italy, 2Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy, 3School of Aerospace Mechanical and Mechatronic Engineering, University of Sydney, Sydney, Australia, 4Sydney Imaging, University of Sydney, Sydney, Australia, 5Brain Connectivity Center, IRCCS Mondino Foundation, Pavia, Italy, 6Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom, 7Brain MRI 3T Research Center, IRCCS Mondino Foundation, Pavia, Italy

Recently, advanced tractography has been used for assessing the feasibility of characterizing cerebro-cerebellar loop, composed of cerebello-thalamo-cortical and cortico-ponto-cerebellar pathways, acknowledging the issue of how tractography deals with polysynaptic connectivity, i.e. at thalamic level. In this work, polysynaptic cerebello-thalamo-cortical and cortico-ponto-cerebellar pathways were reconstructed using a multiplicative hypothesis for thalamic connectivity. Our findings revealed the importance of using such a multiplication factor for streamlines reaching the thalamic synapses to properly reconstruct cerebro-cerebellar connection. Furthermore, findings using polysynaptic tracts support the cerebellar role in cognition showing that cognitive/associative areas are the mainly involved in both the cerebello-thalamo-cortical and cortico-ponto-cerebellar pathways.


Diffusion MRI: Artefact Correction

Exhibition Hall
Wednesday 8:15 - 9:15
 Diffusion

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Distortion dominates fibre tracking of the optic chiasm – an evaluation of ultra-high angular resolution compared to low-distortion diffusion MRI on a Compact 3T
Thomas Welton1, Matthew Lyon1, Jerome J Maller1,2, Myung-Ho In3, Ek-Tsoon Tan3, Matt A Bernstein4, Erin M Gray4, Yunhong Shu4, John Huston4, and Stuart M Grieve1,5

1Sydney Translational Imaging Laboratory, Heart Research Institute, University of Sydney, Sydney, Australia, 2GE Healthcare, Richmond, Melbourne, Victoria, Australia, 3GE Global Research, Niskayuna, NY, United States, 4Department of Radiology, Mayo Clinic, Rochester, MN, United States, 5Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia

We evaluated the impact of angular resolution and spatial distortion on crossing-fibre tracking accuracy at the optic chiasm using diffusion MRI data from a Compact 3T scanner with high-performance gradients. Contralateral tracking via the chiasm was quantified in acquisitions optimised for q-space resolution or low distortion and compared to the known true rate of decussation. We found that, for chiasmal tracking, minimising the effects of geometric distortion may provide better value than maximising spatial or angular resolution beyond 140 directions. An ideal future diffusion MRI protocol will combine these features for more optimal tracking performance.

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Compensation of signal loss induced by scanner table vibrations in high b-value DW-TSE for measuring lipids ADC
Dominik Weidlich1, Stefan Ruschke1, MingMing Wu1, Andreas Hock2, Rainer Burgkart3, and Dimitrios C. Karampinos1

1Department of Diagnostic and Interventional Radiology, Technical University Munich, Munich, Germany, 2Health Systems Philips Schweiz, Zurich, Switzerland, 3Clinic of Orthopaedic Surgery, Technical University Munich, Munich, Germany

Fat plays a central role in the incidence of metabolic syndrome but current MRI biomarkers cannot answer questions about fat cell microstructure. Diffusion-weighted measurements are capable of revealing information about fat tissue microstructure but the required strong diffusion weighting induces scanner table vibrations that eventually lead to measurement errors and artifacts. The purpose of this work was to mitigate vibration artifacts by placing a vibration compensation gradient before the diffusion preparation. The approach was tested in a water-fat phantom and in-vivo in the lower leg of a healthy volunteer.

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Diffusion Gradient Nonlinearity Correction in a Diffusion Phantom and in Breast Cancer Bone Metastases
Thomas Winther Buus1, Anders Bonde Jensen2, and Erik Morre Pedersen1

1Department of Radiology, Aarhus University Hospital, Aarhus, Denmark, 2Department of Oncology, Aarhus University Hospital, Aarhus, Denmark

The purpose was to investigate if diffusion gradient nonlinearity (DGNL) ADC-errors could be corrected in vitro and in vivo. 

 

Methods

DWIBS was performed in a diffusion phantom and in breast cancer patients. ADC-maps with and without DGNL correction were created and compared at different positions relative to the isocenter. 

 

Results

In the diffusion phantom uncorrected ADC-values 17.5cm from the isocenter dropped by 29-32% while the corrected ADC-values increased by 2-4%.

In 85 bone metastases uncorrected ADC-values 14cm from the isocenter dropped by 18.7% while corrected ADC-values dropped by 2.8%. 

 

Conclusion

DGNL ADC-errors can be corrected in vitro and in vivo.


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Noise2Noise MRI for High-resolution Diffusion-weighted Imaging of the Brain: Deep Learning-based denoising without need for Highly Averaged Ground-truth Images
Motohide Kawamura1, Daiki Tamada1, Satoshi Funayama1, Hiroshi Onishi1, and Utaroh Motosugi1

1Department of Radiology, University of Yamanashi, Chuo-shi, Japan

Deep learning (DL)-based denoising is promising to achieve high resolution diffusion-weighted imaging (HR-DWI) by improving SNR without signal averaging. Training supervised DL-based algorithm, however, requires thousands of teaching data, which need long acquisition time. In this study, we propose to use noise2noise (N2N) theory to develop DL-based denoising algorithm, which does not need teaching data with high SNR. In the results, the proposed method (N2N-MRI-based algorithm) outperformed conventional ground-truth-based algorithm in terms of maximum peak SNRs on validation sets during training.  The image quality of HR-DWI denoised by N2N-MRI-based algorithm was equivalent to that denoised by conventional algorithm.

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Iteration-based motion compensation method for multi-shot diffusion imaging
Zhongbiao Xu1, Rongli Zhang2,3, Yingjie Mei1,4, Zhifeng Chen1, Yaohui Wang5, Ed X. Wu6, Feng Huang7, and Yanqiu Feng1

1School of Biomedical Engineering, Guangdong Provincial Key Laborary of Medical Image Processing, Southern Medical University, Guangzhou, China, 2School of Medicine, South China University of Technology, Guangzhou, China, 3Guangdong General Hospital, School of Medicine, South China University of Technology, Guangzhou, China, 4Philips Healthcare, Guangzhou, China, 5Division of Superconducting Magnet Science and Technology, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China, 6Laboratory of Biomedical Imaging and Signal Processing, University of Hong Kong, Hongkong, China, 7Neusoft Medical System, Shanghai, China

Multi-shot EPI technique is vulnerable to patient motion. Though CIRIS proposed by our group tackles the infrequent macroscopic motion in multi-shot EPI by clustering and registration, it cannot deal with the frequent motion (e.g. shot-wise motion). In this work, an iterative motion compensation frame was introduced to correct for the frequent motion during the multi-shot acquisition. The simulation experiments demonstrated that the proposed method can obtain improved image quality in the presence of infrequent motion, and even correct for the shot-wise motion, compared to CIRIS.

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Impact of processing options on histogram metrics extraction from DWI in cerebral small vessel disease
Ana Fouto1, Rita G. Nunes1, Joana Pinto1, Luísa Alves2,3, Sofia Calado2,3, Carina Gonçalves2,3, Margarida Rebolo4, Miguel Viana Baptista2,3, Pedro Vilela5, and Patrícia Figueiredo1

1Department of Bioengineering, ISR-Lisboa/LARSyS, Instituto Superior Técnico - Universidade de Lisboa, Lisbon, Portugal, 2Neurology Department, Hospital Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal, 3CEDOC - Nova Medical School, New University of Lisbon, Lisbon, Portugal, 4Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal, 5Imaging Department, Hospital da Luz, Lisbon, Portugal

Biomarkers based on diffusion-weighted imaging (DWI) have been proposed as potential disease biomarkers in several brain conditions including cerebral small vessel disease (SVD). Often histogram-based metrics are extracted, but findings across studies are somehow inconsistent. Here, we investigated the impact of several processing options for extracting histogram metrics of fractional anisotropy (FA) and mean diffusivity (MD) from DWI. We considered two white matter regions-of-interest with different interpolation and thresholding options, as well as different numbers of bins. We found that processing options significantly impacted histogram metrics, which in some cases significantly affects the ability to discriminate between patient and controls.

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Corrupted Data Rejection Strategy in k-space Based Multi-shot Diffusion Reconstruction
Zhe Zhang1, Wanlin Zhu1, Jing Jing1,2, Hua Guo3, Jiazheng Wang4, Chun Yuan1,3,5, and Yongjun Wang1,2

1China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China, 2Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China, 3Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, 4Philips Healthcare, Beijing, China, 5Department of Radiology, University of Washington, Seattle, WA, United States

In diffusion imaging, bulk and physiological motion together with strong diffusion encoding gradient introduces extra image phase or data corruption in the diffusion-weighted images. Corrupted data identification/rejection procedure has not been integrated in the recently proposed k-space based multi-shot diffusion reconstruction pipelines. In this work, two corrupted data rejection strategies were proposed, compared and evaluated. Results show that using corrupted data identification and rejection after the CK-GRAPPA reconstruction is potentially a robust choice for multi-shot diffusion imaging reconstruction.

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Correction of systematic errors in DTI imaging caused by gradient nonlinearity using gradient field maps measured by diffusion imaging of an isotropic diffusion phantom.
Alan Seth Barnett1, Mustafa Okan Irfanoglu1, Baxter P Rogers2, Bennett A Landman2, and Carlo Pierpaoli1

1Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD, United States, 2Vanderbilt University Medical Center, Nashville, TN, United States

Gradient nonlinearity causes systematic errors in the measurement of DTI parameters. These errors can be greatly reduced if the actual fields generated by the gradient coils is known. Although the gradient field maps are known to the manufacturers, many users do not have access to them. We describe a method for measuring the gradient field maps using a set of diffusion weighted images of an isotropic diffusion PVP phantom. We use the field maps to analyze a DTI study of the  phantom and compare the results to analysis performed without the field maps. The results show that the method works well.

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Motion Compensation for Free-Breathing Diffusion-Weighted Imaging (MoCo DWI)
Christian Dávid1,2, Thomas Vahle3, Robert Grimm3, Peter Bachert1,2, and Marc Kachelrieß1,4

1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Siemens Healthcare GmbH, Erlangen, Germany, 4Medizinische Fakultät Heidelberg, Heidelberg University, Heidelberg, Germany

Diffusion-weighted imaging (DWI) of the abdomen has acquisition times of several minutes. For this reason respiratory motion can cause misalignment between acquired slices at the same position but different b-values. To overcome this, we estimate the patients’ respiratory motion using a T1-weighted, stack-of-stars GRE pulse sequence and an advanced 4D reconstruction. This motion estimation is used to compensate for respiratory motion in a common, free-breathing DWI acquisition. In three volunteers an improved alignment of structures in the liver are shown. This allows for a better comparison and potential benefits for further processing (e.g. for ADC-maps).

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Effects of Gradient Nonlinearities on Reproducibility and Accuracy of Diffusion MRI Metrics in the Brain.
M. Okan Irfanoglu1, Alan Seth Barnett1, Neda Sadeghi1, and Carlo Pierpaoli1

1Quantitative Medical Imaging/NIBIB, National Institutes of Health, Bethesda, MD, United States

Gradient nonlinearities in MRI cause spatially-varying b-values and diffusion gradient directions. In this work, we  analyze whether these nonlinearities have a significant impact on data reproducibility and accuracy for brain studies.  Our results indicate that not only FA and TR values have an increasing bias away from the isocenter of the magnet,  but also differences in subject positioning and head orientation combined with nonlinearities have a significant effect on reproducibility. The effects were also observed in principal eigenvector directions computed with the tensor model.

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Progress toward on-line implementation of vendor-provided prospective correction for non-uniform diffusion weighting due to gradient nonlinearity
Dariya Malyarenko1, Ajit Devaraj2, Ek T Tan3, Johan Tondeur4, Johannes Peeters5, Yuxi Pang1, Lisa J Wilmes6, Michael A Jacobs7, David C Newitt6, and Thomas L Chenevert1

1Radiology, University of Michigan Health System, Ann Arbor, MI, United States, 2Philips Research Laboratories, Cambridge, MA, United States, 3GE Global Research, Niskayuna, NY, United States, 4Siemens Medical Solutions, Cary, NC, United States, 5Philips MR Clinical Science, Best, Netherlands, 6Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 7Radiology and Radiological Science, John Hopkins University School of Medicine, Baltimore, MD, United States

Feasibility of the prospective correction for non-uniform diffusion weighting due to gradient nonlinearity using scanner-specific gradient design information was previously demonstrated by our academic-industrial partnership (AIP).  Here we report on the progress toward implementation of the prospective correction by leading MRI vendor participants of the AIP on their respective scanner platforms. The vendor-provided on-line correction is benchmarked by comparison to previously validated retrospective off-line processing for uniform gel and flood phantoms, and a human volunteer. Vendor efforts enable comprehensive bias correction for standardization of quantitative DWI applications in multi-center clinical trial environments.

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Gradient nonlinearity-induced bias calibration and correction in diffusion imaging using DIADEM and a simple, uniform gel phantom
Myung-Ho In1, Uten Yarach1, Daehun Kang1, Ek Tsoon Tan2, Erin M Gray1, Nolan K Meyer1, Joshua D Trzasko1, Yunhong Shu1, John Huston1, and Matt A Bernstein1

1Department of Radiology, Mayo Clinic, Rochester, MN, United States, 2GE Global Research, Niksayuna, NY, United States

This study reports a novel gradient nonlinearity (GNL) calibration approach using DIADEM (Distortion-free Imaging Approach with a Double Encoding Method) diffusion imaging. Unlike standard diffusion-weighted echo-planar-imaging (DW-EPI), DIADEM is free from DW-EPI distortions. This allows GNL calibration with a uniform phantom, since confounding effects between DW-EPI and GNL-induced distortions in the calibration are separated.  Direct bias correction could be applied to the corresponding in-vivo data from the DIADEM scans, which results in reliable quantitative diffusion imaging. The feasibility was successfully demonstrated in phantom and in-vivo on a compact 3T system.

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Evaluation of an adapted DWI MRI for improved image quality and tissue differentiation in abdominal MRI – a prospective study in oncologic follow-up examinations
Constantin Dreher1, Tristan Anselm Kuder2, Stefan Windhaber1, Franziska König1, Daniel Paech1, Anoshirwan Tavakoli1, Frederik B. Laun2,3, Florian Flothow2, Regula Gnirs1, Thomas Benkert4, Heinz-Peter Schlemmer1, and Sebastian Bickelhaupt1

1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 3Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany, 4Siemens Healthcare GmbH, Erlangen, Germany

Diffusion-Weighted imaging is a mainstay for oncologic examinations. However, abdominal examinations with standard DWI can be challenged by signal exploration and motion artifacts. This prospective study therefore compares a standard EPI-DWI with an oncologically optimized-DWI, including complex averaging, motion correction between averages, rescaling of motion corrupted averages, and background suppression, in oncological follow-up MRI investigations. A diffusion resolution phantom demonstrated an improved image quality by the optimized-DWI. Image quality analysis of prospectively acquired abdominal DWI MRI examinations in 52 patients showed a significant improvement in image quality and apparent signal-to-background-noise-ratio by optimized-DWI as compared to standard EPI-DWI in oncologic imaging.

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Learned Gibbs Removal in Partial Fourier Acquisitions for Diffusion MRI
Matthew J. Muckley1, Antonios Papaioannou1, Benjamin Ades-Aron1, Daniel K. Sodickson1, Yvonne W. Lui1, Els Fieremans1, Dmitry S. Novikov1, and Florian Knoll1

1Radiology, NYU School of Medicine, New York, NY, United States

Despite significant advances in both denoising and Gibbs artifact removal, in acquisitions such as partial Fourier encoding, noise and Gibbs ringing continue to be an issue. Here we demonstrate that a machine learning approach can extend Gibbs ringing and noise removal to partial Fourier image acquisitions and show results on estimates of diffusion parameters on phantom and brain imaging data.

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An independent phase-based measure for slice outlier rejection in diffusion MRI
Daan Christiaens1,2, Lucilio Cordero-Grande1,2, Joseph V Hajnal1,2, and J-Donald Tournier1,2

1Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom

Detecting and downweighting damaged slices is vital in analysing motion-corrupted dMRI data. Conventional magnitude-based outlier rejection methods rely on intensity model predictions, with the state of the art using slice-to-volume reconstruction. However, in cases with very high outlier prevalence such model prediction is no longer reliable. Here, we introduce a model-independent phase-based measure for detecting motion-induced slice dropouts. We demonstrate its use in neonatal data, and show that it outperforms model-based magnitude techniques in highly damaged data.

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Noise Estimation and Bias Correction of Diffusion Signal Decays: Application to Prostate Diffusion Imaging
Mohammad Alipoor1,2 and Stephan E Maier1,3

1Radiology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden, 2Zenuity, Gothenburg, Sweden, 3Radiology, Brigham and Women's Hospital, Boston, MA, United States

A novel approach to estimate noise and Rician signal bias in diffusion MRI magnitude data is proposed. Rather than relying on repeat measurements for estimation of noise and expected signal, the methods uses multi-b measurements and non-monoexponential signal fits. In addition to noise and bias estimation this approach also provides signal averaging over all b-factors and permits determination of non-monoexponential tissue water diffusion signal decay. Testing was performed with Monte-Carlo simulations and on diffusion-weighted high-b prostate image data obtained with an external coil array.

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Correction of motion artifacts in head and neck diffusion-weighted MRI
Nienke D. Sijtsema1,2, Dirk H.J. Poot2,3, Gerda M. Verduijn1, Mischa S. Hoogeman1, Aad van der Lugt2, Steven F. Petit1, and Juan A. Hernandez-Tamames2

1Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam, Netherlands, 2Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands, 3Department of Medical Informatics, Erasmus MC, Rotterdam, Netherlands

Diffusion-weighted imaging (DWI) is a promising technique for early stratification of responders and non-responders in head and neck chemoradiotherapy. However, data corruption due to swallowing and misalignment reduce the precision of estimated DWI parameters. We investigated different post-processing approaches to improve the reproducibility of the apparent diffusion coefficient (ADC) and demonstrated an improvement in reproducibility from 13.2% to 6.7%. Inter-volume registration showed the largest improvement compared to intra-volume registration and swallowing artifact rejection. The 6.7% reproducibility is sufficient for stratification of responders and non-responders in H&N chemoradiotherapy.

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Deep Learning based displacement transform estimation for EPI distortion correction
Dattesh Dayanand Shanbhag1 and Chitresh Bhushan2

1GE Global Research, Bangalore, India, 2GE Global Research, Niskayuna, NY, United States

In this work, we propose a DL methodology to estimate the displacement field transform (DL_DispMap) from distorted DWI-EPI images. Compared to direct estimation of distortion-free images, we establish that DL_DispMap provides better training accuracy and mitigates the smoothening effect noticed in DL_Direct. The DL_DispMap corrected images are well matched (SSIM = 0.97) to gold-standard INVERSION method based distortion-free images in performance but might be needed to be tuned for an anatomy and system configuration. The method can potentially be also applied for fMRI studies

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Validation of an image-based measurement of gradient non-linearity method and voxel-wise correction of b-values in a HARDI dataset
Yoojin Lee1,2, Adam Kettinger3,4, Bertram Wilm2, Ralf Deichmann5, Nikolaus Weiskopf6, Christian Lambert7, Klaas Pruessmann2, and Zoltan Nagy1

1Laboratory for Social and Neural Systems Research, University of Zürich, Zürich, Switzerland, 2Institute for Biomedical Engineering, ETH Zürich, Zürich, Switzerland, 3Brain Imaging Centre, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary, 4Department of Nuclear Techniques, Budapest University of Technology and Economics, Budapest, Hungary, 5Brain Imaging Centre, Goethe University Frankfurt, Frankfurt, Germany, 6Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 7Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, United Kingdom

Diffusion MRI requires numerous corrective steps in the data processing pipeline. One such step regards the need for voxel-wise correction of erroneous b-values that ensue from the inherent non-linearity of the magnetic field gradients. To estimate the non-linearity we used a simple image-based method that involves a spherical water phantom to measure voxel-wise the apparent diffusion constant. Deviations from the expected value allow estimation of the local b-value. The b-value maps were validated against the spherical harmonic predictions and subsequently used to correct phantom and in-vivo data.

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Minimization of Nyquist ghost artifacts for diffusion-weighted single-refocused spin-echo EPI
Manoj Shrestha1, Ulrike Nöth1, and Ralf Deichmann1

1Brain Imaging Center (BIC), Goethe University Frankfurt, Frankfurt am Main, Germany

In diffusion-weighted (DW) imaging with EPI readout, Nyquist ghost (NG) artifacts might be aggravated due to higher order eddy currents, especially when using monopolar DW gradients in single-refocused spin-echo EPI (srSE-EPI). Both linear and point-by-point phase corrections were tested on DW-srSE-EPI and, for comparison, also on DW twice-refocused spin-echo EPI (trSE-EPI) with intrinsic eddy-current compensation. Both phase correction methods performed equally well for DW-trSE-EPI. However, for DW-srSE-EPI with high b-values, the linear phase correction failed to fully correct NG artifacts. In contrast, point-by-point phase correction yielded considerably better results. This was confirmed in vitro and in vivo.

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HARDI denoising with mean-curvature enhancement PDE on SE(3)
Etienne St-Onge1, Stephan Meesters2, Erick J Bekkers2, Maxime Descoteaux1, and Remco Duits2

1SCIL, Université de Sherbrooke, Sherbrooke, QC, Canada, 2CASA, Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, Netherlands

We present a new High Angular Resolution Diffusion-weighted Imaging (HARDI) mean-curvature enhancement (MCE) on the homogeneous space of positions and orientations, embedded in the rigid body motion group SE(3). Its potential for crossing-preserving enhancement of fiber orientation distribution (FOD) fields is demonstrated. Compared to previous partial differential equation (PDE) enhancements on SE(3), denoising FOD fields with MCE better preserve boundaries, resulting in a lower overall angular error.

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QC-Aautomator: A deep learning based automated artifact detection in dMRI data
Zahra Riahi Samani1, Jacob Alappatt1, Parker Drew1, and Ragini Verma1

1Penn Patho-Connectomics Lab, Radiology, University of Pennsylvania, Philadelphia, PA, United States

We have developed a deep learning based automated Quality Control (QC) tool, QC-Automator, for diffusion weighted MRI data, that will detect different artifacts. This will ensure that appropriate steps can be taken at the pre-processing stage to improve data quality and ensure that these artifacts do not affect the results of subsequent image analysis. Our tool based on convolutional neural nets has 94 – 98% accuracy in detecting the various artifacts including motion, multiband interleaving artifact, ghosting, susceptibility, herringbone and chemical shift. It is robust and fast and paves the way for efficient and effective artifact detection in large datasets.

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D-stripe: correction for stripe artefacts in diffusion MRI using a combined deep neural network and SVR approach
Maximilian Pietsch1,2, Daan Christiaens2,3, J-Donald​ Tournier1,2, and Joseph​ V. Hajnal2,3

1​Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 3Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences,​ ​ King’s ​ College​ ​ London, King's College London, London, United Kingdom

We present a data-driven method for the correction of stripe artefacts in multi-shell diffusion data that might arise for example from spin-history or stimulated echo effects. It relies on a filter, based on a deep neural network trained with simulated data to detect and remove stripe artefacts from single volumes. This is used to destripe signal predictions obtained from a slice to volume reconstruction, which are then projected onto the input data to determine the appropriate modulation field. The corrected input data are then reconstructed again with reduced stripe artefacts. This approach is applied to super-resolution reconstructions of neonatal multi-shell high angular resolution data.

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Distortion Correction of Multi-Shot Diffusion-Weighted Echo-Planar Imaging using Reversed Gradient Acquisition and Joint Reconstruction
Xiaoxi Liu1, Di Cui1, Edward S. Hui1,2, Queenie Chan3, and Hing-Chiu Chang1

1Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China, 2The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China, 3Philips Healthcare, Hong Kong, China

Multi-shot diffusion-weighted echo-planar imaging (DW-EPI) with multiplexed sensitivity encoding (MUSE) is a self-navigated technique that can achieve high resolution diffusion-tensor imaging (DTI) without the need of navigator echo. However, even with multi-shot acquisition, the effective echo spacing is still relatively long for acquisition of high resolution DTI, leading to significant geometric distortion. In this study, we aim to reduce the geometric distortion of multi-shot DW-EPI by 1) integrating the reversed gradient acquisition in multi-shot DW-EPI, and 2) developing a joint reconstruction method that can reconstruct non-uniform k-space data by taking the off-resonance effect into account.

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Dual-echo blip reversed EPI acquisition enables distortion correction in the presence of motion in diffusion-weighted MRI
Onur Afacan1, W. Scott Hoge2, Tess E. Wallace1, Ali Gholipour1, Sila Kurugol1, and Simon K. Warfield1

1Boston Children's Hospital and Harvard Medical School, Boston, MA, United States, 2Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States

Slice-to-volume registration methods have been shown to provide motion robust reconstruction for large and frequent motions. One challenge with motion correction is the changing magnetic field inhomogeneities with different head positions. In this work we implemented a dual-echo blip reversed EPI acquisition and show that this sequence can be used to reduce distortions in large and frequent motions and can improve slice-to-volume registration results.


Diffusion: Neuro Applications

Exhibition Hall
Wednesday 8:15 - 9:15
 Diffusion

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Mapping anatomical connectivity: a Structural Network Analysis in Early and Profoundly Deaf people.
Francesca Saviola1, Lisa Novello1, Chiara Maffei2, Stefania Benetti1, Ceren Battal3, Stefania Mattioni3, Olivier Marie Claire Collignon1,3, and Jorge Jovicich1

1CIMeC, Center for Mind/Brain Sciences, University of Trento, Rovereto (TN), Italy, 2Athinoula A. Martinos Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 3Institute of Research in Psychology (IPSY) and in Neuroscience (IoNS), University of Louvain, Louvain-la-Neuve, Belgium

In case of early acquired deafness, auditory deprived temporal regions massively enhance their response to stimuli from remaining senses. This so called cross-modal plasticity also alters functional connectivity between reorganized temporal regions and those from preserved senses.  The extent and distribution of white matter structural alterations supporting these functional effects are still poorly understood. In this diffusion MRI study, we investigate white matter reorganization of early deaf relative to hearing controls. Further, since early deaf typically become fluent at sign language, which may itself also induce brain structural reorganization unrelated to deafness, we also include a group of hearing signers.

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Structural connectivity between cerebellum and cerebral cortex in idiopathic generalized epilepsy: a diffusion tensor imaging study
Sisi Jiang1, Xiangkui Li1, Yan Chen1, Dezhong Yao1, and Cheng Luo1

1University of Electronic Science and Technology of China, Chengdu, China

Probabilistic tracking method was applied to study the cerebellar efferent and afferent fibers in the patients with idiopathic generalized epilepsy (IGE), trying to address the structural connectivity (SC) alteration in the cerebello-cerebral circuit compared with healthy controls. Present findings suggested cerebellar effects on ganglia-thalamo-cortical circuit, which might be responsible for motion and cognition impairments in IGE. Furthermore, unbalanced SC alterations in the efferent and afferent fibers between frontal cortex and cerebellum might help to understand specific physiopathologic mechanism in IGE.

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Difference in Tensor Metrics between the Survived and Infarcted Penumbra by Reperfusion in a Rat Model of Cerebral Ischemia
Yu-Chieh Jill Kao1,2,3, Jun Tazoe3,4, Chia-Feng Lu5, Bao-Yu Hsieh6, and Cheng-Yu Chen1,2,3,7

1Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan, 2Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 3Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan, 4Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan, 5Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, 6Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan, 7Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan

We demonstrated significant difference in FA and q-value between destined-survived and destined-infarcted penumbral tissue by reperfusion in transient MCA occlusion animals, which may imply the possible application of DTI-MRI in the evaluation of salvageable tissue before mechanical thrombectomy for acute stroke.

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Graph-based Structural Connectivity is correlated with Children Intelligence Quotient Scores
Ilaria Suprano1, Gabriel Kocevar1, Claudio Stamile1, Salem Hannoun2, Pierre Fourneret3, Olivier Revol3, Fanny Nusbaum1, and Dominique Sappey-Marinier1,4

1Université Claude Bernard-Lyon 1, lyon, France, 2American University of Beirut, Beirut, Lebanon, 3Hôpital Neurologique, Hospices Civils de Lyon, Bron, France, 4CERMEP - Imagerie du Vivant, Bron, France

The neural substrate of high intelligence performances remains not well understood. We propose to investigate the structural brain connectivity measurements and their relationship with the intelligence performances, as measured by the WISC-IV scores of 57 children. We found strong correlations between children brain network density and intelligence scores. Moreover, several correlations were found between integration and redundancy graph metrics suggesting that intelligence performances are probably related to homogeneous network organization.

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High-Resolution FLAIR DTI Tractography of the Fornix in Multiple Sclerosis
Diana Valdés Cabrera1 and Christian Beaulieu1

1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada

Diffusion tensor imaging (DTI) tractography of the human fornix is biased by partial volume effects from cerebrospinal fluid (CSF) due to its small bundle size and intra-ventricular location, even when using high spatial resolution. These errors in diffusion parameter estimation and tracking of the fornix will worsen with axonal loss in multiple sclerosis (MS). Here we demonstrate the superiority of FLAIR-DTI, even when compared to high-resolution 1.5 mm isotropic DTI, to mitigate CSF contamination of fornix tractography in MS and healthy volunteers. FLAIR-DTI yields more accurate diffusion metrics in both cohorts, and still shows abnormal fornix in MS.

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Brain White Matter Abnormality Induced by Chronic Spinal Cord Injury in the Pediatric Population: A Tract Based Spatial Statistic Study
Joshua Fisher1, Mahdi Alizadeh1, Devon Middleton1, Caio Matias1, MJ Mulcahey1, Feroze Mohamed1, and Laura Krisa1

1Thomas Jefferson University, Philadelphia, PA, United States

Few studies have quantified the change in cortical white matter tracts following chronic spinal cord injury in a pediatric population. Additionally, no work has been done to compare chronic SCI subjects with different American Spinal Injury Association Impairment (AIS) scale classifications. We hypothesized that these cortical changes can be detected using tract-based spatial statistics (TBSS). Our efforts revealed that significant changes in fractional anisotropy occur in several motor and sensory related regions. We conclude that TBSS can be effectively used to identify alterations in brain microstructure in a chronic pediatric spinal cord injury population.

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Measuring white matter damage in different types of MS
Chunyu Song1, Peng Sun2, Anne H. Cross3, Zezhong Ye4, and Sheng-Kwei (Victor) Song5

1Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States, University City, MO, United States, 2Radiology, Washington University School of Medicine, St. Louis, MO, United States, University City, MO, United States, 3Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States, Saint Louis, MO, United States, 4Chemistry, Washington University in St. Louis, st louis, MO, United States, 5Radiology, Washington University School of Medicine, St. Louis, MO, United States, Saint Louis, MO, United States

A new diffusion histology imaging (DHI) is proposed to model intra and extra axonal diffusion along with isotropic diffusion within an image voxel of diffusion-weighted MR images. It resolves crossing fibers while more accurately detecting and quantifying axonal injury, axon loss, demyelination, edema and inflammation. Through the multiple-tensor modelling of diffusion-weighted MRI signals, DHI has shown the potential to detect underlying pathologies of normal appearing corpus callosum in all clinical subtypes of multiple sclerosis.

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Evaluating Neurite Density and Orientation in the White Matter of Youth Born with Congenital Heart Disease
Kaitlyn Easson1, Jean-Christophe Houde2, Guillaume Gilbert3, Kimberly Fontes1, Charles Rohlicek4, Christine Saint-Martin5, Annette Majnemer6, Maxime Descoteaux2, and Marie Brossard-Racine1

1Advances in Brain & Child Development Research Laboratory, Research Institute of the McGill University Health Centre, Montreal, QC, Canada, 2Sherbrooke Connectivity Imaging Lab, Université de Sherbrooke, Sherbrooke, QC, Canada, 3MR Clinical Science, Philips Healthcare, Markham, ON, Canada, 4Division of Cardiology, Montreal Children's Hospital, Montreal, QC, Canada, 5Division of Radiology, Montreal Children's Hospital, Montreal, QC, Canada, 6School of Physical & Occupational Therapy, McGill University, Montreal, QC, Canada

In this study, neurite orientation dispersion and density imaging (NODDI) was used to quantify neurite density and orientation in white matter tracts in youth born with congenital heart disease (CHD). Neurite density index was significantly lower in youth born with CHD as compared to control youth in numerous, widespread association tracts. There were no regional differences in orientation dispersion index that survived correction for multiple comparisons. Our findings suggest a predominant role for lower neurite density, rather than lower neurite coherence and organization, in the white matter abnormalities observed in youth born with CHD.

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Structural brain connectivity network alterations following mild traumatic brain injury
Timo Roine1, Mehrbod Mohammadian2,3, Timo Kurki2,3, Jussi Hirvonen2,3,4,5, and Olli Tenovuo2,3

1Turku Brain and Mind Center, University of Turku, Turku, Finland, 2Department of Neurology, University of Turku, Turku, Finland, 3Division of Clinical Neurosciences, Traumatic Brain Injury Centre, Turku University Hospital, Turku, Finland, 4Turku PET Centre, Turku University Hospital, Turku, Finland, 5Department of Radiology, University of Turku, Turku, Finland

We used graph theoretical analysis to investigate structural brain connectivity networks in mild traumatic brain injury (mTBI). Global and local measures of structural connectivity were investigated in acute/sub-acute and chronic phases after TBI. There were no statistically significant differences in the global network measures between patients and controls at either of the stages after TBI. Node-level differences were found between patients and controls in local efficiency, strength, and betweenness centrality in several brain regions. However, only betweenness centrality in the right pars opercularis endured the Bonferroni correction for multiple comparisons.

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White matter Fractional Anisotropy measures in Autism Spectrum Disorder. Implications of differences in structural correlation with performance IQ measures and age. Results from EU- Autism Interventions data.
Robert Anthony Dallyn1,2, Pedro Angel Luque Laguna1,2,3, Cate Davidson1,2,3, EU-AIMS2 TRIALS Consortium1,2, Declan Murphy1, and Flavio Dell'Acqua1,2

1Forensic and Developmental Neuroscience, King's College London, London, United Kingdom, 2Natbrainlab, King's College London, London, United Kingdom, 3Neuroimaging, King's College London, London, United Kingdom

We present voxel-wise statistics on Fractional Anisotropy from EU-AIMS diffusion imaging data on Autism Spectrum Disorder. We validate previous findings of structural white matter abnormalities in a younger cohort. Correlation analysis of white matter development with behavioural tasks points to altered functioning in ASD individuals in visuospatial reasoning tasks, consistent with the central coherence theory of autism. Cohort differences between ASD and control of white matter integrity correlation with age hint toward altered developmental trajectory in Autism Spectrum individuals.

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White Matter Microstructural Alternations in Neuropsychiatric Systemic Lupus Erythematosus With Normal Appearing Brain Using Diffusion Tensor Imaging
Jyh-Wen Chai1,2, Ni-Jung Chang1, Tsung-Yung Li1, Yi-Ying Wu1,3, Li-Ying Fan 4,5, and Clayton Chi-Chang Clayton Chen1,6

1Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan, 2College of Medicine, China Medical University, Taichung, Taiwan, 3Department of Medical Imaging and Radiological Sciences, Central Taiwan University of Sciences and Technology, Taichung City, Taiwan, 4College of Human Development and Health, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan, 5Department of Thanatology and Health Counseling, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan, 6Department of Biomedical Engineering, Hung Kuang University, Taichung City, Taiwan

Systemic lupus erythematosus (SLE) patient has neuropsychiatric signs and symptoms, called neuropsychiatric SLE (NPSLE), usually with increased mortality and morbidity rates. There was little known about pathogenic mechanisms leading to neuropsychiatric symptoms in SLE. The aims of this study attempt to investigate diffusion tensor imaging (DTI) in detection of white matter micro-structural alternations for NPSLE patients, who had normal appearing brain in conventional MRI. By using the TRACULA analysis, we found significant differences of mean diffusivity (MD) and fraction anisotropy (FA) in several important nerve tracts between NPSLE patients and normal subjects, which would be helpful in understanding the mechanisms of NPSLE.

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Reproducibility of the diffusion of the perivascular space in older adults with dementia.
Christopher Steward1, Vijay Venkatraman1, Elaine Lui2, Charles Malpas1, Kathyrn Ellis1, Terence O'Brien1, Nicola Lautenschlager1, and Patricia Desmond1

1University of Melbourne, Melbourne, Australia, 2Royal Melbourne Hospital, Melbourne, Australia

Recently, there has been interest in the glymphatic system and its role in flushing amyloid ß along with other waste products in the brain. New imaging techniques are being developed to try and measure such activity. Recently, diffusion tensor MRI was used to construct an index "DTI-ALPS" to help link dementia burden with diffusion in the perivascular space. We aimed to replicate this study in 36 patients (16 AD, 16 MCI, and 4 SMC). Significant correlations were found between DTI-ALPS and stratified Mini-Mental State Examination score.  Further work is needed to evaluate the feasibility of MRI to measure glymphatic activity.

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Multivariate characterization of brain white matter maturation related to intellectual ability in children
Yannan Cheng1, Chao Jin2, Xianjun Li2, Congcong Liu2, Miaomiao Wang2, Xiaocheng Wei3, Yuli Zhang2, Fan Wu2, Mengxuan Li2, and Jian Yang2

1Department of Radiology, the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi’an, China, 2the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi'an, China, 3MR Research China, GE Healthcare, Bei Jing, People's Republic of China, Bei Jing, China

Brain maturations are thought to relate to behavioral acquisitions and cognitive development. Nevertheless, in vivo investigations of such relationships remain scarce in childhood. To bridge this gap, a multivariate index (DM), which delineates the “maturational distance” between children and adults and leverages DTI-metrics complementarity, was utilized to characterize WM variation. We found that DM showed significantly negative correlations with FSIQ in children aged 4-12 yr, especially in cingulum and superior longitudinal fasciculus. Besides, left hemispheric lateralization (higher correlations with FSIQ) was also observed. Our findings suggest DM as a useful biomarker in detailing the brain WM maturation related to intelligence.

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Alterations of brain white matter tracts in children with abnormal intelligence quotient
Yannan Cheng1, Chao Jin2, Xianjun Li2, Congcong Liu2, Miaomiao Wang2, Xiaocheng Wei3, Yuli Zhang2, Fan Wu2, and Jian Yang2

1Department of Radiology, the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi’an, China, 2the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, Xi'an, China, 3MR Research China, GE Healthcare, Bei Jing, People's Republic of China, Bei Jing, China

Studies have shown that brain white matter microstructure is of crucial importance for intelligence. Here, we detailed the alterations of brain white matter tracts in children with abnormal intelligence quotient by comparing the difference of brain white matter tract between the two groups and exploring correlations with intelligence scores based on DTI parameters. Significant differences of ILF, IFO and SLF were found in children with abnormal intelligence quotient. And all these tracts were strongly correlated with intelligence quotient, suggesting the underlying structural origins of lower cognitive function. 



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High Spatial Resolution Multi-shell DTI in Children and Young Adults Prenatally Exposed to Alcohol
Pascal Tétreault1, Sarah Treit1, Graham Little1, Emily Stolz1, and Christian Beaulieu1

1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada

Diffusion tensor imaging (DTI) has identified white matter differences in individuals with prenatal alcohol exposure (PAE). The current study uses higher spatial resolution of 1.5 mm isotropic (3.4 mmvoxels) and larger b-values of 2000 s/mm(in addition to typical 1000 s/mm2) to assess the brain in children to young adults with PAE. Using the ICBM DTI template regions-of-interest for white matter, the b2000 tensor metrics (but not b1000) showed group differences in the left medial lemniscus and left stria terminalis, the latter also showing correlations with age in the control group but not the PAE group.

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A fixel-based analysis of diffusion properties of white matter fiber in Williams Syndrome
Michael A Green1,2, Kelsie Boulton3, Richard Webster4, Melanie Porter3, and Caroline D Rae1,2

1Neuroscience Research Australia, Sydney, Australia, 2School of Medical Sciences, University of New South Wales, Sydney, Australia, 3Centre for Research in Atypical Neurodevelopment, Macquarie University, Sydney, Australia, 4T.Y. Nelson Department of Neurology, Children's Hospital at Westmead, Sydney, Australia

Williams Syndrome (WS) is a genetic neurodevelopmental disorder produced by a hemideletion of around 26 genes on chromosome 7 (7q11.23) that leads to unique changes in physical and cognitive profiles. Behavioural characteristics including hyper-sociability, excessive friendliness and empathy, sensitivity to loud noises and visual-spatial construction deficits infer unique brain structure and connections. WS is also characterised by reduced muscle tone and a decrease in motor coordination and balance1. We show significant differences in the corticospinal tract in WS participants and that white matter changes previously reported are more likely to be due to morphological changes to the fiber bundles rather than microstructural ones.

3430
Computer 92
Abnormal brain white matter volume underlying methamphetamine abusers: A machine learning approach
Wentao Lai1, Mei Yang2, Zhifeng Zhou1, Wentao Jiang1, Xia Liu1, Gangqiang Hou1, Long Qian3, Zhi Kong2, and Haiyan Run2

1Department of Radiology, Shenzhen Mental Health Center, Shenzhen Kangning Hospital, Shenzhen, China, 2Department of Drug Dependence, Shenzhen Kangning Hospital, Medicine Division of Shenzhen University, Shenzhen, China, 3GE Healthcare, MR Research China, Beijing, China

The disruption of specific microstructural features of white-matter (WM) has been observed in methamphetamine (MA) abusers. However, it remains unknown whether WM volume is abnormal in MA abusers. To address this issue, a machine learning approach was applied in this study to differentiate between 21 MA abusers and 13 age- and gender- healthy controls. Our results showed that a linear support vector machine classifier achieved an accuracy of 73.53% using the white matter volume as input features. Particularly, the most discriminative WM regions included pontine crossing tract, motor system and the reading related network. 

3431
Computer 93
Diffusion MRI detects changes in the Hippocampus and Fimbria-Fornix Circuit in 2 months old 3xTg-AD mice
Maria Fatima Falangola1,2, Xingju Nie1,2, Emilie T. McKinnon1,2,3, Joseph A. Helpern1,2,3,4, and Jens H. Jensen1,2,4

1Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States, 2Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, United States, 3Department of Neurology, Medical University of South Carolina, Charleston, SC, United States, 4Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States

The triple transgenic mouse model (3xTg) of Alzheimer’s disease (AD) exhibits both Aβ and tau pathology. Interestingly, the first detectable pathological features in this model are alterations in overall myelination patterns leading to white matte disruption as early as 2 months of age. Here we investigated the sensitivity of diffusion MRI (dMRI) to detect brain changes in young 3xTg mice. Our results indicate that dMRI is able to capture brain microstructural alterations associated with the hippocampus-fimbria-fornix circuit in 2 months-old 3xTg-AD mice, thus demonstrating dMRI as a viable tool for studying abnormal pathology in this AD mouse model.

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3D Diffusion MRI of Perivascular Fluid Movement: Towards Non-Invasive Mapping of Glymphatic Function.
Phoebe Evans1, Bernard Siow1,2, Ian Harrison1, Ozama Ismail1, Yolanda Ohene1, Payam Nahavandi 1, David Thomas3,4, Mark Lythgoe1, and Jack Wells1

1Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, United Kingdom, 2The Francis Crick Institute, London, United Kingdom, 3Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, London, United Kingdom, 4Leonard Wolfson Experimental Neurology Centre, UCL Queen Square Institute of Neurology, London, United Kingdom

Within the glymphatic system, CSF is transported in a network of perivascular channels where it exchanges with ISF to drive drainage of unwanted solutes, like amyloid- β, out of the brain. Perivascular channel impairment may be an early biomarker of neurodegenerative processes. Here, we present a pilot study for 3D non-invasive assessment of glymphatic function in the rat brain using ultra-long echo time diffusion MRI. We show that this technique is sensitive to the fluid movement in downstream perivascular channels that drives glymphatic inflow.

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DW-MRI and FDG-PET as an Imaging Biomarker for Biological Response to Fast Neutron Exposure
Kyung Jun Kang1, Ki Hye Jung1, In Ok Ko1, Yong Jin Lee1, Kyo Chul Lee1, and Ji Ae Park1

1Division of Applied Radioisotope, Korea Institute Radiological and Medical Sciences, Seoul, Korea, Republic of

In this study, we monitored biological response in neutronexposed normal mouse brains using DW-MRI and 18F-FDG-PET. DW-MRI and 18F-FDG-PET were sensitive enough to detect physiological changes that were not identified in the H&E results. These results suggest that DW-MRI and 18F-FDG-PET can be used as imaging biomarkers to provide a quantitative indicator of complex in vivo pathological changes. Assessment of radiation exposure using imaging biomarkers is non-invasive and can be used repeatedly in clinical practice. In addition, it should be applied not only for evaluating the therapeutic effects of tumors, but also for evaluating the degree of tissue damage by radiation exposure.

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Functional and microstructural alterations in the rat hippocampus after repetitive mild traumatic brain injury
Ahmad Raza Khan1, Brian Hansen1, Nina K Iversen1, Jonas Lynge Olesen1,2, Mariana Angoa Perez3, Donald M .Kuhn3, and Sune N Jespersen1,2

1Clinical Medicine, Aarhus University, Århus C, Denmark, 2Department of Physics and Astronomy, Aarhus University, Aarhus C, Denmark, 3John D. Dingell VA Medical Center, Wayne State University, Detroit, MI, United States

Repetitive mild traumatic brain injury (mTBI) causes subtle tissue injury, which often reports normal under CT and MRI, leading to suboptimal diagnosis and increase the risk of developing neurological disorders. We probe microstructural alterations using advanced diffusion MRI, and perfusion MRI based cerebral blood flow (CBF) in rats before and after repetitive mTBI. Mean diffusivity and radial kurtosis tensor (WT) indicate the microstructural alteration in the ipsilateral hippocampus (IHP) and ipsilateral corpus callosum (ICC) respectively, and CBF maps show a significant reduction in the IHP. Our study suggests that multimodal imaging can provide useful information for early diagnosis of repetitive mTBI.

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Structural and Functional Characteristics of the Common Marmoset Brain Assessed Using Connectome Analysis
Yawara Haga1,2,3,4, Junichi Hata2,3,4, Fumiko Seki2,3,4, Akiko Uematsu3, Mai Mizumura1,3, Takaaki Kaneko2,3, Hideyuki Okano2,3, and Akira Furukawa1

1Radiological Sciences, Tokyo Metropolitan University Graduate School, Tokyo, Japan, 2Department of Physiology, Keio University School of Medicine, Tokyo, Japan, 3Laboratory for Marmoset Neural Architecture, Center for Brain Science, RIKEN, Wako, Japan, 4Live Imaging Center, Central Institute for Experimental Animals, Kawasaki, Japan

Connectome analysis with magnetic resonance imaging (MRI) is a non-invasive method and is an important approach for assessing brain networks and neurological diseases from a multilateral perspective. We examined the structural and functional characteristics of the common marmoset brain using structural and functional connectome analyses. For these connectome analyses, diffusion-weighted imaging and true-awake resting-state functional MRI (rsfMRI) were performed using a 9.4-T MRI scanner. The structural connectome analysis showed that the visual region had the most prominent structural characteristics in the marmoset brain. In addition, functional connectome analysis indicated that the functional connectome results were affected by the rsfMRI environment.

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Ex vivo Structural Connectomics of the Mouse Brain Subcortical Regions
Eunbee Kim1 and Hyeon-Man Baek1,2

1GAIST, Incheon, Korea, Republic of, 2Lee Gil Ya Cancer & Diabetes Institute, Incheon, Korea, Republic of

Parkinson's disease (PD) is one of the degenerative brain disease and the hallmark of PD is the death of dopaminergic cells. The subcortical area involved in neuronal circuits which play a central role in the motor control. Structural connectivity can identify abnormal connectivity of neural circuits. Diffusion tensor imaging (DTI) is a non-invasive technique that has been used to delineate the internal anatomy by tracing white matter tracts. In this study, we investigated ex vivo diffusion MR images using perfusion methods and identify the structural connectivity in subcortical regions. In conclusion, we provide structural connectional fingerprints in the mouse model. 

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Readout segmented EPI based Relative  apparent diffusion coefficient in early monitoring the treatment effect of low-intensity transcranial ultrasound: evaluation  in a rat permanent occlusion model
Lanxiang Liu1, Juan Du2, Tao Zheng1, Xuemei Wang1, Huiling Yi1, Shuang Wu1, Qinglei Shi3, and Shuo Wu2

1Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 Hospital, Qinhuangdao, China, 2Graduate School of Hebei Medical University, Shijiazhuang, China, 3MR Scientific Marketing, Siemens Healthcare, Beijing, China

Acute ischemic stroke is a common and frequently occurring disease that severely harms human health and has high morbidity and mortality. Low-intensity transcranial ultrasound (LIPUS), due to its advantages of higher spatial resolution and greater penetration depth, has emerged as a new modality for noninvasive neuromodulation. This study indicated that the rADC based on readout segmented EPI sequence is a good indicator to evaluate the curative effect of LIPUS on acute cerebral infarction treatment. 


Diffusion: Body Applications

Exhibition Hall
Wednesday 8:15 - 9:15
 Diffusion

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Comparison of IVIM Model, Kurtosis Model and IVIM-Kurtosis Model for the Grading of Hepatocellular Carcinoma
Yue Lin1, Chunmei Li1, and Min Chen1

1Beijing Hospital, Beijing, China

IVIM model and DKI model cover different aspects of diffusion, thus a combined IVIM-DKI model might describe diffusion in perfused biological tissues more accurately. The aim of the study was to quantitatively compare the potential of various parameters obtained from IVIM model, Kurtosis model and IVIM-Kurtosis model in the grading of hepatocellular carcinoma (HCC). We enrolled 24 HCC patients who underwent multiple b values Diffusion-Weighted Imaging (DWI) with subsequent pathological confirmation. Our results showed that all three models could differentiate high-grade HCC from low-grade HCC and IVIM-Kurtosis model may be superior to IVIM model.

3439
Computer 102
Correlation between IVIM parameters and cT1 in HCV patients
Michele Nicastro1, Nicola Martini2, Matteo Milanesi3, Chloe Hutton3, Antonio Salvati4, Daniele Della Latta2, Maurizia R. Brunetto4,5, Matthew Robson3, Luigi Landini2,6, and Dante Chiappino2

1Dept of Physics, Vision Lab, University of Antwerp, Antwerp, Belgium, 2Fondazione Toscana "G.Monasterio", Massa, Italy, 3Perspectum Diagnostics, Oxford, United Kingdom, 4Hepatology Unit, University Hospital of Pisa, Pisa, Italy, 5Dept Clinical and Experimental Medicine, University Of Pisa, Pisa, Italy, 6Dept of Information Engineering, University Of Pisa, Pisa, Italy

IVIM imaging has been investigated by several researchers to understand its clinical potential. However, the dependency from b-value distribution and the effect of confounding factors such as iron and steatosis make hard to draw conclusion. In this work, a multiparametric protocol was proposed to address those confounds and the correlation with iron-corrected T1 (cT1) was studied in a group of patients affected by hepatitis C. The vascular volume fraction F shows a statistically relevant correlation with cT1 (p<0.001).

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DTI of Spinal Cord Lesions of Varying Severity Based on MRI in the Entire Pediatric Spinal Cord
SONA SAKSENA1, Feroze B Mohamed1, Devon M Middleton1, Laura Krisa1, Mahdi M Alizadeh1, Shiva Shahrampour1, Chris C Conklin1, Adam Flanders1, Jürgen Finsterbusch2, MJ Mulcahey1, and Scott H Faro3

1Thomas Jefferson University, Philadelphia, PA, United States, 2University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 3Johns Hopkins School of Medicine, Baltimore, MD, United States

To determine whether DTI at sites cephalad and caudal to the MRI lesion provides measures of cord abnormalities in different SCI groups (n=23) compared to TD (n=36) and any correlation between the varying severity of MRI abnormality and DTI abnormalities cephalad and caudal to the MRI lesion. to the MRI lesion. The five SCI groups included; 1= SCIWORA (n=6); 2=Syringohydromyelia (n=4); 3=Atrophy+Syringomyelia (n=7); 4=Atrophy+Myelomalacia (n=3); 5=Atrophy+Hemorrhage (n=3). Groups 1 to 5 represent a progressive measure in cord abnormality. Among these SCI groups, we looked at concordant DTI correlation which is defined as the expected change in DTI metrics with increasing cord severity. SCIWORA showed DTI abnormality at segments of the cephalad and caudal cord with the caudal cord more affected consistent with the anterograde degeneration. FA showed the greatest total number of segments in the cephalad and caudal cord that showed abnormal DTI values in comparison to the other DTI metrics.

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Assessment of Traumatic Peripheral Nerve Injury and Carpal Tunnel Syndrome with Diffusion Tensor Imaging
Michael Pridmore1, Wesley P. Thayer2, Mark D. Does3, and Richard D. Dortch4

1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Plastic Surgery, Vanderbilt University Medical Center, Nashville, TN, United States, 3Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 4Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States

Clinical management following traumatic peripheral nerve injury and carpal tunnel release surgeries requires physicians to rely on qualitative measures from patient history and physical exams. The resulting delays in clinical decision-making can lead to a negative impact on patient outcomes because the regeneration of nerves must occur in a timely fashion to avoid permanent muscle atrophy and loss of sensorimotor function. The current study aims to test the feasibility of performing diffusion tensor imaging in the nerves of the wrist to provide a noninvasive and reliable tool that can monitor patient outcomes and improve clinical decision-making after surgical interventions.

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Computer 105
Inter- and intraobserver reproducibility of two different delineation of intravoxel incoherent motion in differentiating benign and malignant thyroid nodule
Yunlong Yue1, Minghui Song1, Yanfang Jin1, Jinsong Guo1, Lili Zuo1, Queenie Chan2, and Zhenchang Wang3

1MR Department, Beijing Shijitan Hospital of Capital Medical University, Beijing, China, 2Philips Healthcare, Hong Kong, China, 3Beijing Friendship Hospital, Capital Medical University, Beijing, China

To compare the reproducibility and diagnostic performance of IVIM parameters derived from 3D whole-lesion (W-L ROI) and single-section (S-S ROI) delineation respectively . Forty-three patients with 46 pathologically confirmed thyroid nodules were involved. Reduced FOV DWI with 2D RF was employed to decrease the distortion. The ICC values of all IVIM parameters were higher with W-L ROI delineation than with S-S ROI delineation. The 95% limits of agreement (Bland-Altman plots) determined by W-L ROI revealed smaller absolute intra- and interobserver variability and the AUC of W-L ROI delineation was higher than S-S ROI according to ROC analysis.

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Application of Whole-Body Diffusion-Weighted MRI Imaging with Apparent Diffusion Coefficient Mapping for the Evaluation of Depth of Response to Therapy in Multiple Myeloma
Menglong Zheng1, Xinxing Ma1, and Daohai Xie1

1The First Affiliated Hospital of Soochow University, Soochow, China

Whole-body diffusion-weighted magnetic resonance imaging (WB-DWI MRI) is an important imaging technique of great supplementary diagnostic value to the evaluation of treatment response in patients with multiple myeloma (MM). Conventional radiography which has been widely avaiable for the identification of myeloma-related bone lesions both at diagnosis and during disease course is of limited value to the assessment of response to therapy or disease relapse in MM, as lytic bone lesions rarely show signs of healing despite response to therapy. WB-DWI MRI with the measurement of apparent diffusion coefficient (ADC) value is an effective way for quantitatively comparing the differences in water diffusion among normal marrow, active pathologic marrow and that in remission. In this work, we report the preliminary results of the application of WB-DWI MRI in discriminating deep response to induction therapy for newly diagnosed MM patients.

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Non-Gaussian IVIM-DWI for prediction of locoregional failure in nasopharyngeal carcinoma
Ramesh Paudyal1, Jung Hun Oh1, Jonathan E Leeman2, Xinmao Song3,4, Amresha K Shridhar1, Eve LoCastro1, Vaios Hatzoglou5, Nadeem Riaz3, Nancy Lee3, and Amita Shukla-Dave1,5

1Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2Radiation Oncology, Dana-Farber/Brigham and Women’s Cancer Center, South Weymouth, MA, United States, 3Radiation Oncology, Memoral Sloan Kettering Cancer Center, New York, NY, United States, 4Radiation Oncology Eye, Ear, Nose & Throat, Hospital of Fudan University, Shanghai, China, 5Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States

The study aims to assess quantitative metrics derived from pretreatment NG-IVIM using multiple b-value diffusion weighted imaging data for predicting tumor with and without locoregional failure (LRF) in NPC patients. Kaplan-Meier method and the log-rank test were used to analyze differences between NPC patients with and without locoregional curves. Kaplan Meier results showed that the pre-treatment mean ADC and D value could predict LRF in NPC patients. The pretreatment NG-IVIM diffusion-weighted imaging will provide useful information for the selection of patients appropriate for definitive radiotherapy.

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Increasing reader confidence in cancer imaging using an advanced DWI processing – a prospective reader study
Constantin Dreher1, Tristan Anselm Kuder2, Stefan Windhaber1, Franziska König1, Daniel Paech1, Anoshirwan Tavakoli1, Regula Gnirs1, Thomas Benkert3, Heinz-Peter Schlemmer1, and Sebastian Bickelhaupt1

1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 3Siemens Healthcare GmbH, Erlangen, Germany

Diffusion-Weighted imaging (DWI) in abdominal MRI is highly valuable for oncological follow-up-investigations. However, intrinsic limitations of the method, including susceptibility to motion artifacts and poor signal in the retroperitoneum, are of special importance regarding its usage in abdominal examinations. This prospective study compared a standard EPI-DWI with an oncologically optimized prototype DWI in 59 patients with regard to the detectability/characterization of suspicious lesions. The study demonstrated that the oncologically optimized prototype DWI sequence with complex averaging, motion correction between averages, rescaling of motion corrupted averages, and background suppression, significantly increased the reader confidence for lesion characterization/detection in oncological abdominal MRI.

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Prospective evaluation of motion correction and complex averaging in ultra-high-b-value DWI for image quality and lesion conspicuity in oncologic follow-up examinations
Constantin Dreher1, Tristan Anselm Kuder2, Stefan Windhaber1, Franziska König1, Daniel Paech1, Anoshirwan Tavakoli1, Regula Gnirs1, Thomas Benkert3, Heinz-Peter Schlemmer1, and Sebastian Bickelhaupt1

1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 3Siemens Healthcare GmbH, Erlangen, Germany

In oncological, abdominal MRI, the value of motion corrected Diffusion-Weighted Imaging (DWI) including complex averaging with high and ultra-high b-values remains to be defined. This is of special importance regarding the balance between normal tissue suppression and suspicious lesion demarcation. This prospective study investigated 41 patients with an oncologically optimized prototype-DWI (with complex averaging, motion correction between averages, rescaling of motion corrupted averages, background suppression). Image quality, tissue differentiation and lesion detection/characterization were significantly increased in high (b900) as compared to ultra-high (b1500) DWI. At the same time, apparent signal-intensity ratio of lesion/normal tissue was not significantly different.

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Whole-volume ADC Histogram and Texture Analyses of Parotid Glands as an Image Biomarker in Evaluating Disease Activity of Primary Sjögren's Syndrome
zhengyang zhou1, Jian He1, and Weibo Chen2

1Radiology, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China, 2Philips Healthcare, Shanghai, China

Fifty-five patients with pSS underwent MRI including DWI to explore whether ADC histogram and texture analyses to evaluate the disease activity of pSS. According to the ESSDAI score, 35 patients were categorized into the low-activity group and 20 into the moderate-high-activity group. ROC analysis showed that the anti-SSB, lip biopsy, MRI morphology, ADC, ADCmean, and entropy values were able to categorize the disease into two groups, particularly the entropy values. The multivariate model, which included anti-SSB, MRI morphology and entropy, had an area under the ROC curve of 0.923. The parotid entropy value distinguished disease activity in patients with pSS.

3448
Computer 111
Non-Gaussian Diffusion Imaging with a Fractional Order Calculus Model to predict response to neoadjuvant chemoradiotherapy in local advanced rectal cancer
Yanfen Cui1, Zhizheng Zhuo2, and Xiaotang Yang1

1Shanxi Province Cancer Hospital, Taiyuan, China, 2MR Clinical Sciences, Philips Healthcare Greater China, Beijing, China

A novel non-Gaussian diffusion model based on fractional order calculus (FROC) were successfully applied to diffusion MRI of rectal cancer. Statistically significant differences in △D and △β values are observed between the responder group and non- responder group (p < 0.01), indicating that FROC-derived parameters from the FROC diffusion model may be useful as imaging biomarkers in predicting the biological properties of rectal cancer in clinical practice.

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Reduced field-of-view Diffusion-weighted imaging at 3T for Evaluating Allograft Fibrosis After Kidney Transplantation: A Preliminary Study
Yuan Meng Yu1, Long Jiang Zhang2, and Yong Zhang3

1Department of Medical Imaging, Jinling Hospital, Nanjing Clinical School, Southern Medical University, Nanjing, China, China, 2Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China, Nanjing, China, China, 3GE Healthcare, Advanced Application, Shangha, China, Shangha, China, China

The extent of renal allograft fibrosis is a critical predictor of adverse allograft outcome. This institutional review board approved study included 109 renal transplantation recipients receiving 3 T multi-b reduced field-of-view intravoxel incoherent motion diffusion-weighted imaging (rFOV IVIM-DWI) examinations. The purpose of the present study is exploring the diagnostic value of evaluating allograft fibrosis with IVIM-DWI. In the present study, we have found that there is downward trend of ADCT and ADCD with the development of kidney fibrosis and both of them had good diagnostic efficiency in the distinguish fibrosis extent.

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Diffusion time-dependence of diffusivity and kurtosis in locally advanced head and neck squamous cell carcinoma before and after chemo-radiation therapy
Gregory Lemberskiy1, Steven Baete1, Dmitry S Novikov1, Els Fieremans1, Elcin Zan1, Kenneth Hu2, and Sungheon Gene Kim1

1Radiology, NYU School of Medicine, New York, NY, United States, 2Radiation Oncology, NYU Langone Health, New York, NY, United States

Synopsis: The effect of chemo-radiation therapy on advanced head & neck squamous cell carcinoma was evaluated via diffusion and kurtosis time-dependence. We found opposing diffusion limiting regimes pre and post therapy, where prior to therapy the tissue was well described by the long-time limit (Karger Model applies), and where after therapy the tissue was well described by the short-time S/V limit. This reversal of imaging regimes can serve as a signature of the minimal effective dose required for treatment. 

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Predicting Renal Glomerular Filtration Rate of Children with Account of Kidney Compensation Using Multiple b Values Diffusion-Weighted Imaging
Jianbo Shao1, Zhiyao Tian1, Xiaowen Wang2, Zujun Hou3, and Xuehua Peng1

1Radiology Department, Wuhan Children's Hospital, Tongji Medical College,Huazhong University of Science&Technology, Wuhan, China, 2Department of Nephrology, Wuhan Children's Hospital, Tongji Medical College,Huazhong University of Science&Technology, Wuhan, China, 3FITPU Healthcare Ltd, Singapore., Singapore

GFR would fail to tell the functional status of each kidney for CKD cases,so we try to use machine learning methods to predict GFR of pediatric kidneys based on the IVIM diffusion parameters. The results is that,With account of kidney compensation, averaged correlation between predicted and measured GFR up to 0.9 (p < 0.05) was obtained for the combination of perfusion-fraction f and pseudo-flow fD*. For comparison, if not taking into account kidney compensation, the best predictor attained the correlation of 0.3. We conclude that a noninvasive method can predict well the GFR of children with kidney diseases using multiple b values DWI. The best predictions involved the use of perfusion-fraction f and pseudo-flow fD* which are closely related to renal blood perfusion.

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The performance of TGSE BLADE DWI in the diagnosis of cholesteatoma compared with RESOLVE DWI technique
Yaru Sheng1, Yan Sha1, Yang Li1, Xinpei Ye1, Zhongshuai Zhang2, Kun Zhou3, Caixia Fu3, and Mengxiao Liu4

1EENT Hospital of Fudan University, Shanghai, China, 22.Scientific Marketing, Siemens Healthcare, Shanghai, China, 3Department of Digitalization, Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China, 4Scientific Marketing, Siemens Healthcare, Shanghai, China

Synopsis:This study aimed to compare the performance of two diffusion weighted imaging techniques used to diagnose cholesteatoma: readout-segmented echo-planar imaging (RESOLVE) and turbo gradient spin echo (TGSE) BLADE DWI.  The results showed that the TGSE BLADE DWI had better image quality with respect to reducing susceptibility artifacts, distortion, and blurring compared with RESOLVE. However, the SNR of TGSE BLADE DWI needs to be improved in the future.

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Head and neck squamous cell carcinoma: diagnostic performance of diffusion kurtosis imaging for the prediction of histopathologic prognostic factors
Tong Su1, Yu Chen1, Zhenyu Jin1, Xiaohua Shi2, Xingming Chen3, Tao Zhang4, Jinxia Zhu5, Robert Grimm6, Huadan Xue1, and Zhuhua Zhang1

1Radiology, Peking Union Medical College Hospital, Beijing, China, 2Pathology, Peking Union Medical College Hospital, Beijing, China, 3Otolaryngology, Peking Union Medical College Hospital, Beijing, China, 4Stomatology, Peking Union Medical College Hospital, Beijing, China, 5Siemens Healthcare Ltd., Beijing, China, 6Siemens Healthcare GmbH, Erlangen, Germany

This preliminary study evaluated the diagnostic efficacy of diffusion parameters, derived from different models, for differentiating between tumor grades and identifying metastatic lymph nodes in head and neck squamous cell carcinomas (HNSCCs). Superior diagnostic efficiency was achieved when combining ADC values derived from a mono-exponential model with kurtosis and diffusivity values derived from a diffusion kurtosis imaging (DKI) model compared to using each parameter by itself.

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Histogram analysis of diffusion kurtosis imaging in prostate cancer: comparison with pathology using in-bore transrectal MR-guided biopsy
Yuwei Jiang1, Lu Yu1, Yadong Cui1, Chunmei Li1, Kaining Shi2, and Min Chen1

1Beijing Hospital, Beijing, China, 2Philips Healthcare, Beijing, China

Our purpose was to verify the use of DKI histogram analysis for differential diagnosis of prostate cancer and noncancerous foci (benign prostatic hyperplasia and prostatitis). Twenty-three patients underwent MRI subsequently using in-bore transrectal MR-guided biopsy as the pathological reference. Our results showed DKI histogram analysis has favorable effective function and good repeatability for the differential diagnosis. DKI histogram analysis may contribute to improve the diagnostic accuracy.

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Quantifying diffusion-weighted MRI parameters with cellular infiltration, tissue ingrowth, and angiogenesis to characterize collagen-sponge remodeling.
Mohammed Salman1,2, Karl Helmer1, Isa Ahmed2, Sivakumar Kandasamy2, Staurt Howes2, Christopher Sotak2, and George Pins2

1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 2Worcester Polytechnic Institute, Worcester, MA, United States

In vivo evaluation of biomaterial implant remodeling involves surgical removal of the implant for subsequent histological assessment, which is often destructive and limits the effective evaluation of these materials. Diffusion-weighted MRI has the potential to non-invasively monitor the remodeling of collagen scaffolds. This study investigated the role of apparent diffusion coefficient (ADC) from different diffusion regimes to evaluate the remodeling of implanted collagen scaffolds and correlated the findings to conventional histological techniques. Correlations between ADC and histological parameters demonstrated that MRI is sensitive to specific remodeling parameters which can aid in the design of robust biomaterial scaffolds for tissue regeneration.

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A Comparative Study of IVIM Model, Kurtosis Model and IVIM-Kurtosis Model for the Diagnosis and Aggressiveness Assessment of Prostate Cancer
Ying Liu1, Chunmei Li1, Kaining Shi2, and Min Chen1

1Beijing Hospital, Beijing, China, 2Philips Healthcare, Beijing, China

The purpose of our study was to quantitatively compare the utility of the parameters obtained from IVIM, kurtosis, and IVIM-kurtosis models in the differential diagnosis and aggressiveness assessment of prostate cancer, by using in-bore transrectal MR-guided biopsy as a reference. Our results displayed that IVIM, kurtosis and IVIM-kurtosis models has effective function for the differential diagnosis of prostate cancer and the diagnostic efficacy among the three models were similar. In aggressiveness assessment, IVIM-kurtosis model may be superior to the others.

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Computer 120
Adapting Diffusion Weighted Arterial Spin Labelling (DWASL) to use a Single Sided Bipolar Diffusion Gradient to Probe Microvascular Signal
Samantha Paterson1, Antoine Vallatos2, and William Holmes3

1Neuroscience & Psychology, University of Glasgow, Glasgow, United Kingdom, 2University of Edinburgh, Edinburgh, United Kingdom, 3University of Glasgow, Glasgow, United Kingdom

Diffusion Weighted Arterial Spin Labelling uses a pair of bipolar diffusion gradients surrounding a spin echo pulse to image signal in the intravascular and extravascular compartments. We propose moving these gradients to a single sided gradient, reducing Δ and changing where the change to the extravascualar signal starts. Our results show that the ratio has changed from b = 50 to b = 300 s/mmfor our new single sided sequence. This can give us more information on the intravascular signal, helping to improve the probing of blood brain barrier permeability.

3458
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Differentiation of Sinonasal Mucosal Malignant Melanomas from Sinonasal Carcinomas Using Whole-tumour Histogram Analysis of Diffusion Kurtosis Imaging and Intravoxel Incoherent Motion
Zebin Xiao1, Zuohua Tang2, Jing Zhang3, Guang Yang3, Yang Song3, Linying Guo2, and Zhongshuai Zhang4

1Eye & ENT Hospital of Fudan University, Shanghai, China, 2Radiology, Eye & ENT Hospital of Fudan University, Shanghai, China, 3Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, 4MR Scientific Marketing, Siemens Healthcare, Shanghai, China

This is the first study that used histogram metrics derived from diffusion kurtosis (DKI) and intravoxel incoherent motion (IVIM) to differentiate sinonasal mucosal malignant melanomas (SNMMMs) and squamous cell carcinomas (SCCs) which are sometimes indistinguishable with conventional MRI. Overall, histogram metrics obtained from K, D, D* and f were found to be significantly higher in SNMMMs than in SCCs. Furthermore, the combined use of the two independent indicators, the 75th percentile of K and skewness of D, can effectively differentiate between SNMMMs and SCCs.

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Quantifying diffusivity of ISFIs in vivo using DWI: A novel method to evaluate drug release
Nicole Vike1, Xin Li2, Kelsey Hopkins2, Luis Solorio2, and Joseph Rispoli2,3

1Basic Medical Sciences, Purdue University, West Lafayette, IN, United States, 2Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 3Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States

Medication effectiveness relies on patient adherence to a given treatment regimen. Often, patients do not adhere to the temporal guidelines set by their physicians and treatments therefore remain less effective. In situ forming implants (ISFIs) eliminate the need for patient adherence and release an effective dose of drug overtime. However, no methods exist to noninvasively and temporally validate drug release in vivo. We conducted in vivo experiments that validated the use of DWI to monitor ISFI diffusivity overtime. This has enormous implications in pharmaceutical research as this method can robustly quantify diffusivity in ISFIs post-implantation to ensure effective drug release.

3460
Computer 123
Evaluation the staging of liver fibrosis using diffusion kurtosis imaging: a pilot study
Jiawei Hu1, Dongmei Guo1, Yang Dong1, Yan Xu2, Bing Wu3, and Lizhi Xie3

1The Second Hospital of Dalian Medical University, Dalian, China, 2The First People’s Hospital of Dalian Jinzhou, Dalian, China, 3GE Healthcare, China, Beijing, China

To investigate the diagnostic value of the quantitative diffusion kurtosis imaging(DKI)parameters in the staging diagnosis of liver fibrosis in rabbits’ model. Twenty-nine successful rabbit models were scanned by a 3T MR scanner (Discovery MR750W, GE,Healthcare, USA). GE AW4.6 Workstation and statistical software helps to evaluate the correlation between quantitative analysis of DKI and METAVIR staging. It is concluded that DKI related parameters might have important diagnostic value for the staging of liver fibrosis.

3461
Computer 124
Assessment of microstructural changes during intervertebral disc degeneration by diffusion kurtosis imaging
Li LI1,2, Jicheng Fang1, Alessandro Scotti,2, Kejia Cai2, and WenZhen Zhu1

1Radiological Department, Tongji Hospital, Tongji Medical College, HUST, Wuhan, China, 21.Radiology Dept., 2. Bioengineering Dept., College of Medicine, University of Illinois at Chicago, Chicago, IL, United States

To assess the microstructural changes of intervertebral disc degeneration, 18 rats were punctured percutaneously at the intervertebral disc, and the rats’ tail was imaged with T2WI, DWI and DKI sequences. The diffusion parameters changes were consistent with the histological changes at the different time points and showed significant differences between the different groups. And, DKI parameters were better markers to detect the change of microstructure of the degenerated discs than conventional DWI. Therefore, DKI is a noninvasive technique to test the changes of the microstructure of the intervertebral discs. 


Diffusion MRI: Signal Representation & Modelling

Exhibition Hall
Wednesday 8:15 - 9:15
 Diffusion

3462
Computer 126
Brain Development in Non-human Primates Assessed with Neurite Orientation Dispersion and Density Imaging
Mayu Iida1,2, Junichi Hata2,3,4, Marin Nishio1,2,3, Fumiko Seki2,3,4, Yawara Haga1,3,4, Erika Sasaki2,3, and Takako Shirakawa1

1Department of Radiological Sciences, Human Health Sciences, Tokyo Metropolitan University Graduate School, Tokyo, Japan, 2Live Imaging Center, Central Institute for Experimental Animals, Kanagawa, Japan, 3Department of Physiology, Keio University School of Medicine, Tokyo, Japan, 4Laboratory for Marmoset Neural Architecture, Center for Brain Science, RIKEN, Saitama, Japan

Neurite orientation dispersion and density imaging (NODDI) can specifically estimate the microstructure of neurites. Brain development characteristics were evaluated using NODDI in common marmosets. The study included six common marmosets (age, 5–30 months). In NODDI, the value of both dispersion and density increased. Additionally, the trend of increase varied from region to region. This pattern has previously been observed in human studies. Thus, NODDI can be a good approach to evaluate brain development in the common marmoset, and eventually a suitable parameter to study brain developmental disorders for diagnosis and treatment.

3463
Computer 127
Diffusion Dispersion Imaging: Mapping OGSE Frequency Dependence in the In Vivo Human Brain
Aidin Arbabi1 and Corey A. Baron1

1Centre for Functional and Metabolic Mapping, Robarts research institute, Western university, London, ON, Canada

Oscillating gradient spin-echo (OGSE) diffusion MRI allows measurement of the frequency dependence of the apparent diffusion coefficient (ADC), which gives insight into tissue microstructure. OGSE has been utilized in numerous animal models, but its application in the in vivo human brain is challenging. Further, a parameterization that allows visualization of maps of the frequency dependence of ADC throughout the human brain has thus-far not been demonstrated. In this work, we report on an efficient method to generate maps of diffusion dispersion (DD), which characterizes the frequency dependence of the ADC, and demonstrate full-brain DD mapping in vivo at 7T.

3464
Computer 128
Correlation Tensor Imaging (CTI): resolving diffusion sources of non-Gaussian diffusion
Rafael Neto Henriques1, Sune N Jespersen2,3, and Noam Shemesh1

1Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal, 2Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Clinical Institute, Aarhus University, Aarhus, Denmark, 3Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark

The cumulant expansion of Double Diffusion Encoding (DDE) involving correlation tensors has been previously theoretically presented but never exploited beyond microscopic anisotropy detection. Here, we propose the correlation tensor imaging (CTI) as novel approach capable of mapping correlation tensor features using DDE acquisitions. The correlation tensor can provide unique information: as a first step, we theoretically and experimentally demonstrate that CTI can be used to resolve the different underlying sources of diffusion kurtosis vis-à-vis isotropic and anisotropic variance of tensors and restricted diffusion (µK). The ensuing estimates bode well for many future applications.

3465
Computer 129
Restricted diffusion in the Gaussian local phase approximation
Lukas Buschle1, Christian Ziener1, Thomas Kampf2, Sabine Heiland3, Martin Bendszus3, Heinz-Peter Schlemmer1, and Felix Kurz3

1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Neuroradiology, University Hospital Wuerzburg, Wuerzburg, Germany, 3Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany

Diffusion MRI is highly influenced by diffusion boundaries created by microscopic cells and blood-filled vessels. The Gaussian phase approximation is a common method to analyze the signal evolution in the presence of diffusion. However, the Gaussian phase approximation exhibits several drawbacks as it is only valid for strong diffusion effects, it does not provide phase information and it yields only the total magnetization. In this work, we generalize the traditional Gaussian phase approximation and solve the mentioned issues. The new Gaussian local phase approximation is then applied to diffusion restricted between two slabs, within a cylinder and within a sphere.

3466
Computer 130
Diffusion kurtosis imaging as an effective predictor of liver function
Daisuke Yoshimaru1, Yasuo Takatsu2, Yuichi Suzuki3, Toshiaki Miyati4, Yuhki Hamada1, Ayumu Funaki1, Ayumi Tabata1, and Chifumi Maruyama1

1Department of Medical Technology, Tokyo Women's Medical University Yachiyo Medical Center, Yachiyo, Japan, 2Department of Radiological Technology, Tokushima Bunri University Faculty of Health and Welfare, Sanuki, Japan, 3Department of Radiological Service, The University of Tokyo Hospital, Hongo, Japan, 4Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan

We evaluated whether DKI analysis as an indicator of liver function can replace laboratory tests. The mean kurtosis value was found to correlate with the Child–Pugh score and the ICG score. However, the correlation between the mean kurtosis valueand the ALBI score was the poorest among these. ADC values correlated with only the ICG score. The mean kurtosis value can be one of predictors for liver function owing to its correlation with typical indicators of liver function by serum data although this method, which shows liver function using DKI alone, cannot completely substitute the laboratory tests.

3467
Computer 131
Single-shell diffusion MRI data with b=1000: which non-tensor models are feasible?
Andrew D Davis1, Geoffrey B Hall2, Benicio N Frey2, Stephen C Strother3, Glenda M MacQueen4, Stefanie Hassel4, Jacqueline K Harris4, Mojdeh Zamyadi5, Stephen R Arnott5, Jonathan Downar6, and Sidney H Kennedy3

1Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON, Canada, 2McMaster University, Hamilton, ON, Canada, 3University of Toronto, Toronto, ON, Canada, 4University of Calgary, Calgary, ON, Canada, 5Rotman Research Institute, Toronto, ON, Canada, 6Krembil Research Institute, Toronto, ON, Canada

Single-shell diffusion data with b=1000 is commonly acquired in clinically focused studies, and fit with a tensor to calculate microstructure parameters, despite that model's limitations. This study fit several multi-compartment models to such data. The most promising models were: (i) two-fiber ball-stick with a single common diffusivity parameter, which provided the most stable results, and (ii) two-fiber ball-zeppelin, which provided low-noise and stable parameter maps and dispersion values with burn-in settings above 20,000 jumps. The default model in bedpostx yielded lower quality results in this data, even with extremely long processing times.

3468
Computer 132
Regularization stabilizes the fit of the two-compartment free water diffusion MRI model
Jordan A. Chad1,2, J. Jean Chen1,2, and Ofer Pasternak3

1Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States

Free water mapping using single-shell diffusion MRI has been proposed by regularizing the ill-posed problem, but the effect of this regularization has yet to be systematically investigated. Here we explore the solution space for the two-compartment free water model. Without regularization, the solution space is flat for one-shell data, and while it has a minimum for two-shell data, this minimum is not particularly steep. Regularizing the fit by exploiting smoothness of the tensor creates a steep minimum in both one- and two-shell data, demonstrating the advantage of regularization.

3469
Computer 133
Optimal subsampling of q-space for Mean Apparent Propagator MRI using a genetic algorithm
L. Tugan Muftuler1,2, Daniel V. Olson3, and Volkan Emre Arpinar2,4

1Department of Neurosurgery, Medical College of Wisconsins, Milwaukee, WI, United States, 2Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States, 3Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 4Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States

Mean Apparent Propagator (MAP) MRI provides a robust analytical framework to estimate the diffusion probability density function (PDF). Several scalar metrics are calculated from the PDF, which might better characterize tissue microstructure compared to conventional diffusion methods. The downside of MAP MRI is the long acquisition times of over an hour. In this study we developed a genetic algorithm (GA) to determine optimal q-space subsampling scheme for MAP MRI that will keep total scan time under 10 minutes, while preserving accuracy. Results show that the metrics derived from the optimized schemes match those from the full set closely.

3470
Computer 134
Quantifying voxel-wise differences between diffusion propagators across multiple MAP-MRI datasets
Alexandru V. Avram1, Adam S. Bernstein2,3, M. Okan Irfanoglu1, Craig C. Weinkauf4, Amber Simmons2, Martin Cota5, Neville Gai6, Neekita Jikaria5, Anita Moses5, L. Christine Turtzo7, Lawrence Latour7, Dzung L. Pham5, John A. Butman6, and Peter J. Basser2

1National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States, 2National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States, 3Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 4Department of Surgery, University of Arizona, Tucson, AZ, United States, 5Center for Neuroscience and Regenerative Medicine, Henry Jackson Foundation, Bethesda, MD, United States, 6Clinical Center, National Institutes of Health, Bethesda, MD, United States, 7National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States

We describe a technique for voxel-wise analysis across multiple mean apparent propagator (MAP) MRI datasets warped using a diffeomorphic tensor-based registration algorithm. By measuring propagators from co-registered MAP datasets with the same MAP basis functions we can directly quantify voxel-wise differences using angular dissimilarity metrics. We show examples from a cohort of healthy volunteers, and from a longitudinal clinical dataset of a patient undergoing carotid endarterectomy. This approach could provide improved sensitivity in the detection and characterization of subtle microstructural tissue changes in cross-sectional group and longitudinal single-subject clinical studies. 

3471
Computer 135
Diffusion kurtosis imaging–derived histogram metrics for prediction of KRAS/NRAS/BRAF mutations in rectal adenocarcinoma: Preliminary findings
Yanfen Cui1, Zhizheng Zhuo2, and Xiaotang Yang1

1Shanxi Province Cancer Hospital, Taiyuan, China, 2MR Clinical Sciences, Philips Healthcare Greater China, Beijing, China

It was revealed that DKI metrics with whole-tumor volume histogram analysis, especially the K75th parameter, yielded more preferable AUC and specificity values for predicting KRAS/NRAS/BRAF mutations than ADC and D values, and thus may potentially serve as an optimal imaging biomarker for the prediction of KRAS/NRAS/BRAF mutations for guiding targeted therapy. 

3472
Computer 136
Differential diagnosis of pathologic grade of hepatocellular carcinoma (HCC) using whole-tumor histogram and texture analysis based on apparent diffusion coefficient (ADC) map
Ying Zhao1 and Ailian Liu1

1The First Affiliated Hospital of Dalian Medical University, Dalian, China

This work aimed for ADC histogram and texture features based strategy to identify poorly differentiated hepatocellular carcinoma (HCC) which may own a high risk of recurrence or metastasis. The results showed that ADC histogram and texture features can discriminate HCC grade. The 95th percentile achieved the best result (AUC: 0.772; sensitivity: 90%; specificity: 72%) on ADC signal intensity map, forming a valuable strategy for clinical practice.

3473
Computer 137
Diffusion tensor imaging of the sciatic and femoral nerves in osteoarthritis of the hip and osteonecrosis of the femoral head
Shigeo Hagiwara1, Wako Yasushi1, Junichi Nakamura1, Miura Michiaki1, Yawara Eguchi2, Yuya Kawarai1, Masahiko Sugano1, Kenoto Nawata1, Kensike Yoshino1, Kenta Konno1, and Satoshi Yo1

1Chiba University, Chiba, Japan, 2Shimoshizu Hospital, Yotsukaido, Japan

 We visualizedsciatic and femoral nerves andcompared the fractional anisotropy (FA) values of the sciatic and femoral nerves in patients with osteoarthritis of the hip (OA) and osteonecrosis of the femoral head (ONFH) using diffusion tensor imaging (DTI). This study indicates thatthe FA values for the sciatic and femoral nerves in patients with OA and ONFH showed no significant differences with normal hips indicating no degeneration or demyelination occurred in either nerve. DTI may be able to differentiate hip diseases from lumbar nerve radiculopathy.

3474
Computer 138
A Simplified Approach for Measuring Tissue ADC: Application to Prostate Diffusion Scans
Stephan E Maier1,2

1Radiology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden, 2Radiology, Brigham and Women's Hospital, Boston, MA, United States

A simplified approach is presented to obtain consistent tissue ADC data, irrespective of diffusion protocol, location within field of view and MR system. Examples of application in prostate diffusion scans are presented. This could greatly facilitate the establishment of suitable cut-off values to differentiate aggressive from indolent disease in prostate cancer, but as detailed in the abstract would entail several other substantial benefits that are universally applicable to diffusion imaging in tissues.

3475
Computer 139
Optimization of b-values for estimation of IVIM D and f
Oscar Jalnefjord1,2, Mikael Montelius1, Göran Starck1,2, and Maria Ljungberg1,2

1Department of Radiation Physics, University of Gothenburg, Gothenburg, Sweden, 2Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden

IVIM parameter estimation restricted to D and f (avoiding D*) has gained increased popularity. In this study we propose a framework for optimization of b-value schemes for this application. We show that optimized b-values schemes contain exactly three unique b-value, regardless of the total number of acquisitions, and that parameter estimation uncertainty can be substantially reduced by the use of the optimized b-value schemes.

3476
Computer 140
Whole-lesion histogram analysis of the apparent diffusion coefficient - a correlation study with histological grade of hepatocellular
Yongsheng Xu1, Haifeng Liu1, Jinkui Li1, Junqiang Lei2, and Shaoyu Wang3

1Radiology, First Hospital of LanZhou University, lanzhou, China, 2First Hospital of LanZhou University, lanzhou, China, 3MR scientific marketing,Siemens healthineers,China, Lanzhou, China

Lately, an increasing number of studies made an effort to investigate the correlation between quantitative analysis of diffusion weighted imaging (DWI) and the histological grade of HCC. However, the optimal ADC parameter for characterization of grade of HCC has yet to be determined. Various investigators have evaluated that ADC value such as the mean ADC and minimum ADC correlate with histological grade of HCC, which were derived from single or several parts slice–based ROIs within tumors. We drew lesions on multiple slices to get more reliable estimate of lesion signal.

3477
Computer 141
Microstructural Variations in Intra-axonal and Extra-axonal Spaces Associated with Punctate White Matter Lesions in Preterm Infants Reveal by White Matter Tract Integrity Metrics
Mengxuan Li1, Xianjun Li1, Qinli Sun1, Miaomiao Wang1, Congcong Liu1, Yannan Cheng1, Xiaocheng Wei2, and Jian Yang1

1Department of Radiology, the First Affiliated Hospital, Xi’an Jiaotong University, Xi'an, China, 2MR Research China, GE Healthcare,Beijing,People's Republic of China, BengJing, China

Punctate white matter lesions (PWML) are common in preterm infants. Extensive microstructural changes were observed previously. However, specific changes related to axons and extra-axonal structures remain to be investigated. White matter tract integrity (WMTI) metrics derived from diffusion kurtosis imaging provide information of intra-axonal or extra-axonal spaces. This study aimed to use these metrics to quantify specific variations associated with PWML. Besides reduced fractional anisotropy and increased radial diffusivity, increased diffusivities in extra-axonal and intra-axonal spaces were found. Furthermore, tortuosity and fiber dispersion decreased obviously. These results suggested that PWML would influence axonal reorganization as well as extra-axonal structural integrity.

3478
Computer 142
The Histogram Analysis of Intravoxel Incoherent Motion-Kurtosis (IVIM-Kurtosis) model for Detection of Prostate Cancer
Lu Yu1, Yuwei Jiang1, Yadong Cui1, Chunmei Li1, Kaining Shi2, and Min Chen1

1Beijing Hospital, Beijing, China, 2Philips Healthcare, Beijing, China

Diffusion-weighted (DW) MR imaging has a great potential in the study of prostate cancer (PCa). We aimed to assess the feasibility and efficacy of intravoxel incoherent motion-kurtosis (IVIM-Kurtosis) model for the differential diagnosis of PCa, benign prostatic hyperplasia and prostatitis (BPH/prostatitis). Thirty-six patients were enrolled and underwent MRI subsequently using in-bore transrectal MR-guided biopsy as the pathological reference. Significant differences were found for D and f values for the differential diagnosis of PCa and BPH/prostatitis, and D median and f median had the highest area under curve. The f, K and D* were correlated with Gleason score (GS) of PCa.

3479
Computer 143
Diffusion Weighted Imaging with Apparent Diffusion Coefficient on the Assessment of Tumor Heterogeneity for the Differentiation of Molecular Subtypes in Breast Cancer
Joao Vicente Horvat1, Olivia Sutton1, Blanca Bernard-Davila1, Elizabeth Morris1, Katja Pinker1, and Sunitha Thakur1

1Memorial Sloan Kettering Cancer Center, new york, NY, United States

The study evaluated the utility of diffusion weighted imaging with apparent diffusion coefficient on the assessment of tumor heterogeneity for the differentiation of molecular subtypes in a population of 91 patients with invasive breast cancer. The authors investigated the use of histogram analysis and visual assessment of tumor heterogeneity for the differentiation of breast cancer subtypes derived via immunohistochemistry surrogates. The results obtained demonstrated that HER-2 enriched tumors had higher ADC values than other tumor subtypes. It was also demonstrated that histogram analysis and visual assessment of tumor heterogeneity could not reliably be used to differentiate tumor molecular subtypes.

3480
Computer 144
Negative-Unlabeled Learning for Diffusion MRI
Phillip Swazinna1, Vladimir Golkov1, Ilona Lipp2, Eleonora Sgarlata2,3, Valentina Tomassini2,4, Derek K. Jones2, and Daniel Cremers1

1Department of Informatics, Technical University of Munich, Garching, Germany, 2CUBRIC, Cardiff University, Cardiff, United Kingdom, 3Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy, 4Division of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom

Machine learning strongly enhances diffusion MRI in terms of acquisition speed and quality of results. Different machine learning tasks are applicable in different situations: labels for training might be available only for healthy data or only for common but not rare diseases; training labels might be available voxel-wise, or only scan-wise. This leads to various tasks beyond supervised learning. Here we examine whether it is possible to perform accurate voxel-wise MS lesion detection if only scan-wise training labels are used. We use negative-unlabeled learning (an equivalent of positive-unlabeled learning) and achieve an AUC of 0.77.

3481
Computer 145
Diagnostic Value of Apparent Diffusion Coefficient for predicting aggressive histological features of papillary thyroid carcinomas
Bin Song1

1Department of Radiology, Minhang Hospital, Fudan University, Shanghai, China

Objective: To investigate the value of preoperative diffusion-weighted magnetic resonance imaging for predicting aggressive histological features in papillary thyroid cancer (PTC). Methods: The mean, minimum apparent diffusion coefficient (ADCmean and ADCmin) and ADC value of the solid component (ADCsolid) were compared among different aggressive histological groups. Analyses of receiver-operating characteristic curve were also performed. Results: The ADC value in the low aggressive PTC were significantly higher than in high aggressive PTC. ADCmin values had the best performance.  Conclusion: ADCmin values derived from DWI could be used as quantitative predictors of aggressive histological features in PTC.

3482
Computer 146
DKI parameter inference by deep neural networks trained by synthetic data
Ko Sasaki1,2 and Yoshitaka Masutani2

1Radiology, Hiroshima Heiwa Clinic, Hiroshima, Japan, 2Graduate School of Information Sciences, Hiroshima City University, Hiroshima, Japan

In general, DKI parameters (D and K) are obtained by fitting models to DWI signal values, such as by least-square fitting (LSF) methods. However, when DWI signal values are contaminated by noise of high level, fitting error is often observed especially for diffusional kurtosis K. In this study, we propose a robust method to infer DKI parameters based on deep neural networks trained by only synthetic data to overcome the limitations of real data training. Our experimental results including comparison with LSF showed the potential of our method for robust inference of DKI parameters.

3483
Computer 147
Framework to Identify Motion-Related Artifacts in Non-Diffusion Weighted Reference Images
Douglas C Dean III1 and Andrew L Alexander1,2

1Waisman Center, University of Wisconsin Madison, Madison, WI, United States, 2Medical Physics, University of Wisconsin Madison, Madison, WI, United States

Motion related artifacts can significantly degrade the quality of quantitative measures estimated from diffusion weighted images. Here, we present a method to identify images with significant motion artifact by inspecting the high and low frequency domain from a 1-D Fourier transform along the phase-encode direction of the data. Our results demonstrate the feasibility of such an approach for identifying images with significant motion artifacts, which can ultimately be used to improve the quality of diffusion parameter estimates. This framework may provide a more objective approach to identify images affected by motion-artifact compared to traditional visual inspection. 

3484
Computer 148
Machine learning can boost the acquisition and estimation of anomalous diffusion model
Boyan Xu1, Yang Fan2, and Jia-Hong Gao1

1Center for MRI Research, Peking University, Beijing, China, 2MR Research China, GE Healthcare, Beijing, China

The departure from mono-exponential decay of the diffusion-induced signal loss has promoted the research of anomalous diffusion in MRI. It has been found that anomalous diffusion models offer substantial advantages over the conventional method in clinical applications. However, these models require more diffusion weightings for complicated estimation procedure, which prevents its further application. In this study, we demonstrated that machine learning can be applied to accelerate the estimation of anomalous diffusion parameters. Furthermore, feature selection was used to identify the most relevant signals, thus helping to reduce the extensive sets of diffusion weightings.

3485
Computer 149
Multi-parametric segmentation of whole-brain variability maps of diffusion MRI metrics
Pedro Angel Luque Laguna1,2,3, Steve Williams1, and Flavio Dell'Acqua2,3

1Neuroimaging, King's College London, London, United Kingdom, 2Forensic and Neurodevelopmental Sciences, King's College London, London, United Kingdom, 3Natbrainlab, London, United Kingdom

The analysis of the whole-brain statistical variability maps corresponding to different statistical coefficients provides quantitative and anatomical information regarding the reproducibility, reliability or biological variability of diffusion MRI data. However, the separate analysis of each statistical map cannot reveal the emerging relationships that exist between these three properties of the data and their interactions across the brain anatomy. In this abstract, we present a new integrated multi-parametric segmentation approach for the combined visualisation and analysis of the reproducibility, reliability and biological variability maps using diffusion MRI data acquired from an older population.

3486
Computer 150
Alteration of IVIM Parameters by Signal Variation of Multiple b-value DWI Measurement
Chun-Jung Juan1, Teng-Chieh Cheng2, Tzu-Cheng Chao3, Teng-Yi Huang4, Chia-Wei Lin1, Wu-Chung Shen1, and Yi-Jui Liu2

1Department of Medical Imaging, China Medical University Hsinchu Hospital, Hsinchu, Taiwan, taichung, Taiwan, 2Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, taichung, Taiwan, 3Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan, Taiwan., tainan, Taiwan, 4Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, taipei, Taiwan

The purpose of this study is to explore the alterations of IVIM measurement among multiple b-value sets with different low b-value and high b-value numbers using EPDWI. EPDWI with 41 different b-values was performed. For simulating the situation in clinic, five sets of 16 b-value numbers were chose from the 41 b values. DWI data of 1000 pixels for each WM, GM and CSF were randomly chose to evaluate the error of IVIM parameters. Our study demonstrated the variation of DWI signal with multi-b-value, affect the evaluation of Df and f but does not affect Ds in pixel-wise IVIM analysis.


Diffusion MRI: Diffusion Gradient Waveform Design & Optimization

Exhibition Hall
Wednesday 8:15 - 9:15
 Diffusion

3487
Computer 151
Optimal selection of diffusion-weighting gradient waveforms using compressed sensing and dictionary learning
Raphaël Malak Truffet1, Christian Barillot1, and Emmanuel Caruyer1

1Univ Rennes, CNRS, Inria, Inserm, IRISA - UMR 6074, VisAGeS - ERL U 1228, F-35000 Rennes, France, Rennes, France

Acquisition sequences in diffusion MRI rely on the use time-dependent magnetic field gradients. Each gradient waveform encodes a diffusion-weighted measure; a large number of such measurements are necessary for the in vivo reconstruction of microstructure parameters. We propose here a method to select only a subset of the measurements while being able to predict the unseen data using compressed sensing. We learn a dictionary using a training dataset generated with Monte-Carlo simulations; we then compare two different heuristics to select the measures to use for the prediction. We found that an undersampling strategy limiting the redundancy of the measures allows for a more accurate reconstruction when compared with random undersampling with similar sampling rate.

3488
Computer 152
Reduced Eddy Current induced image distortions and Peripheral Nerve Stimulation based on the Optimal Diffusion-weighting Gradient Waveform Design (ODGD) formulation
Óscar Peña-Nogales1, Yuxin Zhang2,3, Rodrigo de Luis-Garcia1, Santiago Aja-Fernández1, James H. Holmes3, and Diego Hernando4

1Universidad de Valladolid, Valladolid, Spain, 2Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, 3Radiology, University of Wisconsin-Madison, Madison, WI, United States, 4University of Wisconsin-Madison, Madison, WI, United States

Diffusion-Weighted MRI (DW-MRI) often suffers from signal attenuation due to long TE, motion-related artefacts, dephasing due to concomitant gradients (CGs), and image distortions due to eddy currents (ECs). Further, the application of rapidly switching gradients may cause peripheral nerve stimulation (PNS). These challenges hinder the progress, application and interpretability of DW-MRI. Therefore, based on the Optimized Diffusion-weighting Gradient waveforms Design (ODGD) formulation, in this work we design optimal (minimum TE) nth-order moment-nulling diffusion-weighting gradient waveforms with or without CG-nulling able to reduce EC induced distortions and PNS-effects. We assessed the feasibility of these waveforms in simulations and phantom experiments.

3489
Computer 153
Silent Distortionless DWI
Jianmin Yuan1, Yuxin Hu1,2, Anne Menini3, Christopher M. Sandino2, Jesse Sandberg4, Marcus Alley1, Michael Lustig5, Brian Hargreaves1, and Shreyas Vasanawala1

1Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States, 3GE Healthcare, Menlo Park, CA, United States, 4Pediatric Radiology, Lucile Packard Children’s Hospital, Stanford University, Stanford, CA, United States, 5Electrical Engineering and Computer Science, UC Berkeley, Berkeley, CA, United States

Standard clinical EPI based diffusion sequence has high acoustic noise, which is uncomfortable for patients. The images acquired by single-shot EPI also suffer from distortion in areas of large susceptibility variations. To overcome these two limitations, we have developed a silent and distortion-free DWI sequence using a driven equilibrium diffusion prepared multi-segmented Rotating Ultra-Fast Imaging Sequence (RUFIS) readout. The sequence was validated in phantom, volunteers, and patients. The results showed the proposed sequence provides similar diffusion contrast and ADC measurement compared to DW-EPI, with improved image quality and a sound level that approaches that of ambient noise.

3490
Computer 154
The tuned trinity of b-tensors
Samo Lasič1, Henrik Lundell2, and Daniel Topgaard3

1Random Walk Imaging, Lund, Sweden, 2Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark, 3Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden, Lund, Sweden

Unprecedented microstructural details of heterogeneous materials such as tissue are non-invasively accessible by multidimensional diffusion encoding (MDE) MRI using varying shapes of b-tensors. MDE can probe multidimensional distributions of diffusion tensors in terms of their size, shape and orientation. For robust conclusions, time-dependent diffusion effects need to be considered in MDE. A convenient recipe for generating b-tensors of varying shape was implemented including a single adjustable tuning parameter. The resulting b-tensors can thus be tuned for sensitivity to time-dependent diffusion.

3491
Computer 155
An accurate surface-to-volume ratio estimation by general diffusion gradient waveform
Nicolas Moutal1, Ivan I. Maximov2,3, and Denis S. Grebenkov1

1Laboratoire PMC, Ecole Polytechnique, Palaiseau, France, 2NORMENT, KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Oslo, Norway, 3Institute of Clinical Medicine, University of Oslo, Oslo, Norway

We generalize Mitra’s formula for estimating the surface-to-volume ratio of an anisotropic medium with any pore shapes by using arbitrary diffusion gradient waveforms. We show that the surface-to-volume ratio can be significantly misestimated using the original formula without taking into account the applied diffusion gradient profile. For an accurate estimation, we derive new “isotropy” criteria which ensure that the diffusion weighted sequence is insensitive to the mesoscopic anisotropy of the sample. As a result, we introduce a novel class of porous media characteristics which are useful for biomedical applications.

3492
Computer 156
Optimized diffusion gradient waveforms for estimating surface-to-volume ratio of an anisotropic medium
Nicolas Moutal1, Ivan I. Maximov2,3, and Denis S. Grebenkov1

1Laboratoire PMC, Ecole Polytechnique, Palaiseau, France, 2NORMENT, KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Oslo, Norway, 3Institute of Clinical Medicine, University of Oslo, Oslo, Norway

We present here a simple and efficient algorithm for designing of diffusion gradient profiles allowing one to implement prescribed theoretical properties. This algorithm generalizes the well-known sine and cosine decomposition and can handle various experimental constraints. Relying on recent diffusion MRI theoretical advances, we apply it to the challenging problem of estimating the surface-to-volume ratios in anisotropic media.

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Oscillating Gradient Spin-Echo Diffusion Tensor Imaging of the Human Brain using FLAIR
Fernanda Padron1, Thorsten Feiweier2, and Christian Beaulieu1

1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada, 2Siemens Healthcare GmbH, Erlangen, Germany

Oscillating-gradient spin-echo (OGSE) diffusion tensor MRI permits very short diffusion times (e.g. 5 ms) relative to the typical pulsed-gradient spin-echo (PGSE), but it is challenging to acquire in the human brain. Given low b-values and spatial resolution, it is more prone to problematic artifacts such as Gibbs ringing and partial-volume effects that can compromise diffusion parameter measurements. It is shown here that the use of inversion-recovery FLAIR to suppress cerebrospinal fluid can significantly reduce such artifacts, improve overall image/map quality, and provide better quantitation of OGSE-PGSE diffusion parameter differences in the white matter of the human brain.

3494
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Impact of different b-value combinations on Radiomics Features of Apparent Diffusion Coefficient in Cervical Cancer
Zilong Yuan1, Yaoyao He2, Yi Rong3, Hao Chen1, Zhaoxi Zhang1, Jianfeng Qiu2, Lili Zheng1, Stanley Benedict3, and Yulin Liu1

1Department of Radiology, Hubei Cancer Hospital, Wuhan, China, 2Medical engineering and technology center, Taishan Medical University, Taian, China, 3Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, CA, United States

There is potential influence of different b-value combinations on evaluation of ADC-based radiomics features. The aim of this study is to investigate the difference between ADC-based radiomics feature extracted from ADC maps with different b-value combinations in cervical cancer. It was found that variable b-value combinations can play substantially impact on radiomics features extracted from corresponding ADC maps in cervical cancer. Therefore, we should pay more attention to the choice of b-value combinations in retrospective and multi-center studies.

3495
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A Real-time Solver for Convex Optimization of Diffusion Encoding Gradient Waveforms
Michael Loecher1, Matthew Middione1, Kévin Moulin1, and Daniel Ennis1

1Radiology, Stanford University, Stanford, CA, United States

Recent work has demonstrated the usefulness of designing time optimal gradient waveforms for diffusion encoding, especially when incorporating gradient moment nulling to mitigate bulk motion artifacts. Prolonged optimization times, however, can limit the usability of these methods.  This work presents a solver fast enough to run in real-time, and investigates the performance over a range of parameters and tests for convergence. The solver is able to generate diffusion encoding gradient waveforms with gradient moment nulling in 5-50 ms – fast enough to permit real-time optimization on the scanner.

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Impact of Residual Gradient Moments on Diffusion Weighted Imaging
Matthew J. Middione1, Michael Loecher1, Kévin Moulin1, and Daniel B. Ennis1

1Radiological Sciences Lab, Department of Radiology, Stanford University, Stanford, CA, United States

Bulk motion corrupts diffusion measurements in the heart but can be mitigated by nulling first and second gradient moments. When using optimization methods to design diffusion gradient waveforms with moment nulling, imperfect gradient waveforms arise from discrete convergence criteria, which impart residual (non-zero) gradient moments. This leads to intravoxel dephasing, signal loss, and inaccurate ADC measurements. Herein, simulations show that residual M0≤10-2mT/m•s, M1≤10-4mT/m•s2, and M2≤10-5mT/m•s3 leads to ≤5% increase in ADC. This work defines convergence criteria requirements for residual gradient moments that enable faster optimizations and more accurate measurements of ADC when using optimization methods for cardiac DWI sequence design.

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In-vivo cardiac DTI: Comparison between Motion Compensated Optimized Diffusion Encoding (MODE) and Convex Optimized Diffusion Encoding (CODE) Techniques
Prateek Kalra1, Waqas Majeed1, Mohammad R. Maddah1, Xiaokui Mo2, Richard D. White1, and Arunark Kolipaka1

1Radiology, Ohio State University Wexner Medical Center, Columbus, OH, United States, 2Center for Biostatistics, Ohio State University Wexner Medical Center, Columbus, OH, United States

Diffusion-weighted imaging(DWI) is used to determine defective areas such as fibrosis in the myocardium without the need of contrast agent by calculating apparent diffusion coefficient(ADC) and fractional anisotropy(FA). However, DWI of heart is very challenging due to bulk motion to which diffusion encoding gradients are sensitive. Previous studies proposed CODE (convex optimized diffusion encoding) and MODE (Motion-compensated Optimized Diffusion Encoding). Aim of this study is to compare ADC and FA using MODE and CODE technique in healthy subjects. No significant difference was found between two techniques. However, for a given TE, MODE generated slightly higher b-value compared to CODE.  

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Using symmetrized temporal gradient profiles for water diffusion pore imaging on a 14.1 T spectrometer
Dominik Ludwig1,2, Frederik Bernd Laun3, Karel D. Klika4, Peter Bachert1, and Tristan Anselm Kuder1

1Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Institute of Radiology, University Hospital Erlangen (FAU), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, 4Molecular Structure Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany

Diffusion pore imaging can be used to retrieve the pore-space function of an arbitrary closed pore. While a few publications involving pore imaging using the long–narrow gradient approach exist [1–3], all of them involve the use of sophisticated acquisition schemes like CPMG or involve an additional readout gradient. In this study, we were able to show that it is indeed possible to acquire the pore space function of capillaries with a diameter of 15 µm using a simple modification of the long–narrow gradient scheme on a 14.1 T NMR spectrometer.

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A novel approach to diffusion phase imaging using non-linear gradients in anisotropic media
Pamela Wochner1, Jason Stockmann2, Torben Schneider3, Jack Lee1, and Ralph Sinkus1

1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, 2Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, United States, 3Philips Healthcare UK, Guildford, Surrey, United Kingdom

Classical methods for Diffusion-Weighted MRI use linear gradients to obtain information about tissue microstructure encoded in the loss of MR magnitude. These linear gradients cause diffusing spins to dephase which prevents the use of phase information. When, however, gradient fields are applied that vary quadratically in space, diffusion in anisotropic media results in a shift of net phase with only a minimal loss in signal magnitude enabling the exploration of MR phase. Both the theory of this new concept and Monte-Carlo simulations predict net phase for diffusion experiments using quadratic gradients in anisotropic media in excellent agreement.

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Optimizing Diffusion MRI for Mapping Cortical Fiber Patterns
Grant Kaijuin Yang1, John Cocjin1, and Jennifer McNab1

1Stanford University, Stanford, CA, United States

A custom DW pulse sequence is optimized to minimize echo time and evaluate optimal trade-offs between SNR, b-value and spatial resolution for mapping cortical fiber patterns. Using a lower b-value (500 vs. 1000 s/mm2) failed to improve estimates of the principal fiber orientation in the cortex despite the significant boost in signal. Accurate estimates of the principal fiber orientation in the cortex requires a spatial resolution of 1.44 mm isotropic or less. 

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Computer 165
Motion-Robust and Distortion-Corrected Diffusion MR Imaging of the Liver with Optimized Motion-Compensated Waveforms and Multi-shot EPI acquisition
Yuxin Zhang1,2, Ruiqi Geng1,2, Arnaud Guidon3, James H Holmes2, and Diego Hernando1,2

1Medical Physics, University of Wisconsin Madison, madison, WI, United States, 2Radiology, University of Wisconsin Madison, madison, WI, United States, 3Applications and Workflow, GE Healthcare, Boston, MA, United States

Conventional liver diffusion MRI acquisitions suffer from several challenges including low spatial resolution, B0-induced distortions, and elastic motion-induced signal voids. In this work, motion-robust and distortion-corrected liver diffusion-weighted imaging (DWI) was enabled by combining optimized motion compensated diffusion waveforms with multi-shot EPI acquisitions. Diffusion-weighted images of healthy volunteers were acquired to evaluate the effect of motion compensation and distortion correction. Preliminary results demonstrate the feasibility of the proposed approach, including reduced ADC bias in the left lobe (due to the motion-robust waveforms) and reduced distortion (due to the multi-shot acquisition) compared to conventional liver DWI.

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Towards clinically viable and robust measurement of microscopic diffusion anisotropy
Nico J. J. Arezza1,2, Aidin Arbabi2, and Corey A. Baron1,2

1Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada, 2Centre for Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ON, Canada

In contrast to fractional anisotropy, microscopic diffusion anisotropy allows measurement of pore structural anisotropy with no influence from orientational coherence. However, acquisitions that allow in vivo measurement of microscopic anisotropy are generally time-consuming and/or low SNR. Here, we introduce an efficient approach to perform isotropic diffusion encoding and measure high quality full-brain microscopic anisotropy in a scan time of only 3 minutes at 7T. Results are demonstrated in a healthy subject and MS patient, where clear delineation of lesions is observed in the latter case.

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Reducing spectral anisotropy in isotropic b-tensor multidimensional diffusion encoding
Henrik Lundell1, Markus Nilsson2, Filip Szczepankiewicz3,4,5, Carl-Fredrik Westin3,6, Daniel Topgaard7, and Samo Lasič8

1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 2Clinical Sciences, Department of Radiology, Lund University, Lund, Denmark, 3Brigham and Women’s Hospital, Boston, MA, United States, 4Harvard Medical School, Boston, Denmark, 5Department of Radiology, Lund University, Lund, Denmark, 6Harvard Medical School, Boston, MA, United States, 7Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden, 8Random Walk Imaging AB, Lund, Sweden

Multidimensional diffusion encoding isotropic b-tensors eliminate rotational variance from anisotropic Gaussian diffusion, an essential feature for estimating microscopic anisotropy. In anisotropic substrates which exhibit non-Gaussian diffusion on the time scale of the encoding pulse, the variance in temporal characteristics of diffusion encoding across different directions – spectral anisotropy (SA) - may introduce a directional variance in apparent diffusivities. We propose an alternative isotropic encoding with drastically lower SA, which in turn allows accessing intrinsic signatures of non-Gaussian diffusion. 

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Diffusion MRI of the Brain with a Gradient Strength of 100 mT/m and a Slew Rate of 1200 T/m/s
Bertram Wilm1, Manuela Roesler1, Franciszek Hennel 1, Markus Weiger1, and Klaas Pruessmann1

1Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland

The performance of diffusion-weighted single-shot EPI is limited by off-resonance artifacts and low signal-to-noise. To address both problems, we employ a recently developed gradient insert (strength: 100 mT/m, slew rate: 1200 T/m/s). Thereby the time for the diffusion encoding as well as the EPI readout train duration can be significantly shortened, resulting in higher signal yield and robustness against off-resonance artifacts. First in-vivo results are presented.

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3D distortion-free multi-slab diffusion-prepared magnitude-stabilized bSSFP imaging
Yu Gao1,2, Ziwu Zhou1, Xinyu Ye3, Hua Guo3, Yingli Yang2,4, and Peng Hu1,2

1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, 2Physics and Biology in Medicine IDP, University of California, Los Angeles, Los Angeles, CA, United States, 3Biomedical Engineering, Tsinghua University, Beijing, China, 4Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States

A 3D diffusion-prepared magnitude-stabilized bSSFP (DP-MS-bSSFP) sequence was proposed and validated to achieve high resolution distortion-free brain diffusion imaging. Shot-to-shot phase variation was corrected using the plane-by-plane MUSE technique. High-quality 3D diffusion images, ADC maps and cFA maps were obtained from four volunteers. Good agreement of white matter ADC between DW-ssEPI and DP-MS-bSSFP was observed based on the Bland-Altman plot. Geometric accuracy of DP-MS-bSSFP was confirmed by a four-fold reduction of target registration error compared with DW-ssEPI. In conclusion, the proposed DP-MS-bSSFP approach provided high-quality 3D diffusion images and diffusion tensor images with high ADC accuracy and minimal distortion. 

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In-vivo Diffusion Exchange Spectroscopy (DEXSY), to measure water exchange in tumours.
James Olav Breen-Norris1,2, Bernard Siow1,2,3, Claire Walsh1, Mark F. Lythgoe1, Andrada Ianus2, Daniel C. Alexander2, and Simon Walker-Samuel1

1Centre for Advanced Biomedical Imaging, Division of Medicine, UCL, London, United Kingdom, 2Microstructure Imaging Group, Centre for Medical Image Computing, Department of Computer Science, UCL, London, United Kingdom, 3The Francis CRICK institute, London, United Kingdom

We describe the first use of Diffusion Exchange Spectroscopy (DEXSY) in-vivo, to measure water exchange in tumours. We present preliminary data suggesting that we can capture information about the micro-structure of tumors, with what appear to be intracellular, extracellular and perfusion peaks present in diffusion-diffusion exchange plots, acquired from subcutaneous tumor xenograft models, in-vivo using DEXSY.

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Effects of Diffusion Gradient Waveforms on Time-dependent Kurtosis and Microstructural Properties
Dan Wu1,2 and Jiangyang Zhang3

1Biomedical Engineering, Zhejiang University, Hangzhou, China, 2Radiology, Johns Hopkins University School of Medicine, BALTIMORE, MD, United States, 3Radiology, New York University School of Medicine, New York, NY, United States

Diffusion-time (td) dependent diffusion MRI is a promising tool to probe tissue microstructure. Although different diffusion gradient waveforms (DGW) have been introduced to achieve short and long td’s, whether they have comparable sensitivity to microstructural changes remains to be investigated. Here, we examined the td-dependency of kurtosis measured using pulsed, bipolar, and oscillating gradients with different microstructural substrates. Simulations and in vivo experiments showed that the choice of DGW affects the characteristics of time-dependent kurtosis, and this effect varied with microstructural size and permeability. This knowledge is important for design of td-dependent diffusion MRI experiments.

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The optimal b value study of endogenous water molecule diffusion imaging in the diagnosis of brain tumors
Fen Xing1 and Guangyao Wu2

1RenMin hospital of Wuhan University, Wuhan, China, 2Zhongnan Hospital of Wuhan University, Wuhan, China

In this study, thirty-six cases of meningioma were divided into benign and malignant meningioma. ADC values fitted by 11 b values and any pairs of two b values were used to distinguish between benign and malignant meningioma. We found that, the ADC values of benign, malignant, and all meningiomas showed a decreasing trend with the increase of b value, and the smaller the b value, the greater the decrease. when the b value was ≥ 200 s/mm2, any combinations of b values could discriminate between benign and malignant meningioma. The ADC values obtained by fitting b = 700 and b = 1000 s/mm2 had the highest AUC value.  


Diffusion MRI: Data Acquisition

Exhibition Hall
Wednesday 9:15 - 10:15
 Diffusion

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Computer 1
Sub-Millimeter Isotropic DTI and fiber tractography of the human Spinal Cord in-vivo
Iain P Bruce1, Christopher Petty1, and Allen W Song1

1Duke University Medical Center, Durham, NC, United States

The ability to characterize complex microstructures in the small cross-sectional area of the spinal cord through diffusion tensor imaging has traditionally been limited by the achievable spatial resolution in-vivo. Through ultra-high spatial resolution diffusion imaging, this study presents a technique for accurately delineating complex fiber pathways such as the corticospinal tracts. When imaged with sub-millimeter isotropic spatial resolutions, it is possible to characterize intricate details in the spinal cord such as the bifurcations and decussations of the corticospinal tracts. The improved delineation of neural pathways in the spinal cord could facilitate the placement of stimulation electrodes for movement disorder treatments. 

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Multi-Echo Segmented Diffusion-Weighted MRI for Ex-Vivo Whole-Brain Measurements with 300mT/m Gradients
Cornelius Eichner1, Toralf Mildner1, Michael Paquette1, Torsten Schlumm1, Catherine Crockford2, Roman Wittig2, Evgeniya Kirilina1, Carsten Jäger1, Harald E. Möller1, Nikolaus Weiskopf1, Angela Friederici1, and Alfred Anwander1

1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany

We provide a novel method to increase SNR of segmented diffusion-weighted EPI acquisitions. Multiple gradient echoes were acquired after each diffusion-preparation and combined in an SNR-optimized way using weightings from quantitative T2* maps. The combination of diffusion-weighted echoes yielded an SNR-gain of 58% compared to single-echo dMRI data with an increase in the segmented readout duration by only 23.1 ms. The multi-echo diffusion MRI acquisition and combination were employed to acquire high-quality ex-vivo diffusion-weighted MRI data from a wild chimpanzee brain. 

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A Multi-Echo Stejskal-Tanner EPI Sequence for Rapid Measurements of T2 and Diffusion Tensor Correlations
Richard Buschbeck1, Ezequiel Farrher1, Kuan-Hung Cho2, Ming-Jye Chen2, Seong Dae Yun1, Chang-Hoon Choi1, Li-Wei Kuo2,3, and N. Jon Shah1,4,5,6

1Institute of Neuroscience and Medicine 4, Jülich Research Centre, Jülich, Germany, 2Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan, 3Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan, 4Department of Neurology, RWTH Aachen University, Aachen, Germany, 5Institute of Neuroscience and Medicine 11, Jülich Research Centre, Jülich, Germany, 6JARA - BRAIN - Translational Medicine, Aachen, Germany

Initial phantom and in vivo results of a multi-echo Stejskal-Tanner EPI sequence are presented demonstrating the feasibility of rapid measurements for diffusion tensor and T2 correlations. The diffusion and T2 maps are artefact-free and are found to be  very similar to the ones derived from the conventional individual-echo methods. However, the data tend to display slightly overestimated diffusivities and T2, which need to be investigated further.

Compared to the standard method, the proposed multi-echo sequence reduces the scan time by a factor of five, which is necessary to make multidimensional diffusion techniques feasible in clinical settings.


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Effects of imperfect slice separation in simultaneous multi-slice for diffusion kurtosis imaging
L. Tugan Muftuler1,2, Daniel V. Olson3, Volkan Emre Arpinar2,4, and Andrew S. Nencka2,4

1Department of Neurosurgery, Medical College of Wisconsins, Milwaukee, WI, United States, 2Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States, 3Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 4Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States

Simultaneous multislice (SMS) technique accelerates MRI data acquisition. However, slice separation in reconstruction is imperfect. This results in residual leakage between the simultaneously excited slices. For diffusion MRI, repeated pairing of the same slices in the image series leads to repeated leakage of a consistent diffusion signal from the other slice. Studies of this effect on diffusion MRI is sparse. Here, we tested two different SMS acquisition and image reconstruction techniques and quantified resulting errors on all diffusion kurtosis (DKI) metrics in different ROIs. Large errors were observed with SMS compared to singleband acquisitions for all DTI and DKI metrics

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Evaluation of Diffusion-Weighted Readout-Segmented EPI in Macaque Brain Imaging at 7T
Pinyi Wang1, Jialu Zhang1, Meizhen Qian1,2, Yi Sun3, Robin M. Heidemann4, Ruiliang Bai1, Dingxin Wang5, and Xiaotong Zhang1

1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, College of Biomedical Engineering & Instrument Science, Zhejiang University, HangZhou, China, 2School of Medicine, Zhejiang University, Hangzhou, China, 3MR Collaboration Northeast Asia, Siemens Healthcare, Shanghai, China, 4Siemens Healthcare GmbH, Erlangen, Germany, 5Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

    Diffusion-weighted imaging (DWI) has been widely used in brain structure and connectivity investigations and other neuroscience applications. To implement an optimized protocol for high spatial resolution DW imaging at ultra-high field, we have conducted macaque brain imaging by using readout segmented echo planar imaging at 7T. Our results indicate that, the rsEPI has potential to achieve DWI with improved signal-to-noise ratio and with the intent of minimizing geometric distortion.




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A model free, sparse acquisition approach (« Sindex ») to investigate brain tissue microstructure from diffusion MRI data in the human brain
Denis Le Bihan1,2,3, Tetsuya Yamamoto2, Masaki Fukunaga2, Tomohisa Okada3, and Norihiro Sadato2

1NeuroSpin/Joliot, CEA-Saclay, Gif-sur-Yvette, France, 2System Neuroscience, National Institute for Physiological Sciences, Okazaki, Japan, 3Graduate School of Medicine, Human Brain Research Center, Kyoto University, Kyoto, Japan

Diffusion MRI provides noninvasively information of tissue microstructure. Current models allow to empirically analyze data or to provide more insightful information on the tissue features. However, those models require strong assumptions on the underlying tissues and the acquisition of large image data sets with different acquisition parameters. We have investigated a new, model free approach which enables classification of tissue types from the “proximity” or resemblance of their diffusion MRI signal profile at a sparse set of key b values (maximizing sensitivity to tissue microstructure) to a library of “signature” signal profiles (e.g. typical brain grey and white matter).

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Maximising Repeatability: It’s Time to Reconsider the Sampling Scheme for IVIM
Callie Deng1, Pål Erik Goa2, Matthew R. Orton3, Torill E. Sjøbakk1, Tone F. Bathen1, and Neil Peter Jerome1,4

1Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway, 2Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway, 3Division of Radiotherapy & Imaging, Cancer Research UK Cancer Imaging Centre, London, United Kingdom, 4Clinic of Radiology and Nuclear Medicine, St. Olavs University Hospital, Trondheim, Norway

Diffusion-weighted imaging (DWI) has the potential to improve characterisation and detection of breast cancer. A variety of models are available to fit the relationship between MRI signal and b-value, but the repeatability of such models is often overlooked. In this study, we simulate repeated DWI scans and quantify the precision of IVIM parameters from segmented fitting for D and f; our findings suggest that repeatability of f is highly dependent on disproportionate noise at b=0, and repeatability for f and D can be maximised by redistribution of signal averages. Optimal acquisition strategies for varying values of inter-scan noise are reported.

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TRACTOGRAPHY OF THE TRIGEMINAL NERVE OUTSIDE THE BRAIN
Sulagna Sahu1, Munish Chauhan1, Stephen Helms Tillery1, Vikram D. Kodibagkar1, and Rosalind J. Sadleir1

1SBHSE, Arizona state university, Tempe, AZ, United States

Diffusion Tensor Imaging (DTI) tractography used for the visualization of cranial nerves has mostly focused on tracts inside the brain. This work focuses on tracking trigeminal nerve branches using DTI outside the brain. Trigeminal nerve efferents in the face can be stimulated using transdermal electrical neuromodulation. Locations of subcutaneous tracts of the ophthalmic and maxillary branches of the trigeminal nerve may assist with electrode placement in these studies. Here, we describe use of HARDI-derived DTI to determine locations of trigeminal nerve projections in the face.

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Time-efficient high resolution diffusion weighted SSFP measurements at 14.1T
Dario Bosch1,2, Gisela Hagberg1,2, Rolf Pohmann1, Thomas Shiozawa-Bayer3, Bernhard Hirt3, and Klaus Scheffler1,2

1High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany, 3Institute for clinical anatomy and cellanalysis, Department of Anatomy, University Hospital Tübingen, Tübingen, Germany

This study investigates the use of diffusion weighted SSFP imaging for high-resolution diffusivity measurements of post-mortem tissue, using two different models (Wu-Buxton and Freed) and draws a comparison to conventional DW SE-Measurements. A toolbox was developed to optimize SSFP imaging parameters for selected tissue regions which was then used successfully. We showed that the SSFP approach is highly valuable for time-efficient high-resolution post-mortem diffusion weighted imaging.

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Feasibility of 129Xe MRI Morphometry Measurements with Acceleration Factors of 7 and 10
Alexei Ouriadov1, Andrew Ross Westcott1,2, David G McCormack3, and Grace Parraga1,2,3

1Robarts Research Institute, London, ON, Canada, 2Department of Medical Biophysics, Western University, London, ON, Canada, 3Division of Respirology, Department of Medicine, Western University, London, ON, Canada

Hyperpolarized gas pulmonary MRI provides physiologically relevant biomarkers of obstructive lung disease including emphysema, bronchopulmonary dysplasia, congenital lobar emphysema and alpha-1 antitrypsin deficiency. Recently, a stretched-exponential-model combined with under-sampling in the imaging and diffusion direction was used for the generation of 3He static-ventilation, T2* and multiple b-value diffusion-weighted MRI-based ADC/morphometry maps.  We hypothesize that the 3He method can be modified to provide whole lung 129Xe MRI-based emphysema biomarkers including static-ventilation, T2*/ADC/morphometry maps with high-spatial-image-resolution in a single breath-hold. Therefore, in this proof-of-concept evaluation, our objective was to demonstrate a feasibility of this approach in a small group of patients.

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3D distortion-free diffusion imaging using an accelerated multi-shot diffusion-prepared sequence
Elisa Roccia1, Radhouene Neji1,2, Vicky Goh3, and Isabel Dregely1

1Biomedical Engineering, King's College London, London, United Kingdom, 2Siemens Healthcare, Frimley, United Kingdom, 3Cancer Imaging, King's College London, London, United Kingdom

Current methods for cancer diffusion imaging employ 2D single-shot diffusion weighted echo planar imaging sequences, which are fast but have limited resolution and are prone to distortion artefacts. The purpose of this work is to achieve 3D high-resolution and distortion-free diffusion imaging suitable for cancer precision diagnostics and therapy planning. A multi-shot diffusion-prepared sequence with gradient echo readout, centric encoding, and accelerated variable density acquisition was developed and tested in healthy volunteer brains as an exemplar. A full set of 2.2-fold accelerated diffusion weighted images in three diffusion directions was acquired in 4:30 min producing quantitative 3D distortion-free ADC maps.

3520
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Diffusion-Weighted ZOOM-EPI with Simultaneous Multi-Slice Imaging
Jürgen Finsterbusch1 and Caspar Florin1

1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Zonal oblique multi-slice (ZOOM) EPI uses cross-sectional RF excitations to focus the measurement volume to a small, inner volume which allows to reduce the FOV without aliasing in the phase-encoding direction. Thus, geometric distortions are reduced and the spatial resolution of diffusion-weighted acquisitions can be increased as has been demonstrated for the optic nerve and spinal cord. In this study, ZOOM-EPI is combined with simultaneous multi-slice (SMS), the boundary condition to avoid unwanted signal contributions is determined, and the feasibility to shorten acquisitions times is demonstrated for diffusion-tensor imaging (DTI) of the human spinal cord.

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Improvement of EPI-based DWI of the head/neck region using additional local shim coils at 3 Tesla
Sven Stephan Walter1, Regine Perl1, Mike Notohamiprodjo1, Konstantin Nikolaou1, and Sergios Gatidis2

1Department for Diagnostic and Interventional Radiology, University Hospital Tuebingen, Tuebingen, Germany, 2Department for Diagnostic and Interventional Radiology, Univeristy Hospital Tuebingen, Tuebingen, Germany

Implementing additional local shim coils into the head and neck surface coil may enhance the performance of EPI-based diffusion weighted imaging of the head/neck region at 3 Tesla. Thus, we evaluated single shot echo planar DWI and standard T1-weighted gradient echo acquisition without and with the use of additional local shim coils. In addition, apparent diffusion coefficients were quantified in specific anatomical regions. Local shim coils improved the homogeneity of the static magnetic field, resulting in marked improvement of image quality, signal loss, distortion and fat saturation. ADC values did not significantly differ between the measured anatomical compartments.

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A novel Multishell Acquisition with Increased b-Shells and Sparse ORientations (MAISSOR)
Manish Amin1 and Thomas Mareci2

1Physics, University of Florida, Gainesville, FL, United States, 2Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States

With improvements in MRI technology, more informative diffusion acquisitions can be obtained to improve tissue microstructure analysis. In this study, a Multi-shell Acquisition with Increased b-Shells and Sparse ORientations (MAISSOR) is proposed to optimize diffusion acquisition. The scheme improves diffusion signal decay fitting while simultaneously improving fiber orientation distribution1 (FOD) calculations as well as diffusivity metrics, such as those derived from diffusion tensor imaging2 (DTI).

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A rapid PROPELLER technique for high resolution diffusion weighted imaging
Zhiqiang Li1, Melvyn B Ooi2, and John P Karis1

1Department of Neuroradiology, Barrow Neurological Institute, Phoenix, AZ, United States, 2Philips Healthcare, Gainesville, FL, United States

Diffusion weighted imaging is routinely used in the clinical settings. EPI is commonly used but suffers from severe geometric distortion. TSE/PROPELLER based DWI techniques are free of geometric distortion, but lead to long scan time and high SAR. In this project we propose a new SPLICE X-PROP technique to provide rapid high resolution DWI, by incorporating a SPLICE acquisition approach and a cross-blade GRASE readout into the PROPELLER technique. The improvement over conventional SPLICE PROPELLER technique is demonstrated with volunteer scans.

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Investigating microscopic diffusion anisotropy in the human kidney using multidimensional diffusion encoding
Fabio Nery1, Filip Szczepankiewicz2,3, João P. de Almeida Martins4,5, Matt G Hall1, Isky Gordon1, David L Thomas6,7, and Chris A Clark1

1Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom, 2Radiology, Brigham and Women’s Hospital, Boston, MA, United States, 3Harvard Medical School, Boston, MA, United States, 4Physical Chemistry, Lund University, Lund, Sweden, 5Random Walk Imaging AB, Lund, Sweden, 6Leonard Wolfson Experimental Neurology Centre, UCL Institute of Neurology, Queen Square, London, United Kingdom, 7Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London, United Kingdom

Diffusion tensor imaging (DTI) has been widely used to provide tissue microstructure measures such as fractional anisotropy (FA). Advances in diffusion acquisition methods (e.g. efficient spherical tensor encoding) have enabled more specific microstructural parameters to be derived, including microscopic fractional anisotropy (µFA). This work focused on extending our initial observation of µFA in the kidney through a detailed analysis of the linear and spherical diffusion encoding in healthy subjects, by comparing conventional FA to the µFA in human kidneys, and investigating the technical limitations of the current approach.

3525
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Diffusion weighted multi-spin echo sequence fuses T2-relaxometry and diffusometry
Jelle Veraart1,2, Ying-Chia Lin1,2, Tiejun E. Zhao3, and Steven H. Baete1,2

1Center for Advanced Imaging Innovation and Research (CAI2R), NYU School of Medicine, New York, NY, United States, 2Center for Biomedical Imaging, Dept of Radiology, NYU School of Medicine, New York, NY, United States, 3Siemens Medical Solutions, New York, NY, United States

Combination of diffusion weighted MRI with orthogonal measures such as T$$$_2$$$-weighting has been proposed to overcome the fit degeneracy found in microstructure modeling of diffusion signals. However, the repetition of diffusion measurements at different TE leads to unacceptably long acquisition times, hindering clinical applicability of this approach. Here, we propose an accelerated acquisition using a multi spin echo diffusion and T$$$_2$$$-weighted sequence which samples each diffusion weighting at several TEs with a CPMG read-out train after the standard monopolar diffusion encoding spin echo. In the current configuration this speeds the acquisition up by a factor of 2.5x.

3526
Computer 18
Sensitivity of 2D-Selective RF Excitations for Inner-Field-of-View Diffusion-Weighted Imaging to Field Inhomogeneities
Caspar Florin1 and Jürgen Finsterbusch1

1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Inner-field-of-view techniques based on 2D-selective RF (2DRF) excitations reduce geometric distortions of echo-planar imaging and improve diffusion-weighted imaging of the human spinal cord. A comparison of two common approaches revealed that a setup with the 2DRF excitation collinear to the image plane suffers from a reduced signal-to-noise ratio (SNR) for tall slice stacks. In this study, it is shown that the SNR loss is related to the larger sensitivity of the corresponding 2DRF excitation to frequency offsets caused by field inhomogeneities and is particularly pronounced for the large fields-of-excitation and 2DRF pulse durations needed for tall slice stacks.

3527
Computer 19
A comparative study of single shot EPI, reduced field of view EPI, PROPELLER FSE based diffusion weighted imaging in the evaluation of normal thyroid gland
Jingjing Bai1, Xiaocheng Wei2, Xijun Jiao1, Yinxia Guo1, Yanan Li1, Miaomiao Wang1, Jianxin Guo1, and Jian Yang1

1The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China, 2GE Healthcare China, Beijing, China

Thyroid gland diffusion images often suffer from high level of image distortion due to poor magnetic filed homogeneity. We evaluated the image quality and compared apparent diffusion coefficient (ADC) of healthy thyroid gland using EPI DWI, rFOV DWI and PROPELLER DWI images respectively. Our results indicated that the image quality of rFOV is better than that of EPI and PROPELLER DWI, while the image quality has no significant difference between EPI and PROPELLER DWI. Moreover, there was no significant difference in ADC value between EPI and rFOV DWI images, while the ADC value of PROPELLER EPI was significantly higher.

3528
Computer 20
Diffusion-Weighted Imaging Of Upper Abdomen: A Comparative Study In Healthy Volunteers
Zhuo Shi1, Lizhi Xie2, XinMing Zhao1, and Han Ou-Yang1

1Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, 2GE Healthcare, China, Beijing, China

Nowadays,no standard scanning protocol or parameter for upper abdomen DWI is available. Due to tension, fear or poor tolerance, patients’ respiration may vary during the scan, leading to incorrect ADC measurement and missed diagnosis. In our study, we performed quantitative and qualitative analyses of images acquired via respiratory-triggered, breath-hold and free-breathing DWI at both 1.5T and 3T, to compare their image quality and the apparent diffusion coefficient (ADC) values of upper abdomen, then decide which is the best technique for upper abdomen DWI.

3529
Computer 21
VASE-RESOLVE: Accelerated Readout Segmented Echo Planar Imaging with Compressed Sensing and Variable-Width Readout Segments
Patrick Liebig1,2,3, Robin Martin Heidemann2, Bernhard Hensel1, and David Andrew Porter3

1University of Erlangen-Nuremberg, Erlangen, Germany, 2Siemens Healthcare GmbH, Erlangen, Germany, 3University of Glasgow, Glasgow, United Kingdom

Readout-segmented echo-planar imaging (EPI) with 2D navigator correction, also known as RESOLVE, is an established method for performing high-resolution diffusion weighted imaging in clinical studies. However, the method requires long acquisition times compared to single-shot EPI. A reduction in acquisition time could be achieved with Compressed Sensing (CS), but sub-sampling of EPI-based sequences is problematic because of the phase evolution during the echo train. This work introduces a new CS sampling scheme for readout-segmented EPI that varies the readout-segment width as a function of sampling density and preserves the phase relationship between data points.

3530
Computer 22
Golden-Angle Rotating Single-Shot Acquisition (GA-RoSA) for Simultaneous High-Resolution DTI and IVIM
Qiuting Wen1, Feng Li2, Kun Zhou3, Christianne Leidecker4, and Yu-Chien Wu1

1Indiana University, School of Medicine, Indianapolis, IN, United States, 2Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, United States, 3Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 4Siemens Medical Solutions, Inc., Chicago, IL, United States

High-resolution DWI often relies on multi-shot acquisitions, which suffer from long acquisition time and motion-related phase variations. Although effort has been made to accelerate DWI acquisitions, acquiring b=0 images still requires multiple shots and multiple averages. In this work, in addition to accelerating DWI acquisitions, the proposed method (GA-RoSA) further rearranged the b=0 acquisitions to cover a range of lower b-values without increasing scan times, so that IVIM parameters can be obtained for free. With a golden-angle rotation scheme, GA-RoSA introduced sampling incoherence facilitating its combination with sparsity-based reconstruction approaches. We demonstrated its feasibility for simultaneous high-resolution DTI and IVIM.

3531
Computer 23
Can unprecedented echo times in human diffusion weighted fMRI help reveal its biological underpinnings?
Suryanarayana Umesh Rudrapatna1, Lars Mueller1, Marcello Venzi2, Richard G Wise1, and Derek K Jones1

1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom, 2School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom

The brain versus vein dilemma in BOLD fMRI has spurred research towards more direct correlates of neuronal activation. Diffusion-weighted fMRI (dfMRI) emerged as a potential alternative 17 years ago. However, its signal origins and utility have been greatly debated. In this work, we combine ultra-high-gradients and spiral readout to characterize dfMRI contrast in humans in parameter spaces (TE, b-value, SNR and resolution) that have never been accessible before. Varying TE over a wide range while keeping the b-value fixed allowed us to detect significant hemodynamic contributions to dfMRI contrast at a b-value of 1200 s/mm2.

3532
Computer 24
Novel HARDI-ZOOMit protocol detects changes in spinal cord microstructure in patients with asymptomatic non-myelopathic degenerative cervical spinal cord compression
René Labounek1,2,3, Jan Valošek1,4, Tomáš Horák5,6, Alena Svátková5,7, Petr Bednařík5,8, Pavel Hok1,2, Petr Kudlička5, Magda Horáková5,6, Jan Kočica5,6, Christophe Lenglet9, Julien Cohen-Adad10, Igor Nestrašil3,9, Josef Bednařík5,6, and Petr Hluštík1,2

1Department of Neurology, Palacký University, Olomouc, Czech Republic, 2Department of Neurology, University Hospital Olomouc, Olomouc, Czech Republic, 3Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States, 4Department of Biomedical Engineering, University Hospital Olomouc, Olomouc, Czech Republic, 5Central European Institute of Technology, Masaryk University, Brno, Czech Republic, 6Department of Neurology, University Hospital Brno, Brno, Czech Republic, 7Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Vienna, Austria, 8High Field MR Centre, Medical University of Vienna, Vienna, Austria, 9Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 10Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada

Detection of degenerative cervical spinal cord compression (DCSCC) at early stage that causes spinal cord (SC) microstructure disruption is limited when current imaging techniques are used. Early detection of damage to SC can predict symptomatic degenerative cervical myelopathy (DCM). We are presenting novel HARDI-ZOOMit protocol (High Angular Resolution Diffusion Imaging + syngo ZOOMit sequence), which is able to detect changes in microstructural diffusion MRI (dMRI) parameters (e.g. fractional anisotropy – FA, mean diffusivity – MD) in asymptomatic DCSCC. Results obtained with HARDI-ZOOMit protocol reveal higher sensitivity when compared to clinical RESOLVE (REadout Segmentation Of Long Variable Echo trains) protocol.

3533
Computer 25
Clinical feasibility of multi-band diffusion tensor imaging (DTI) using simultaneous multi-slice acquisition for presurgical planning: Comparisons with standard DTI in patients with brain tumor
Mehrnaz Jenabi1, Madeleine Gene2, Nicholas s Cho1, Ricardo Otazo3, Robert Young1, Andrei I Holodny1, and Kyung Peck3

1Radiology, MSKCC, New York, NY, United States, 2MSKCC, New York, NY, United States, 3Medical physics, MSKCC, New York, NY, United States

Standard diffusion tensor imaging (s-DTI) is currently utilized during presurgical planning to visualize white matter tracts despite its long scanning time. Multi-band DTI (mb-DTI) utilizes simultaneous multi-slice excitation, which greatly reduces scanning time and increases coverage. In this study, 42 patients with brain tumor were analyzed using mb-DTI and s-DTI in the arcuate fasciculus and corticospinal tract, two critical white matter tracts for language and motor function, respectively. When using mb-DTI, scanning time was reduced by 40% and the image quality and quantitative parameters were preserved. This study demonstrated the clinical feasibility and potential advantages of mb-DTI during presurgical planning


Microstructural Modelling & Mapping

Exhibition Hall
Wednesday 9:15 - 10:15
 Diffusion

3534
Computer 26
Comparison and Assessment of IVIM-MRI Methods Using a Capillary Flow Phantom
Moritz Jörg Schneider1,2, Thomas Gaass1,2, Julien Dinkel1,2, Jens Ricke1, and Olaf Dietrich1

1Department of Radiology, LMU University of Munich, Munich, Germany, 2Comprehensive Pneumology Center, German Center for Lung Research, Munich, Germany

In this study different intravoxel incoherent motion (IVIM) MRI methods were assessed and compared using phantom measurement. The phantom was constructed to mimic a capillary bed and allowed for the controlled application of fluid flow at varying rates. Advanced IVIM MRI methods beyond the biexponential pseudo-diffusion model were shown to be capable of accurately characterizing fluid flow inside a capillary network yielding intuitive parameters in a reproducible manner.

3535
Computer 27
What are the consequences of ignoring non-Gaussian diffusion in models of convection-enhanced drug delivery to the human brain?
Eirini Messaritaki1, S Umesh Rudrapatna2, Najmus S Iqbal1, Hannah Furby1,2,3, Emma Yhnell1, Claudia Metzler-Baddeley2, William P Gray1, and Derek K Jones2,4

1Medicine, Cardiff University, Cardiff, United Kingdom, 2Psychology, Cardiff University, Cardiff, United Kingdom, 3Huntington's Disease Centre, UCL, London, United Kingdom, 4Psychology, Australian Catholic University, Melbourne, Australia

Convection-enhanced drug delivery to the human brain is a promising method for treating neurodegenerative diseases and brain tumors. Accurate predictions of the drug concentration via computational fluid dynamics models are essential, and models not accounting for diffusion non-Gaussianity give predictions that are not in good enough agreement with experimental results. We use a fluid dynamics model recently presented in the literature, which accounts for diffusion non-Gaussianity, to calculate the differences with models that do not account for it, in data from pre-symptomatic Huntington’s disease patients and metastatic brain tumor patients. We make recommendations on the use of fluid dynamics models in the clinical setting.

3536
Computer 28
MEDUSA: a GPU-based tool to create realistic phantoms of the brain white matter microstructure using tiny spheres.
Kévin GINSBURGER1, Felix MATUSCHKE2, Fabrice POUPON3, Jean-François MANGIN3, Markus AXER2, and Cyril POUPON1

1UNIRS, CEA/Joliot/Neurospin, GIf-sur-Yvette, France, 2Research Centre Jülich, Institute of Neuroscience and Medicine, Jülich, Germany, Juelich, Germany, 3UNATI, CEA/Joliot/Neurospin, GIf-sur-Yvette, France

This work proposes a novel Microstructure Environment Designer with Unified Sphere Atoms (MEDUSA) to construct realistic white matter cellular phantoms ensuring the absence of overlapping cells. It relies on a CUDA-based collision solver that enables to reach high values of packing density and angular dispersion, even in the case of multiple fiber populations. MEDUSA thus achieves the fast construction of biomimicking white matter phantoms with fully controlled geometrical properties, including axons, astrocytes and oligodendrocytes.

3537
Computer 29
Axon diameter estimation in fixed human optic chiasm using diffusion weighted MR microscopy and microstructure-informed tractography
Mohammad Ashtarayeh1, Tobias Streubel1,2, Joao Periquito3, Andreas Pohlmann3, Thoralf Niendorf3, Evgeniya Kirilina2,4, Markus Morawski5, Carsten Jäger2, Stefan Geyer2, Muhamed Barakovic6, Alessandro Daducci7, and Siawoosh Mohammadi1

1Department of Systems Neurosciences, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 3Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 4Neurocomputation and Neuroimaging Unit, Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany, 5Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany, 6Signal Processing Lab (LTS5), Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, 7Department of computer science, University of Verona, Verona, Italy

We estimated mean axon diameter of ipsilateral bundles in a fixed human optic chiasm sample using diffusion weighted MR microscopy and COMMIT framework.  We computed that the resolution limit for axon diameters of our dMRI data is about 1.3 µm, indicating that our approach is sensitive to a larger range of axon diameter distribution (ADD) than in-vivo dMRI studies. We found a similar pattern in the estimated ADD using MRI as was reported by a histological analysis of macaque monkeys’ optic chiasm, indicating that the estimated ADD provides similar sensitivity to regional differences in microstructure properties as in ex-vivo histology.

3538
Computer 30
An observational study on the diffusion time and field strength dependency of the diffusion coefficient in human white matter
Sebastian Endt1,2, Jan Martin1, Lipeng Ning2, Lars Müller3,4, Andreas Wetscherek3,5, Michael Uder1, Bernhard Hensel6, Yogesh Rathi2, and Frederik B Laun1

1Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 2Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 3Department Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom, 5Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom, 6Center for Medical Physics and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany

Signal dependence on diffusion time has been reported in various tissues and has been connected to cellular restrictions. It is conceivable, however, that it partly originates from relaxation weightings of different compartments. In this study, we investigate the diffusion time dependence of the diffusion tensor in brain tissue at 1.5 T, 3 T and 7 T using a stimulated echo sequence. The results show clear time dependencies of axial and radial diffusivity. 7 T data show a reduction of both diffusivities, indicating a non-negligible role of compartmental relaxation weighting effects.

3539
Computer 31
A microstructure fingerprinting approach with heterogeneous axon diameters: validation on feline spinal cord
Gaëtan Rensonnet1,2, David Romascano2, Benoit Scherrer3, Simon K Warfield3, Benoit Macq1, Jean-Philippe Thiran2,4, and Maxime Taquet3

1ICTEAM, Université catholique de Louvain, Louvain-la-Neuve, Belgium, 2Signal Processing Lab (LTS5), Ecole polytechnique fédérale de Lausanne, Lausanne, Switzerland, 3Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States, 4Centre hospitalier universitaire vaudois (CHUV), University of Lausanne (UNIL), Lausanne, Switzerland

A microstructure fingerprinting approach is proposed in which an optimal single-fascicle configuration is selected from a pre-computed collection of Monte Carlo diffusion signals, or fingerprints, uniquely relating the diffusion MRI signals to the underlying axon properties. The simulated 3D geometries feature randomly-placed cylinders with diameter heterogeneity. The approach is validated on a public dataset of ex vivo cat spinal cord and exhibits indices of axon density and of the mean and standard deviation of the axon diameter distribution in agreement with histological measurements. The method is shown to outperform AMICO, which relies on approximate analytical expressions for the signal, and a simpler model using Monte Carlo simulations in a homogeneous packing of identical cylinders.

3540
Computer 32
A Diffusion MRI Approach to Tumour Microstructure Modeling with Two Cell Populations of Different Sizes
Shu Xing1 and Ives R. Levesque1,2

1Medical Physics Unit and Department of Physics, McGill University, Montreal, QC, Canada, 2Research Institute of McGill University Health Center, Montreal, QC, Canada

Advanced diffusion-weighted MRI allows the characterization of cancer tumours noninvasively by estimating cell radius R and volume fraction vin. Existing methods map the apparent R and vin , under the assumption that a given voxel contains one cell population. This work investigates the feasibility of estimating the radii and volume fractions of 2 cell populations co-existing in the same voxel. This method could be useful in studying biphasic tumours like round cell/myxoid liposarcoma, which consist of high-grade and low-grade tumour cells, where the percentage of high-grade cells is strongly related to the risk of metastasis and changes the course of treatment. 

3541
Computer 33
HOTmix: characterizing hindered diffusion using a mixture of generalized higher order tensors
David Romascano1,2, Erick J. Canales-Rodriguez3, Jonathan Rafael-Patino1, Marco Pizzolato1, Gaëtan Rensonnet1,4, Muhamed Barakovic1, Gabriel Girard1,5, Alessandro Daducci6, Tim B. Dyrby2,7, and Jean-Philippe Thiran1,5

1Signal Processing Lab (LTS5), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Danish Research Center for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 3Department of Radiology, University Hospital Center, Lausanne, Switzerland, 4ICTEAM, Université catholique de Louvain, Louvain-la-Neuve, Belgium, 5Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland, 6Department of Computer Science, University of Verona, Verona, Italy, 7Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark

We present HOTmix, a new model to describe the diffusion MRI signal for molecules undergoing hindered diffusion. HOTmix is based on a mixture of generalized higher order tensors, explicitly incorporating the diffusion sequence’s time-dependent parameters. The method was evaluated on simulated diffusion MRI signals obtained through Monte Carlo simulations, using intermediate diffusion times, mimicking both ex-vivo and in-vivo conditions. HOTmix provided better reconstructions compared to the standard diffusion tensor, the kurtosis tensor, and a single generalized higher order tensor. In future work, we will explore whether modelling the hindered compartment using HOTmix improves microstructural features estimated using dMRI.

3542
Computer 34
Double diffusion encoding enables unique parameter estimation of the Standard Model in diffusion MRI
Santiago Coelho1,2, Jose M. Pozo1,2, Sune N. Jespersen3,4, Derek K. Jones5,6, and Alejandro F. Frangi1,2

1Centre for Computational Imaging & Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, United Kingdom, 2Leeds Institute for Cardiac and Metabolic Medicine (LICAMM), School of Medicine, University of Leeds, Leeds, United Kingdom, 3Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, 4Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark, 5Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom, 6School of Psychology, Australian Catholic University, Melbourne, Australia

The widely adopted Standard Model (SM) for diffusion in white matter tissue has been shown to possess intrinsic degeneracies, making parameter estimation from single diffusion encoding (SDE) data ill-conditioned. We extend the SM to a multidimensional diffusion MRI acquisition and analyse the case where the fibre orientation distribution function (fODF) is a Watson distribution. The information contained in the kurtosis tensor, accessed by SDE, is insufficient to recover biophysical model parameters from the MR signal. We prove that Double Diffusion Encoding (DDE), letting us additionally access the full diffusion tensor covariance, makes parameter estimation well-posed.

3543
Computer 35
Estimation of Axon Conduction Delay, Conduction Speed, and Diameter from Information Flow using Diffusion MRI and MEG
Samuel Deslauriers-Gauthier1 and Rachid Deriche1

1Athena Project-Team, Inria, Université Côte d'Azur, Sophia Antipolis - Méditerranée, France

Information transmission delays in the brain are generated by the physical properties of axons, including their length and diameter. These delays have a range of a few milliseconds and can thus be observed in bioelectric recordings such as electroencephalography and magnetoencephalography (MEG). In this work, we present a novel algorithm to estimate axon diameters from diffusion MRI and MEG. This approach identifies information flow between cortical regions using a model where transmission delays are parameters. The delays which maximize information transfer are identified and, using streamline length obtained through tractography, are then converted to axon diameters. We present results obtained on four subjects of the Human Connectome Project.

3544
Computer 36
What perivascular spaces do to diffusion MRI?
Shi Jia Teo1,2,3, Valerij G. Kiselev1, Bibek Dhital1, and Marco Reisert4

1Medical Physics, University Medical Centre Freiburg, Freiburg, Germany, 2Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany, 3Faculty of Biology, University of Freiburg, Freiburg, Germany, 4University Medical Centre Freiburg, Freiburg, Germany

PVS is gaining importance in a many research fields. In using both in vivo and formalin fixed ex vivo methods, we sought to better understand what parameters in dMRI may be used to understood be as PVS in brain tissue.

3545
Computer 37
Surface-to-Volume ratio mapping using Oscillating Gradient Diffusion (OGSE) Spectroscopy for cancer characterization in the ex-vivo prostate
Jeevan Shah1, Roger Bourne2, Geoffrey Watson3, and Andre Bongers1

1The University of New South Wales, Sydney, Australia, 2The University of Sydney, Sydney, Australia, 3Royal Prince Alfred Hospital, Sydney, Australia

This study investigates mapping of Surface-to-Volume (S/V) ratios from short diffusion time derived ADC maps to detect and characterize prostate cancer. ADC was mapped using a cos-OGSE DWI (fosc=50-200Hz) in one unfixed prostate (Gleason 4+4). Using a previously established model, S/V and free cytosol diffusivity (D0) maps were estimated by fitting the temporal behaviour of ADC. S/V and D0 were able to clearly and significantly separate the cancer and normal peripheral zone as indicated by a t-test and ROC curves. The geometrical nature of S/V may provide additional information to better characterize prostate cancer independent from diffusion related parameters. 

3546
Computer 38
Diffusion Time Dependence in Crossing Fiber Area in in vivo Human White Matter
Masaaki Hori1, Tomoko Maekawa1,2, Kouhei Kamiya2, Yasuhiko Tachibana3, Koji Kamagata1, Issei Fukunaga1, Katsutoshi Murata4, Thorsten Feiweier5, Akifumi Hagiwara1,2, Shohei Fujita1,2, Ryusuke Irie1,2, Christina Andica1, Kanako Kunishima Kumamaru1, Akihiko Wada1, and Shigeki Aoki1

1Radiology, Juntendo University School of Medicine, Tokyo, Japan, 2Radiology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan, 3Radiology, National Institute of Radiological Sciences, Chiba, Japan, 4Siemens Japan K.K, Tokyo, Japan, 5Siemens Healthcare GmbH, Erlangen, Germany

We investigated the diffusion time dependency of diffusion metrics in the white matter crossing fiber areas with different diffusion times using OGSE, PGSE and STEAM-DTI in in vivo human white matter at 3T. Our results show that ADC and AD decreased with increasing diffusion time at Δless than 100ms; after that ADC increased with increasing diffusion time. RD decreased and FA increased with increasing diffusion time. Moreover, the changes of white matter fODF in the white matter crossing fiber area at different diffusion times are shown.

3547
Computer 39
Random walk simulation of diffusion MRI in geometries constructed from two-photon microscopy of cortical gray matter
Nima Gilani1, Sven Hildebrand1, Anna Schueth1, and Alard Roebroeck1

1Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands

The purpose of this study was to more quantitatively characterize the cytoarchitecture of cortical tissue from microscopy in order to simulate diffusion signal in the cortex and to better understand its changes with density, size and permeability of cell bodies, axons and dendrites. Two random walk simulation methods are presented which show effects of cortical laminar microstructure on ADC and K. This could open possibilities of detecting cortical cytoarchitecture, i.e. cell body sizes and densities, and their pathologies with diffusion MRI. 

3548
Computer 40
Probing tissue microstructure using filtered q-trajectory imaging
Lipeng Ning1,2, Filip Szczepankiewicz1,2, Markus Nilsson3, Yogesh Rathi1,2, and Carl-Fredrik Westin1,2

1Harvard Medical School, Boston, MA, United States, 2Brigham and Women's Hospital, Boston, MA, United States, 3Lund University, Lund, Sweden

We introduce an approach to characterize tissue microstructure using an extension of the q-trajectory imaging (QTI) technique in diffusion MRI. Our approach applies multiplicative filters to the diffusion tensor distribution (DTD) functions of the underlying tissue to obtain more specific information of tissue microstructure using the statistical moments of the filtered DTD's.We propose several descriptive statistics to distinguish microstructures that cannot be separated using existing methods.These measures are demonstrated in simulations and in vivo data acquired from a human brain.

3549
Computer 41
Time Dependence in B-Tensor Encoding
Noemi G. Gyori1,2, Kiran K. Seunarine2, Matt G. Hall2, Christopher A. Clark2, Daniel C. Alexander1, and Enrico Kaden1

1Centre for Medical Image Computing, University College London, London, United Kingdom, 2Great Ormond Street Institute of Child Health, University College London, London, United Kingdom

B-tensor encoding is becoming increasingly popular in microstructural imaging. In this technique microscopic tissue features are estimated by using different gradient waveforms that typically have different time regimes. This work studies for the first time two potential time-dependence issues that arise from these methods in-vivo in the human brain. We detect time-dependence effects in both cases, and even though these are small on a clinical system, they should not be overlooked.

3550
Computer 42
Comparing Fiber Orientation Estimates from CLARITY and Diffusion MRI in Macaque Visual Cortex
Muhamed Barakovic1,2, Christoph Leuze2, Ailey K. Crow3, Qiyuan Tian2,4, Alessandro Daducci5, Jean-Philippe Thiran1,6, Karl Deisseroth3,7,8,9, and Jennifer A. McNab2

1Signal Processing Lab (LTS5), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Department of Radiology, Stanford University, Stanford, CA, United States, 3CNC Program, Stanford University, Stanford, CA, United States, 4Department of Electrical Engineering, Stanford University, Stanford, CA, United States, 5Department of Computer Science, University of Verona, Verona, Italy, 6Radiology Department, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland, 7Department of Bioengineering, Stanford University, Stanford, CA, United States, 8Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States, 9Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States

Tissue clearing techniques offer new possibilities for reconstructing precise 3D axons trajectories. Here, we cleared a 1.5cmx1.3cmx0.3cm cuboid of rhesus macaque visual cortex using CLARITY 3D histology with a neurofilament stain to highlight axonal projections and compared the CLARITY-based fiber orientation estimate to a diffusion tensor MRI atlas. We found better agreement in grey matter than  in white matter, potentially reflecting difficulties estimating the structure tensor in highly saturated regions of the CLARITY sample. This work demonstrates one of the largest and highest quality CLARITY cuboids from a macaque brain and explores key steps in the co-registration and analysis required to make a robust comparison against DTI data.

3551
Computer 43
Microstructural  Parameter Estimation of Skeletal Muscle Using Random Forest Model of dMRI
Noel M. Naughton1, Nicolas R. Gallo2, Aaron T. Anderson3,4, and John J. Georgiadis1,2

1Mechanical Science and Engineering, University of Illinois at Urbana Champaign, Urbana, IL, United States, 2Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, 3Beckman Institute for Advanced Science and Technology, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 4Radiology, Carle Foundation Hospital, Urbana, IL, United States

Results are presented for a random forest model to estimate skeletal muscle microstructure parameters from dMRI data. The model exhibits the ability to estimate microstructural parameters from both numerically simulated and experimentally acquired dMRI data suggesting that random forests, and machine learning more generally, may be a useful tool in dMRI microstructure estimation of skeletal muscle. 

3552
Computer 44
Reliability of microstructural quantification with diffusion MRI in brain tumors.
Umberto Villani1,2, Erica Silvestri1,2, Marco Castellaro1,2, Maurizio Corbetta1,3, and Alessandra Bertoldo1,2

1Padova Neuroscience Center, University of Padova, Padova, Italy, 2Department of Information Engineering, University of Padova, Padova, Italy, 3Department of Neuroscience, University of Padova, Padova, Italy

Most existing biophysical models used to quantify diffusion microstructural information are designed for the healthy brain. When pathological processes occur, the diffusion signal of cancerous regions is altered, possibly biasing the fitting results of these models and making their parameter estimates unreliable. In this work, we investigate the precision and accuracy of estimates provided by several well known diffusion models, by evaluating their goodness-of-fit with residual sum of squares map and the parameter reliability with the bootstrap technique.

3553
Computer 45
Diffusion Kurtosis Imaging (DKI) Biomarkers correlate with dysfunction in the EAE model of MS
Andrey Chuhutin1, Brian Hansen1, Agnieszka Wlodarczyk2, Trevor Owens2, Noam Shemesh3, and Sune Nørhøj Jespersen1,4

1CFIN, Aarhus University, Aarhus, Denmark, 2Department of Neurobiology Research, Institute for Molecular Medicine,University of South Denmark, Odense, Denmark, 3Champalimaud Center for Unknown, Lisbon, Portugal, 4Dept. of Physics and Astronomy, Aarhus University, Aarhus, Denmark

To study the relationship between microstructure and disability, 18 ex-vivo spinal cords from a mouse model of MS (EAE) were investigated using DKI and a biophysical model of diffusion. Diffusion data were acquired together with T2* images to delineate lesions. Kurtosis tensors and microstructural parameters were used for statistical analysis using a LME model. The results show a strong relation between disability and kurtosis tensor parameters similar to observations in other hypomyelinating MS models and in patients. Conversely, changes in model parameters, such as extra-axonal axial diffusivity, are clearly different from previous studies using other animal models of MS.

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Effects of T2 relaxations on diffusion heterogeneity in the presence of tumor malignancy-related microstructural changes
Chu-Yu Lee1, In-Young Choi1,2,3, and Phil Lee1,3

1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, United States, 2Department of Neurology, University of Kansas Medical Center, Kansas City, KS, United States, 3Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States

Cell compartments can present non-uniform T2 relaxations, depending on tissue properties. The non-uniform T2 relaxation has been shown to affect measurements of apparent diffusion coefficients (ADC). In additional to ADC, diffusion heterogeneity measured by modeling non-monoexponential decay has been used to characterize water diffusion in tissue microstructure. The purpose of this study is to study the effects of non-uniform T2 relaxations on the diffusion heterogeneity using a Monte Carlo simulation. The results demonstrate that the diffusion heterogeneity may provide more information about water diffusion  within microstructure with non-uniform T2 relaxations. 

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Delineation of white matter microstructural maturation of infant brain with DKI
Chenying Zhao1,2, Minhui Ouyang2, Michelle A Slinger2, and Hao Huang2,3

1Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Radiology, Children’s Hospital of Philadelphia, Philadelphia, PA, United States, 3Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States

Diffusion kurtosis imaging (DKI) based on multi-shell diffusion MRI may offer extra information on WM microstructural complexity changes during infant development compared to conventional DTI. After acquiring DKI and DTI from 18 normal infants aged 0-1 year, we measured the mean kurtosis (MK) and fractional anisotropy (FA) of all major WM tracts by combining WM skeletonization process and WM tract labels. Significant age-related increases in both MK and FA were found in all tracts. Distinctive developmental trajectories of WM tracts with MK measurements compared to those with FA measurements were revealed, indicating heterogeneous increases of microstructural complexity among WM tracts.

3556
Computer 48
Time dependence and stability of diffusion tensor metrics in a hydrophilic, electrospun, water-perfused, hollow fiber phantom at 3T
Amy McDowell1, Matt G Hall1,2, Fenglei Zhou3, Thorsten Feiweier4, Geoff JM Parker3, and Chris A Clark1

1Developmental Imaging and Biophysics, University College London, London, United Kingdom, 2Medical Radiation Physics, National Physical Laboratory, London, United Kingdom, 3University of Manchester, Manchester, United Kingdom, 4Neurology Applications Development, Siemens Healthcare GmbH, Erlangen, Germany

We assess the dependence of Diffusion Tensor Imaging metrics on diffusion time using a well-characterised hydrophilic phantom comprised of parallel hollow fibers with radii comparable to axons in healthy human white matter.

3557
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Experimental validation and SNR analysis of a clinical double diffusion encoding sequence
Leevi Kerkelä1, Rafael Neto Henriques2, Matt Hall1, Chris Clark1, and Noam Shemesh2

1UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 2Champalimaud Neuroscience Programme, Lisbon, Portugal

Double diffusion encoding (DDE) allows the estimation of microscopic fractional anisotropy (μFA), which is a promising metric for studying microstructural properties of brain tissue independent of orientation dispersion. However, a large number of acquisitions is needed to obtain a rotationally invariant measurement of μFA, which poses a problem in clinical settings. A DDE protocol with a reduced number of acquisitions has recently been proposed as a solution. In this study, we assessed the accuracy of this approach and its potential for reporting μFA accurately. Our results show that a reduced number of acquisitions is sufficient for characterizing μFA.

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Precision of microscopic fractional anisotropy estimation using double diffusion encoding
Leevi Kerkelä1, Rafael Neto Henriques2, Matt Hall1, Noam Shemesh2, and Chris Clark1

1UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, 2Champalimaud Neuroscience Programme, Lisbon, Portugal

Microscopic fractional anisotropy (μFA) estimation using diffusion MRI is a promising new method for quantifying microstructure, diagnosing pathologies, and measuring brain  development. In order for μFA to be a useful metric in clinical and neuroscientific research, its robustness to noise has to be properly understood. In this study, precision of μFA estimation was quantified for different noise levels using propagation of error calculations, simulations, and imaging experiments. We show that μFA is non-linearly sensitive to noise, being the most instable at low values of mean diffusivity (MD) and μFA, and that increasing accuracy by correcting for higher order effects results in decreased precision.



Microstructure Modeling: 1

Exhibition Hall
Wednesday 9:15 - 10:15
 Diffusion

3559
Computer 51
Machine learning based estimation of axonal properties in the presence of beading
Kévin GINSBURGER1, Felix MATUSCHKE2, Fabrice POUPON3, Jean-François MANGIN3, Markus AXER2, and Cyril POUPON1

1UNIRS, CEA/Joliot/Neurospin, GIf-sur-Yvette, France, 2Research Centre Jülich, Institute of Neuroscience and Medicine, Jülich, Germany, Juelich, Germany, 3UNATI, CEA/Joliot/Neurospin, GIf-sur-Yvette, France

In this work, we investigate the potential of machine learning techniques to make one step forward by quantitatively estimating beading amplitude, a specific marker of pathological beading using frequency-dependent changes in diffusion measurements. Classification and regression are performed using Extremely Randomized Trees from OGSE signals corresponding to 6 distinct frequencies and synthesized from numerical simulations in realistic white matter phantoms depicting beaded axons.

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Tensorial formulation allowing to verify or falsify the microstructural standard model from multidimensional diffusion MRI
Jose M. Pozo1,2, Santiago Coelho1,2, and Alejandro F. Frangi1,2

1Centre for Computational Imaging & Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, United Kingdom, 2Leeds Institute for Cardiac and Metabolic Medicine (LICAMM), School of Medicine, University of Leeds, Leeds, United Kingdom

The standard model (SM) has been proposed as an appropriate diffusion MRI microstructural model for brain white matter. Using the cumulant expansion up to 2nd order in the b-tensor, it has been recently shown that multidimensional diffusion encoding makes the model parameter estimation problem well-posed. However, the tensorial properties of the expansion and their relationship with the SM assumptions have not been exploited. We reformulate the solution of the SM in an elegant tensorial form and analyse the constraints the SM imposes, showing how they can potentially falsify the model. Some simulations show the test feasibility for high-quality signals ($$$\text{SNR}\geq 50$$$).

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Permeable Barrier Modeling of Age Induced Changes in the Time Dependent Diffusion Eigenvalues
Vadim Malis1, Sinha Shantanu2, Edward Smitaman2, and Usha Sinha3

1Physics, UC San Diego, San Diego, CA, United States, 2Radiology, UC San Diego, San Diego, CA, United States, 3Physics, San Diego State University, San Diego, CA, United States

The time dependence of the diffusion eigenvalues derived from diffusion tensor imaging allows one to probe tissue microstructure.  A diffusion model is required to derive inferences about the microstructure from the time dependent eigenvalue data.  We applied the Random Permeable Barrier Model1 to the time dependent diffusion data to infer age related changes in skeletal muscle microarchitecture. The tertiary eigenvalue at the largest diffusion time was significantly different between young and senior cohorts.  Model derived myofiber size decreased and free diffusion coefficient increased with age, though neither parameter reached significance.

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Estimating mixtures of 6D diffusion tensor distributions with "Magic DIAMOND": are b-plates better than b-spheres?
Alexis Reymbaut1, Alex Valcourt Caron1, Guillaume Gilbert2, Simon K. Warfield3, Maxime Descoteaux1, and Benoit Scherrer3

1Université de Sherbrooke, Sherbrooke, QC, Canada, 2MR Clinical Science, Philips Healthcare Canada, Markham, ON, Canada, 3Dept. of Radiology, Boston Children’s Hospital, Boston, MA, United States

Tensor-valued diffusion encoding enables disentangling isotropic and anisotropic diffusion components. However, its impact on estimating brain microstructural features has only been studied in a handful of parametric models. In this work, we evaluate the Magic DIAMOND model, that allows characterization of crossing fascicles and assessment of diffusivities for each, using combinations of linear, planar and spherical encodings in vivo. Building statistics through stratified bootstrap, we show that spherical encoding substantially increases the variance in estimated parameters and should be avoided. Planar encoding, on the other hand, did not offer clear improvement or worsening within our current acquisition scheme and setup.

3563
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MicroLearn: Framework for machine learning, reconstruction, optimization and microstructure modeling
Shreyas Fadnavis1, Marco Reisert2, Hamza Farooq3, Maryam Afzali4, Cheng Hu5, Bago Amirbekian6, and Eleftherios Garyfallidis1

1Intelligent Systems Engineering, Indiana University Bloomington, Bloomington, IN, United States, 2University Medical Center Freiburg, Freiburg, Germany, 3The University of Minnesota Twin Cities, Minneapolis, MN, United States, 4Cardiff University, Cardiff, United Kingdom, 5Psychological and Brain Sciences, Indiana University Bloomington, Bloomington, IN, United States, 6Databricks, San Francisco, CA, United States

MicroLearn is a Machine Learning and Model Fitting framework that enables modular construction of multi-compartment microstructure models in crossings with fast and accurate parameter estimation.

3564
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Investigating the Benefits of Incorporating Higher Order Spherical Harmonics in Axon Diameter Measurements
Qiuyun Fan1,2, Aapo A Nummenmaa1,2, Qiyuan Tian1,2, Ned A Ohringer1,2, Thomas Witzel1,2, Lawrence L Wald1,2,3, Bruce R Rosen1,2,3, and Susie Y Huang1,2,3

1Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

Separating out the scalar and orientation-dependent components of the diffusion MRI signal offers the possibility of increasing sensitivity to microscopic tissue features unconfounded by the fiber orientation. Recent approaches to estimating apparent axon diameter in white matter have employed spherical averaging to avoid the confounding effects of fiber crossings and dispersion at the expense of losing sensitivity to effective compartment size. Here, we investigate the feasibility and benefits of incorporating higher-order spherical harmonic (SH) components into a rotationally invariant axon diameter estimation framework and demonstrate improved precision of axon diameter estimation in the in vivo human brain.

3565
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On the feasibility of apparent exchange rate mapping in non-periodic systems with multiple cell sizes
Dominik Ludwig1,2, Frederik Bernd Laun3, Peter Bachert1, and Tristan Anselm Kuder1

1Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Institute of Radiology, University Hospital Erlangen (FAU), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany

Apparent exchange rate (AXR) mapping might provide an insight into the exchange of water between intra- and extracellular space by using a double-diffusion encoded sequence with varying mixing times between the two gradient pairs. The connection between AXR and permeability has already been validated for simplified two-compartment models. However, multi-compartment systems and non-periodic geometries have not been evaluated so far. In this study, we were able to show that it is also possible to reliably connect permeabilities to AXR-values for these geometries. Furthermore, the AXR was only dependent on average cell size and not on the number of compartments.

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Computational frameworks for multi-fascicle models: impact on microstructural descriptors
Benjamin Schloesing1,2, Maxime Taquet3, Jean-Philippe Thiran2, Simon Keith Warfield1, and Benoit Scherrer1

1Computational Radiology Laboratory,Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States, 2Signal Processing Lab (LTS5), École polytechnique fédérale de Lausanne, Lausanne, Switzerland, 3University of Oxford, Oxford, United Kingdom

When performing operations on multi-fascicle DCI models, the need to preserve microstructural descriptors such as fFA and fMD is important. In this work we compared different multi-fascicle computational frameworks by assessing their impact on microstructure properties. Specifically, we investigated the impact after geometrical transformation and averaging of multi-fascicle models, two key operations when carrying out population studies. We found that Euclidean and log-Euclidean frameworks resulted in a decrease of fFA and fMD. More surprisingly, the values of microstructural descriptors depended on the number of subjects. The quaternion framework, in contrast, was the best at preserving microstructural features.

3567
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Non-parametric axon diameter distribution mapping with PGSE: reconstruction of uni- and multimodal distributions
David Romascano1,2, Jonathan Rafael-Patino1, Muhamed Barakovic1, Alessandro Daducci3, Jean-Philippe Thiran1,4, and Tim B. Dyrby2,5

1Signal Processing Lab (LTS5), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Danish Research Center for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 3Department of Computer Science, University of Verona, Verona, Italy, 4Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland, 5Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark

White matter diffusion MRI enables non-invasive estimation of the axon diameter distribution, which is of interest as it modulates communication speed and delays between brain regions, and changes during development and pathology. Distribution mapping is challenging: current methods simplify it by either estimating the mean diameter, imposing parametric distributions, or combining non-parametric approaches with Double Diffusion Encoding. We present a non-parametric framework based on a PGSE protocol. Simulations show robust reconstruction of unimodal and bimodal distributions. The method is sensitive to population specific changes within bimodal distributions, as long as the underlying populations are separated by a minimum distance.

3568
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Polynomial Meta-Model of Bloch-Torrey Equation for Track-based Regularization of Microstructural Inversion
Noel M. Naughton1, Arihant Jain1, and John J. Georgiadis2,3

1Mechanical Science and Engineering, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 2Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, 3Mechanical Science and Engineering, University of Illinois at Urbana Champaign, Urbana, IL, United States

A meta-model approach is presented which fits a multi-dimensional polynomial to numerical solutions of the Bloch-Torrey equation after being parameterized by microstructural and diffusion encoding parameters. This meta-model allows analytical representation of the solution space enabling analytical analysis of the space as well as reduced computational cost to solutions that do not need precise results. Possible uses of such a model are outlined, such as its use in allowing muscle tractography results to regularized by neighboring voxels in its defined muscle tract.

3569
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Improving Tractography in Baby Diffusion MRI via Asymmetric Spectrum Imaging
Ye Wu1, Weili Lin1, Dinggang Shen1, Pew-Thian Yap1, and the UNC/UMN Baby Connectome Project Consortium Consortium1

1Department of Radiology and BRIC, University of North Carolina, Chapel Hill, Chapel Hill, NC, United States

Fiber tractography in baby diffusion MRI is challenging due to the low and spatially-varying diffusion anisotropy. In this abstract, we will introduce a method called asymmetric spectrum imaging (ASI) to improve estimation of white matter pathways in the baby brain by (1) incorporating an asymmetric fiber orientation model to help resolve subvoxel fiber configurations such as fanning and bending, and (2) explicitly modeling the spectrum of diffusion typical in the developing brain.

3570
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Diffusion of the perivascular space fluid is anisotropic in conventional DWI
Farshid Sepehrband1, Ryan P Cabeen1, Jeiran Choupan1,2, Giuseppe Barisano1,3,4, Meng Law1,5, and Arthur W Toga1

1Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 2Department of Psychology, University of Southern California, Los Angeles, CA, United States, 3Neuroscience graduate program, University of Southern California, Los Angeles, CA, United States, 4Department of Radiology, University of Southern California, Los Angeles, CA, United States, 5Department of Radiology, Alfred Health, Melbourne, Australia

Perivascular space (PVS), also known as Virchow-Robin space, is a pial-lined, fluid-filled structure that surrounds vessels in the cerebral cortex 1,2, and occupies a large portion of the cerebral tissue. PVS has an anisotropic morphology 3–5 and is mainly aligned with the white matter 6. However, its diffusion MRI profile has not been studied. Here we show experimental evidences that that PVS can be measured with diffusion MRI and the signature of this compartment is anisotropic.

3571
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Dependence of harmonic power on b-value for fiber ball imaging: comparison of theory and experiment
Hunter G. Moss1,2, Emilie T. McKinnon1,2,3, Joseph A. Helpern1,2, and Jens H. Jensen1,2

1Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States, 2Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, United States, 3Department of Neurology, Medical University of South Carolina, Charleston, SC, United States

Fiber ball imaging (FBI) is a recently proposed diffusion MRI (dMRI) method for estimating fiber orientation density functions together with specific microstructural parameters in white matter. The theory underlying FBI predicts the b-value dependence for the dMRI harmonic power of any given degree as long as the b-value is sufficiently large. Good agreement between theory and experiment has been previously demonstrated for the zero-degree harmonic power. Here the predicted functional forms for higher degree harmonics are shown to also agree well with experimental measurements, providing additional support for the validity of FBI.

3572
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Diffusion time dependence in the mid-time regime: a simulation study using PGSE.
Annelinde Buikema1, Arjan den Dekker1,2, and Jan Sijbers1

1imec-Visionlab, Department of Physics, University of Antwerp, Antwerp, Belgium, 2Delft Center for Systems and Control, Delft University of Technology, Delft, Netherlands

The purpose of this work is to study the effect of varying the diffusion time on the estimation of the parameters of the two-compartment diffusion tensor model in the mid-time regime. Simulation results show that the precision of the diffusion time-dependent compartmental parameter estimates increases when a variable echo time acquisition scheme is used. At low SNR, however, including diffusion time-dependence may lead to a high bias and variance compared to the more conventional non diffusion time-dependent model.

3573
Computer 65
Biases of microstructure models in baby diffusion MRI
Khoi Minh Huynh1, Tiantian Xu2, Ye Wu2, Geng Chen2, Weili Lin2, Dinggang Shen2, Pew-Thian Yap2, and the UNC/UMN Baby Connectome Project Consortium2

1Biomedical Engineering Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 2Department of Radiology and BRIC, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

In this abstract, we show that some commonly used microstructure models do not perform as aspected when dealing with baby diffusion MRI, resulting in biased measurements. We found that this is mainly due to the greater water content in the developing brain. We show that the recently introduced Spherical Mean Spectrum Imaging (SMSI) [4] gives stable measurements in the presence of free water, making it well-suited for baby diffusion MRI.

3574
Computer 66
MicroQIT - A Computational Framework for Population Microstructure Imaging
Ryan P Cabeen1 and Arthur W Toga1

1Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, Los Angeles, CA, United States

Microstructure imaging provides a quantitative tool for characterizing neural tissue with diffusion MRI and expanding our understanding of how the brain changes in health and disease. However, robust computational tools are needed for population imaging studies, so we developed a computational framework (MicroQIT) using the Quantitative Imaging Toolkit to meet this need by providing regional summaries and spatially normalized microstructure parameter maps. It supports a variety of ways to extract microstructure information from multi-shell diffusion MRI, leverages grid computing environments, and is available for use by the research community for future studies.

3575
Computer 67
An in vivo investigation on quantitative metrics of diffusion kurtosis tensor: the effect of diffusion gradient parameters in the clinical setting
Kuan-Hung Cho1, Richard Buschbeck2, Shih-Yen Lin1,3, Ezequiel Farrher2, Ming-Jye Chen1, Chia-Wen Chiang1, N. Jon Shah2,4,5,6, Chang-Hoon Choi2, and Li-Wei Kuo1,7

1Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli County, Taiwan, 2Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany, 3Department of Computer Science, National Chiao Tung University, Hsinchu, Taiwan, 4Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Jülich, Germany, 5JARA - BRAIN - Translational Medicine, Aachen, Germany, 6Department of Neurology, RWTH Aachen University, Aachen, Germany, 7Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan

Diffusion kurtosis imaging (DKI) is an emerging technique that provides additional information to delineate tissue microstructures by quantifying the non-Gaussian water molecular diffusion. Although the capability of DKI has been demonstrated, the effects of diffusion gradient parameters on its quantitative metrics, particularly in the clinical setting, have not been fully understood yet. This study aims to investigate the effect of diffusion gradient parameters on diffusion kurtosis tensor calculation and its quantitative metrics. In vivo results show that diffusion gradient duration has incremental influence on DKI quantitative metrics in the clinical setting. Further investigation with more subjects would help to statistically solidify our findings.

3576
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Test-retest reliability of 3-tissue constrained spherical deconvolution of diffusion MRI data by analysis of three separate cohorts
Benjamin T Newman1, Thijs Dhollander2,3, Kristen A Reynier4, Matthew B Panzer4, and Thomas Jason Druzgal1

1Department of Radiology & Medical Imaging, Division of Neuroradiology, University of Virginia Health System, University of Virginia, Charlottesville, VA, United States, 2The Florey Department of Neuroscience, University of Melbourne, Melbourne, Australia, 3The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 4Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, United States

It has previously been demonstrated that, by using 3-tissue constrained spherical deconvolution, separate compartments encompassing cerebrospinal fluid-like, white matter-like, and grey matter-like, signal fractions can be derived from diffusion MRI data. This study explores the reliability of these compartments in three test-retest cohorts with a variety of timescales and scanning parameters. Whole-brain average signal fractions show excellent reliability across all datasets, particularly in determining the CSF-like signal fraction. This suggests that variations in whole brain signal fraction measurements are likely to be attributable to experimental manipulation or pathology and not variation introduced by performing the analysis. 

3577
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Powering Up Microstructural Imaging:  assessing cross-metric and cross-tract statistical power on an ultra-strong gradient MRI system
Kristin Koller1, Suryanarayana Umesh Rudapandra1, Maxime Chamberland1, Erika Raven1, Greg D Parker1, Chantal Tax1, Mark Drakesmith1, John C Evans1, Tobias C Wood2, and Derek K Jones1

1Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom, 2Department of Neuroimaging, King's College London, London, United Kingdom

We present cross-metric and cross-tract assessment of test-retest repeatability for microstructure measures on an ultra strong gradient MRI scanner (CONNECTOM 3T) in the human brain. We show that several MRI metrics of tissue microstructure are reliable and present relative sample sizes required to provide sufficient statistical power across different white matter pathways and microstructure metrics.

3578
Computer 70
Improving reproducibility of diffusion connectome analysis using deep convolutional neural network model
Min-Hee Lee1, Nolan Baird O'Hara2, and Jeong-Won Jeong3

1Pediatrics and Translational Imaging Laboratory, Wayne State University School of Medicine, Detroit, MI, United States, 2Translational Neuroscience Program, Wayne State University School of Medicine, Detroit, MI, United States, 3Pediatrics, Neurology and Translational Imaging Laboratory, Wayne State University School of Medicine, Detroit, MI, United States

Reproducibility of diffusion-weighted structural connectomes is highly dependent on acquisition and tractography model, limiting the interpretation of connectomes acquired in the clinical setting. This study proposes a novel deep convolutional neural network (DCNN) to improve the reproducibility of structural connectomes, by which highly reproducible streamlines can be identified via an end-to-end deep learning of reference streamline coordinates in Human Connectome Project diffusion data. Preliminary results demonstrate that the proposed DCNN prediction model can improve the reproducibility of clinical connectomes (31.29% of F-statistics in intraclass correlation coefficient) and effectively remove noisy streamlines based on based on their poor prediction probabilities.

3579
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Resolving crossing fibers with the inclusion of intra-axonal diffusion modeling
Chunyu Song1, Peng Sun2, Zezhong Ye3, and Sheng-Kwei (Victor) Song4

1Biomedical Engineering, Washington University in St. Louis, st louis, MO, United States, 2Radiology, Washington University School of Medicine, St. Louis, MO, United States, University City, MO, United States, 3Chemistry, Washington University in St. Louis, st louis, MO, United States, 4Radiology, Washington University School of Medicine, St. Louis, MO, United States, Saint Louis, MO, United States

A new diffusion histology imaging (DHI) model is proposed to model crossing fibers considering both intra- and extra-axonal water diffusion, along with extra-axonal isotropic diffusion within an image voxel. Both Monte-Carlo simulation and in vivo MRI data from one healthy volunteer brain were examined to assess whether DHI can resolve crossing fibers while quantifying axonal injury, demyelination, and inflammation.

3580
Computer 72
A diffusion MRI pipeline leveraging Nextflow & Singularity: Robust, Efficient, Reproducible in time!
Guillaume Theaud1, Jean-Christophe Houde1, Felix Morency2, and Maxime Descoteaux1

1Sherbrooke Connectivity Imaging Laboratory (SCIL), Université de Sherbrooke, Sherbrooke, QC, Canada, 2Imeka Solutions Inc, Sherbrooke, QC, Canada

How do we assure a diffusion MRI processing pipeline that is: i) deterministic, i.e. given two runs of the pipeline on the same data, the same output is returned, ii) reproducible in time, and iii) efficient? Diffusion MRI has several processing steps that may not be reproducible between multiple runs. This reproducibility varies because of the parameters, multi-threading and the versions of the tools used. Moreoever, processing time for a large database can take several hours when each step are ran sequentially. To solve these problems, we developed a reproducible and efficient diffusion MRI pipeline based on Nextflow and Singularity.

3581
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Diffusion Kurtosis Imaging of the Brain with Free Water Elimination
Teddy Salan1, Sulaiman Sheriff1, and Varan Govind1

1Radiology, Miller School of Medicine, University of Miami, Miami, FL, United States

In diffusion weighted imaging (DWI) of the brain, a single voxel may contain gray matter (GM), white matter (WM), as well as free water embedded in GM, WM, and cerebrospinal fluid (CSF), each with different diffusion profiles. Free water elimination (FWE) is a method used to separate the free water components from tissue water. In this work, we extend FWE by fitting with a diffusion kurtosis imaging (DKI) model as it is a better descriptor of the non-Gaussian diffusion that occurs in tissue water.

3582
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A Graph Theory and Spectral Graph Theory Approach to Correlating Tractography with Parkinson’s Disease.
Daniel DeYoung1, Manish Amin1, Catherine Price2, and Thomas Mareci1,3

1Physics, University of Florida, Gainesville, FL, United States, 2Clinical and Health Psychology, University of Florida, Gainesville, FL, United States, 3Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States

Diffusion imaging is a potentially powerful tool for analyzing the effect of Parkinson’s disease on the brain. DWI analysis may provide some insight into how Parkinson’s disease may affect low executive or low memory functioning in the brain on a structural level. This research aims to analyze the complexity of the brain connectivity using graph theory and spectral graph theory to correlate structural differences between the brains of Parkinson’s patients with low memory functioning or low executive functioning, and controls.


Diffusion in Disease

Exhibition Hall
Wednesday 9:15 - 10:15
 Diffusion

3583
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Multi-site diffusion MRI harmonization in the presence of gross pathology: How far can we push?
Suheyla Cetin Karayumak1, Marek Kubicki1, and Yogesh Rathi1

1Department of Psychiatry, Harvard Medical School, BOSTON, MA, United States

We present a multi-site diffusion MRI (dMRI) data harmonization method using CycleGAN network with segmentation loss (CycleGANS). This method aims to learn an efficient mapping of dMRI signal using rotation invariant spherical harmonics features from the same set of subjects across sites. At the same time, it has potential to learn the tumor pathology (if exists) during harmonization. We compare our CycleGANS network with the CycleGAN network.  We show that our CycleGANS network has better multi-site diffusion MRI data harmonization accuracy. Moreover, our method shows up to 60% improvement on the prediction of tumor pathology.

3584
Computer 77
Joint distribution of axonal length and diameter quantifies beading in traumatic brain injury
Dan Benjamini1,2, Michal E Komlosh1,2, Elizabeth B Hutchinson1, and Peter J Basser1

1National Institutes of Health, Bethesda, MD, United States, 2Center for Neuroscience and Regenerative Medicine, Bethesda, MD, United States

We present a novel diffusion MRI approach to measure the three-dimensional axonal morphology alterations following traumatic brain injury that results in beading, by modeling axons with a two-dimensional joint distribution of diameters and lengths ($$$D$$$-$$$L$$$). Here we study a segment of ferret spinal cord tissue with known and focal Wallerian degeneration of the corticospinal tract alongside an uninjured control. The results suggest that this approach can be used to specifically detect and quantify axonal beading.

3585
Computer 78
Quantitative Sodium Pump Activity, Cellularity, and Cytometry: In Vivo Analytical Pathology from DWI
Eric M. Baker1, Brendan Moloney1, Xin Li1, Gregory J. Wilson2, Thomas M. Barbara1, Jeffrey H. Maki3, Erin W. Gilbert4, and Charles S. Springer, Jr.1

1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 2Home, Mill Creek, WA, United States, 3Radiology, University of Colorado Denver, Aurora, CO, United States, 4Surgery, Oregon Health & Science University, Portland, OR, United States

With cellular ensembles featuring stochastic geometries, Monte Carlo random walk simulated DWI b-space decays exhibit sensitivity to cell biology parameters measuring membrane Na+,K+‑ATPase [NKA] activity, cell density, ρ, and voxel average cell volume, <V>.  Furthermore, the simulation matching the experimental in vivo human cerebral cortex b‑space decay has parameters [cellular water efflux rate constant <kio> = 2 s-1, ρ = 98,000 cells/μL, and <V> = 8.2 pL] in near absolute agreement with the most pertinent literature.  Inspecting the common, empirical early decay measure, ADC, of these simulations provides insights into acute and chronic tissue property changes in vivo.  

3586
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Investigation of relationships between systemic inflammation and brain structure in chronic obstructive pulmonary disease (COPD)
Mohani-Preet K Bajaj1, Sachelle Ruickbie2, Daniel R Burrage2, Catherine A Spilling3, Abhiram Prasad4, James Dodd5, Paul W Jones6, Emma H Baker6, and Thomas R Barrick3

1Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s Uni, Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s, University of London, London, United Kingdom, 2Institute for Infection and Immunity, St George's University of London, London, United Kingdom, Institute for Infection and Immunity, St George's, University of London, London, United Kingdom, 3Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s, University of London, Neurosciences Research Centre, Molecular and Clinical Research Institute, St George’s, University of London, London, United Kingdom, 4St George’s, University of London, London, United Kingdom, 5Academic Respiratory Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom, Bristol, United Kingdom, 6Institute for Infection and Immunity, St George's, University of London, London, United Kingdom

COPD patients have increased systemic inflammation and increased structural brain damage. 23 COPD patients with coronary artery disease (CAD), and 24 people without COPD matched for smoking, and CAD severity (Gensini score) were studied. COPD patients had more white matter lesions and microstructural tract abnormalities compared to controls. Systemic inflammation (high sensitivity C-reactive protein and fibrinogen) was associated with microstructural brain damage in whole-group analyses. These results suggest a systemic inflammatory process in COPD, which may contribute to white matter abnormalities, consistent with those reported in small vessel disease.

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Q-Space Trajectory Imaging to Untangle Sources of Microstructural White Matter Changes: Comparison of Schizophrenia Subjects and Healthy Controls
Ofer Pasternak1, Filip Szczepankiewicz1, Zora Kikinis1, Markus Nilsson2, Tomáš Kašpárek3,4, and Carl-Fredrik Westin1

1Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 2Lund University, Lund, Sweden, 3University Hospital Brno, Brno, Czech Republic, 4Masaryk University, Brno, Czech Republic

The recently proposed q-space trajectory imaging (QTI) analysis for multidimensional dMRI acquisitions with free wave forms quantifies domains of variability (size, shape, orientation) that can explain the sources of microstructural changes in the brain. These previously inaccessible domains are used here to disentangle differences observed in the white matter of schizophrenia patients compared to healthy controls. In this population microscopic anisotropy (shape variability) explains changes in fractional anisotropy, in agreement with a hypothesis of white matter degeneration. This study provides a first proof of principal for the feasibility of applying free wave form based sequences on a clinical population.

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Prostate Cancer Classification by Using Mono Exponential, Stretched Exponential and Kurtosis Model Parameters of Diffusion Signal Decay
Meltem Uyanik1,2, Rolf Rieter2, Michael Abern1, Winnie Mar3, Virgilia Macias4, Hari T. Vigneswaran1, and Richard L. Magin2

1Department of Urology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States, 2Richard and Loan Hill Department of Bioengineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States, 3Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States, 4Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States

Prostate cancer is the most common solid cancer occurring among men in the US. Diffusion-weighted MR imaging plays a complementary role to T2-weighted images in identifying regional changes in prostate tissue. Here, we fit the diffusion decay signal from patients using the stretched-exponential and the kurtosis models and compare the results with MR guided prostate biopsy histology. Our results showed that the kurtosis and stretched exponential models fit to multi-b values diffusion data have the potential to distinguish benign from malignant lesions. These model parameters identify tissue heterogeneity and structures that may be useful in the grading of prostate cancer. 

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Application of DTI and DWI quantitative parameters in differential diagnosis of uterine sarcoma and degenerated hysteromyoma
Miao Niu1, Ailian Liu1, and Lizhi Xie2

1The First Affiliated Hospital of Dalian Medical University, DaLian, China, 2GE Healthcare, MR Research, Beijing, China

To investigate the application of diffusion tensor imaging methods, including Diffusion Tensor Imaging(DTI) and Diffusion Weighted Imaging(DWI) in the differential disgnosis of uterine sarcoma and degenerated hysteromyoma. 

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To Detect Metastatic Lymph Nodes Using Intravoxel Incoherent Motion Diffusion-weighted Imaging: A Longitudinal Study on Animal Model
Liuji Guo1, Xiaodan Li1, Xiaomin Liu1, Zhiguang Si2, Jie Qin1, Yingjie Mei3, Zhongping Zhang3, Yikai Xu1, and Yuankui Wu1

1Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China, 2Department of Medical Imaging, People's Hospital of Dehong Prefecture, Yunnan, China, 3Philips Healthcare, Guangzhou, China

Lymph node (LN) involvement is a dynamic process which may be reflected by intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI). However, there is no such studies so far. Therefore, the potential influence on the diagnosis performance for metastatic LN needs to be investigated. In this longitudinal study on animal models, metastatic LNs evolved in a different pattern from inflammatory LNs pathologically, and IVIM parameters differed between the two groups at particular time points. This indicates that IVIM-DWI can reflect the dynamic pathological changes of LN diseases, and its ability to detect metastatic LN may be affected by the course of disease.

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Apparent Diffusion Coefficient Using Diffusion Weighted MRI and Biochemical Correlates in  Human Breast Cancer
Kavya Umachandran1, Andres Saucedo1, Stephanie Lee-Felker1, Melissa M Joines1, Manoj Kumar Sarma1, Sumit Kumar1, Maggie DiNome2, Nanette DeBruhl1, and Michael Albert Thomas1

1Radiological Sciences, UCLA Geffen School of Medicine, Los Angeles, CA, United States, 2Surgery, UCLA Geffen School of Medicine, Los Angeles, CA, United States

Multiparametric MRI has been investigated in breast and prostate cancer, and other tumors. We evaluated diffusion weighted imaging in a pilot cohort of 20 malignant and 11 benign breast cancer patients, and 7 healthy women. MR spectra were recorded using an accelerated version of five dimensional echo-planar correlated spectroscopic imaging (5D EP-COSI). Significant decline in ADC values of malignant breast cancer compared to benign and healthy women. There was a negative correlation of choline with ADC values in malignant cancer patients. Our findings suggest that choline and lipids can be reliable biomarkers in addition to widely used ADC.

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Diffusion Tensor Imaging of Phenylketonuria (PKU) Mouse Brain White Matter Integrity
Xia Ge1, Zoe W Hawks2, Desiree A White2, Auro Ferreiro3, Gautam Dantas3, John Engelbach1, Joshua S Shimony1, and Joel R Garbow1,4

1Mallinckrodt Institute of Radiology, Washington University, St Louis, MO, United States, 2Department of Psychological and Brain Sciences, Washington University, St Louis, MO, United States, 3The Edison Family Center for Genome Sciences & Systems Biology and Department of Biomedical Engineering, Washington University, St Louis, MO, United States, 4Alvin J Siteman Cancer Center, Washington University, St Louis, MO, United States

DTI was used to evaluate brain white-matter integrity and development in Pahenu2 mice, a model of phenylketonuria (PKU). At two months of age, the volume of the CC in Pahenu2 mice was smaller than that of C57Bl6 controls, and the FA of white matter is significantly lower. For PKU mice on a low-Phe diet, both Daxial and FA of CC and IC increased from two to four months, while these metrics decreased in Pahenu2 mice on a normal diet, suggesting a loss of axonal integrity. Our data suggest that Phe levels are critical to white-matter development in Pahenu2 mice.

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Apparent diffusion coefficient: Early Indicator of Atheroembolic Renal Disease
Bihui Zhang1, Min Yang1, Guochen Niu1, Ziguang Yan1, Yinghua Zou1, Xiaoqiang Tong1, and Xiaoying Wang1

1Peking University First Hospital, Beijing, China

Atheroembolic Renal Disease (AERD) is part of a multisystemic disease and has a strong clinical impact on patient and renal survival. Its early diagnosis has a valuable prognostic meaning and huge impact on treatment planning. The tissue edema in early-stage AERD makes DWI a perfect tool for early diagnosis of AERD. In this study, we investigated the role of DWI to noninvasively detect AERD as well as the correlation between ADC values and disease severity identified by histology in an early stage.  

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Longitudinal evaluation of bundle-wise water diffusion changes following axonal degeneration in a region of fiber crossing
Omar Narvaez1, Ricardo Coronado-Leija1, Gilberto Rojas-Vite1, Marcos Aranda2, Alonso Ramirez-Manzanares3, Jose Luis Marroquin3, Jorge Larriva-Sahd1, and Luis Concha1

1Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Queretaro, Mexico, 2Escuela de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina, 3Centro de Investigacion en Matematicas, Guanajuato, Mexico

Axonal degeneration is a hallmark of many neuropathologies, with a defined time course presenting distinct histological features. In single fiber regions, the tensor model provides reliable information in early and chronic phases of axonal damage. However, said model cannot accurately determine per-bundle characteristics in voxels occupied by axonal populations with different orientations. We evaluated two multiple-fiber methods in an animal model of axonal degeneration (unilateral retinal ischemia) to provide information about the sensitivity of these models related to microstructural changes occuring in the acute and early chronic stages of pathology in a crossing fiber region.

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Towards MR-based interrogation of the hypoxia-driven insulin resistance mechanism: Adipocytes size estimation.
Darya Morozov1, Alexander L. Sukstanskii1, and Scott C. Beeman1

1Radiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, United States

It has been suggested that adipocyte hypertrophy plays a key role in the pathogenesis of systemic insulin resistance and type 2 diabetes. A method for quantifying adipocyte size/hypertrophy in-vivo would be a major advance towards understanding the pathogenesis of type 2 diabetes. In-vivo quantification of adipocyte size might be achievable using short time regime diffusion MR, which carries information about size of the system. Herein, we explore the feasibility of measuring adipocyte size based on the diffusion of triglyceride within adipocytes and the principles of the short diffusion time regime.

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Decoupling effects of fiber dispersion and microscopic anisotropy fundamentally change interpretations of DTI in multiple sclerosis
Kasper Winther Andersen1, Samo Lasič1,2, Henrik Lundell1, Markus Nilsson3, Daniel Topgaard4, Filip Szczepankiewicz5,6,7, Hartwig Roman Siebner1,8,9, Morten Blinkenberg10, and Tim B Dyrby1,11

1Copenhagen University Hospital Hvidovre, Danish Research Centre for Magnetic Resonance, Hvidovre, Denmark, 2Random Walk Imaging, AB, Lund, Sweden, 3Clinical Sciences, Lund, Department of Radiology, Lund University, Lund, Sweden, 4Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden, 5Medical Radiation Physics, Lund University, Lund, Sweden, 6Harvard Medical School, Boston, MA, United States, 7Radiology, Brigham and Women’s Hospital, Boston, MA, United States, 8Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark, 9Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark, 10Danish Multiple Sclerosis Center, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark, 11DTU Compute, Technical University of Denmark, Lyngby, Denmark

Fractional anisotropy from diffusion tensor imaging (DTI-FA) has frequently been used to probe changes in white matter microstructure, but is also heavily affected by axonal fiber dispersion. μFA removes fiber dispersion effects and thereby estimates the microscopic anisotropy. Here, we found lower μFA in normal appearing white matter in multiple sclerosis patients as compared with healthy controls. In addition, μFA correlated significantly with age, disability and cognitive performance. These relations could not be established with DTI-FA. Our results indicate that μFA could be used as a powerful biomarker for diseases related to micro-structural changes in white matter as well as in studies of the healthy brain.


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A Novel Characterization of Traumatic Brain Injury in White Matter with Diffusion MRI Spherical-Harmonics Rotation Invariants
Mauro Zucchelli1, Drew Parker2, Samuel Deslauriers-Gauthier1, Junghoon John Kim3, Ragini Verma2, and Rachid Deriche1

1Athena Project-Team, INRIA, Sophia Antipolis - Méditerranée, France, 2University of Pennsylvania, Philadelphia, PA, United States, 3Department of Molecular, Cellular, and Biomedical Sciences, CUNY School of Medicine, New York, NY, United States

The current DTI-based markers of traumatic brain injury are able to capture affected white matter in the brain, but miss the areas of crossing fibers due to the simplicity of the model. In this work, we use a novel set of spherical-harmonics rotation invariants indices, recently proposed in the literature. We demonstrate that these 12 invariants capture all the information provided by DTI and, in addition, they capture differences in complex white matter beyond DTI measures. This, combined with the clinical feasibility of the method, paves the way for them to be used as better markers of brain injury.

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Multi-site concordance of diffusion weighted imaging derived metrics, a comparison of fitting algorithms for differentiating whole-mount, pathologically confirmed, prostate cancer of differing Gleason patterns
Peter S LaViolette1, Sean D McGarry2, John D Bukowy1, Allison K Lowman1, Anjishnu Banerjee3, Dariya Malyarenko4, Tom Chenevert4, Yue Cao4,5, Andrey Fedorov6, Laura Bell7, C. Chad Quarles7, Melissa Prah2, Kathleen Schmainda2, Stefanie Hectors8, Bachir Taouli8, Eve LoCastro9, Yousef Mazaheri9,10, Amita Shukla-Dave9,10, Thomas Yankeelov11, David A Hormuth II11, Ananth J Madhuranthakam12, Keith Hulsey12, Kurt Li13, Wei Huang13, Mark Muzi14, Kenneth Jacobsohn15, Mark Hohenwalter1, Petar Duvnjak1, Michael Griffin1, William See15, Marja Nevalainen16, and Kenneth A Iczkowski16

1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 2Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 3Biostatistics, Medical College of Wisconsin, Milwaukee, WI, United States, 4Radiology, University of Michigan, Ann Arbor, MI, United States, 5Radiation Oncology, University of Michigan, Ann Arbor, MI, United States, 6Radiology, Brigham and Women's Hospital, Boston, MA, United States, 7Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, 8Radiology, Mount Sinai, New York, NY, United States, 9Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 10Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 11Institute for Computational Engineering and Sciences, University of Texas, Austin, TX, United States, 12Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 13Advanced Imaging Research Center, Oregon Health Sciences University, Portland, OR, United States, 14Department of Radiology, University of Washington, Seattle, WA, United States, 15Urological Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, 16Pathology, Medical College of Wisconsin, Milwaukee, WI, United States

We present a multi-site study measuring the ability of various software platforms to fit diffusion weighted imaging (DWI) models for differentiating prostate cancer (PCA) of different Gleason patterns. A dataset of DWI collected from 33 PCA patients was distributed to ten collaborating groups who fit the multi-b DWI models with onsite software and submitted the derived parametric maps to a central analysis site. Each map was aligned to the T2-weighted image and compared to pathologist annotations of whole-mount prostate samples. A statistical analysis was performed for similarity of the quantitative values, and the ability of each metric to differentiate PCA.

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Optimizing Imaging Protocols for Structural Connectomics in Mouse Models of Neurological Conditions
Robert J Anderson1, Christopher Long1, Evan D Calabrese2, Scott H Robertson1, Gary P Cofer1, G Allan Johnson1, and Alexandra Badea1

1Radiology, Duke University Medical Center, Durham, NC, United States, 2Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States

Network approaches provide sensitive biomarkers for neurological conditions such as Alzheimer’s disease. Mouse models provide tools to dissect vulnerable circuits at prodromal stages, and to assess the effects of interventions. We have simulated mouse brain structural connectomes, balancing angular, spatial resolution and scan time. Specifically, we evaluated protocols with 6, 12, 15, 20, 30, 45, 60 and 120 angles; and 3 voxel sizes at 43, 86 and 172 µm. Our results indicate schemes using 46 or 60 diffusion directions, acquired at 86 µm resolution achieve a good cost/performance balance relative to a high spatial, high angular resolution sampling scheme.

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THE EFFECT OF MATERNAL OXYGENATION ON PLACENTAL PERFUSION IN NORMAL GROWTH AND FETUS GROWTH RESTRICTED FETUSES BY USING IVIM MRI
Ting Chen1, Xuanyi Zhou2, and Yongming Dai2

1Radiology Department, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, 2MR Collaboration, United Imaging Healthcare, Shanghai, China

The aim of this study was to determine whether IVIM-MRI could evaluate oxygen inhalation therapy in placental perfusion during maternal hyperoxygenation in FGR and normal growth fetuses. 

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Free Water Characterization of Peritumoral Regions in Primary and Secondary Brain Neoplasms
Abdol Aziz Ould Ismail1, Drew Parker1, Simon Alexander2, Steven Brem3, and Ragini Verma1

1Penn Patho-Connectomics Lab, Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Synaptive Medical, Victoria, BC, Canada, 3Neurosurgical Oncology, University of Pennsylvania, Philadelphia, PA, United States

There is a growing interest in characterizing the peritumoral regions in neoplasms, in order to distinguish primary and secondary neoplasms, improve tractography for surgical planning, and create radiomic markers of infiltration. Free water estimation is expected to reflect the differences in water content of the peritumoral region between these tumor types. In this work, we compare glioblastoma (primary) and metastatic (secondary) tumors based on their free water estimated using standard clinical diffusion MRI (dMRI). Results demonstrate significant difference in these tumor types based on the free water measures, fractional anisotropy post-correction and the coverage of the peritumoral region by tractography. 

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Diffusion Weighted MRI Characterization of Effects of Sex and APOE Genotype in a Mouse Model
Loi Vinh Do1, Adam Scott Bernstein1, Aarti Mishra2,3, Maunil K Desai2, Marc Lindley1, Chidi Ugonna1, Nan-kuei Chen1, Roberta Brinton3,4, and Theodore Trouard1

1Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 2Department of Clinical Therapeutics, USC School of Pharmacy, University of Southern California, Los Angeles, CA, United States, 3Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States, 4Department of Pharmacology, University of Arizona, Tucson, AZ, United States

Structural and diffusion MRI (dMRI) analyses can be used to characterize neurodegeneration during Alzheimer’s disease progression. Male and female mice with a targeted replacement of mouse APOE gene with humanized APOEε3 or APOEε4, underwent behavioral, transcriptomic and imaging analyses. Postmortem MRI of fixed brains included high resolution T2-weighted and diffusion weighted imaging. Structural volume assessment revealed that APOE genotype and sex have a significant impact on regional brain volumes. dMRI quantified white matter microstructural differences between APOEε3 or APOEε4 females/males which maybe cross-validated with  transcriptomic and behavioral findings. Further confirmation of microstructural assessment is pending by electron micrographs. 

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MRI Assessment of Sex Differences in APOEε4 Knock-in in Rat Brains
Loi Vinh Do1, Aarti Mishra2,3, Adam Scott Bernstein1, Marc Lindley1, Chidi Ugonna1, Nan-kuei Chen1, Roberta Brinton3,4, and Theodore Trouard1

1Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 2Department of Clinical Therapeutics, USC School of Pharmacy, University of Southern California, Los Angeles, CA, United States, 3Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States, 4Department of Pharmacology, University of Arizona, Tucson, AZ, United States

Using a humanized APOEε4 gene knock-in ex-vivo rat brain model, the individual and combined impact of sex and APOEε4 genotype on white matter microstructure was measured using high T2-weighted and diffusion weighted MRI. Total brain volumes showed a significant sexual dimorphism in WT as well as APOEε4 animals, with the females having significantly lower volumes. Both volumetric and diffusion MRI measures were able to show trends of sexual dimorphism as well as genotype effect. These findings were supported with metabolomic data suggesting reduction in glucose utilization and possible shift to fatty acids derived from white matter catabolism as a fuel source.

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Multicomponent Analysis of High b-value Diffusion-Weighted MRI for Tracking Progression of Amyotrophic Lateral Sclerosis in A Mouse Model
Jin Gao1,2, Mingchen Jiang3, Richard Magin4, Andrew Larson5, and Weiguo Li2,4,5

1Department of Electrical & Computer Engineering, University of Illinois at Chicago, Chicago, IL, United States, 2Research Resources Center, University of Illinois at Chicago, Chicago, IL, United States, 3Department of Physiology, Northwestern University, Chicago, IL, United States, 4Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 5Department of Radiology, Northwestern University, Chicago, IL, United States

Amyotrophic lateral sclerosis (ALS) is a progressive disease of motor neuron degeneration in brain and spinal cord with an unknown etiology. Diffusion MRI has potential to track the disease progression in ALS due to the technique’s intrinsic advantages in detecting structure changes and non-invasive nature. In this study, we investigated the feasibility of analyzing multiple high b-value diffusion-weighted images using a non-negative least squares method (requiring no prior assumptions about components) and a bi-compartment model with restricted and hindered diffusion components. Both methods were able to detect alterations of spinal cord in the G93A-SOD1 mouse model of ALS.

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High B-value In-vivo DTI for Early Detection of Cerebral Microstructure Alteration: Application to Hippocampus Lesions in a Mouse Model of Multiple Sclerosis
Renaud NICOLAS1, Amandine CROMBE2,3, Nathalie RICHARD4, Thomas TOURDIAS2,3, and Bassem HIBA4

1INCIA, Université de Bordeaux, CNRS, Bordeaux, France, Metropolitan, 2Neurocentre Magendie, INSERM, U1215, Bordeaux, France, Metropolitan, 3CHU de Bordeaux, Bordeaux, France, Metropolitan, 4Institut des sciences cognitives Marc Jeannerod, UMR 5229, CNRS-université Lyon1, Bron, France, Metropolitan

Few reports have highlighted the value of DTI achieved with a strong water-diffusion weighting to capture early and diffuse changes in cerebral microstructure of the white-matter. This study investigates the benefit of DTI with b-value=2700s/mm² to detect microstructure lesions of the hippocampus in a mouse model of multi-sclerosis. High b-value DTI allowed to detect microstructure changes invisible using DTI achieved with classical b-value=1000s/mm². In grey-matter tissues with complex architecture such as hippocampus, an increase of b-value appeared to be more relevant to monitor the microstructure changes compared to an increase of the number of diffusion directions.

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Diffusional Kurtosis Imaging of Temporal Lobe Gray Matter as a Biomarker of Neurological Disease: Schizophrenia and Autism Spectrum Disorder
Faye McKenna1,2, Laura Miles1, Jeffrey Donaldson1, F. Xavier Castellanos3, Donald Goff3, and Mariana Lazar1

1Radiology, Center for Biomedical Imaging, New York, NY, United States, 2Sackler Institute of Graduate Biomedical Sciences, New York, NY, United States, 3Psychiatry, New York University School of Medicine, New York, NY, United States

In this study, we employed diffusion kurtosis imaging (DKI) to test for differences in gray matter (GM) microstructure in schizophrenia (SZ) and autism spectrum disorder (ASD). Significantly increased metrics of DKI were found in SZ compared to HC participants, while significantly decreased metrics of DKI were found in ASD compared to HC in the temporal lobe and sub-lobar temporal regions of interest (ROIs). In vivo DKI metrics appear to be sensitive to GM microstructural pathology in SZ and ASD and may provide new information on the neural underpinnings of these disorders.


Microstructure Modeling: 2

Exhibition Hall
Wednesday 9:15 - 10:15
 Diffusion

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Resting-state diffusion fMRI bears strong resemblance and only subtle differences to BOLD fMRI
Ileana Ozana Jelescu1

1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

Diffusion fMRI (dfMRI) is a presumably non-BOLD technique sensitive to transient microstructural changes underlying neural activity. Previous task-fMRI studies have assessed the characteristics of the dfMRI signal and potential BOLD contamination, with conflicting results.  Here we acquired resting-state fMRI data with five protocols with incrementally reduced BOLD contributions and analyzed the characteristics of resting-state networks and functional connectivity using model-free approaches. We report dfMRI data does not contain fundamentally different information to BOLD-fMRI, with the exception of a few regions that switch from anti- to positively-correlated. Future work will focus on removing any remaining BOLD contribution from the dfMRI acquisition.

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Diffusion Kurtosis Image in assessment of 3D Cell Culture
Jui-Heng Lin1, Huei-Chun Hsiao1, Shao-Chieh Lin1, Yi-Jui Liu2, Ruey-Hwang Chou3, Ke-Sin Yan3, Tan-Wei Liao3, Chao-Chun Lin4, Chia-Wei Lin4, and Wu-Chung Shen4

1Master's Program of Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung, Taiwan, 2Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, 3Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan, 4Department of Radiology, China Medical University Hospital, Taichung, Taiwan

A non-Gaussian kurtosis model has been shown to take into account tissue heterogeneity and two relative imaging biomarkers namely, the kurtosis coefficient and the corrected diffusion coefficient can be quantified. In this study, 3D cell culture with hydrogels ECM was used to investigate whether DKI may provide information on these microenvironmental parameters and the microenvironment-associated metastatic propensity of tumors. Our results demonstrated DKI-MRI may provide the potential biomarkers on the change of microenvironment in the application of 3D cell culture experiment.

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Does cerebrospinal fluid pulsation affect DWI thermometry?: healthy volunteer study
Koji Sakai1, Jun Tazoe1, Hiroyasu Ikeno2, Kentaro Akazawa1, Masashi Yasuike1, Toshiaki Nakagawa2, Bárbara Schmitz Abecassis1, and Kei Yamada1

1KPUM, Kyoto, Japan, 2KPUM Hospital, Kyoto, Japan

Diffusion-weighted imaging (DWI) based thermometry has a potential to be a non-invasive method of temperature measurement for the deep inside of human brain. Nevertheless, the DWI at lateral ventricle in the brain might be influenced by the pulsation flow of cerebrospinal fluid (CSF), which is motivated by heartbeat. The purpose of this study was to investigate the influence of pulsation flow on brain DWI thermometry for healthy subjects. Comparisons were performed among  ΔT at three CSF speed selections (slow vs. fast vs. random). There was no significant difference in ΔT among the CSF speed and volume on healthy subjects.

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Abnormal cerebellar connectivity within the motor subnetwork in MSA with cerebellar dysfunction
Apurva Shah1, Shweta Prasad2, Santosh Dash3, Jitender Saini4, Pramod Kumar Pal3, and Madhura Ingalhalikar1

1Symbiosis Centre of Medical Image Analysis, Symbiosis International University, Pune, India, 2Department of Clinical Neurosciences and Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India, 3Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India, 4Department of Neuroimaging & Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, India

Multiple system atrophy with cerebellar features (MSA-C) is a distinct subtype of MSA characterized by predominant cerebellar symptoms. Neuroimaging studies have demonstrated cerebellar abnormalities; however, abnormality of structural connectivity of the motor subnetwork has not been studied and this study aims to investigate this aspect. We observed impairment in the structural segregation, integration and network resilience with significantly reduced nodal strength and connectivity in several cerebellar as well as non-cerebellar regions that correlate with UMSARS scores. Our findings provide definitive evidence of abnormalities that may be causally implicated in the motor features of cerebellar dysfunction and Parkinsonism observed in MSA-C.

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Propagation of Bias in Moment-Matching Based Standard Model Parameter Estimation
Jonas Lynge Olesen1,2, Noam Shemesh3, and Sune Nørhøj Jespersen1,2

1Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, 2Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark, 3Champalimaud Neuroscience Programme, Lisbon, Portugal

Moment-matching is one proposed approach for estimating Standard Model parameters which partly overcomes the issues of the model’s notoriously shallow fitting landscape. The method achieves robustness by matching the model’s moments to the cumulants of the data determined by diffusion kurtosis imaging which is stable and clinically feasible. However, estimates of cumulants generally suffer from bias due to the use of finite b-values. Here, it is demonstrated that this bias propagates to the model-parameter estimates resulting in substantial inaccuracy even for small b-values.

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Random Walks in Stochastic Geometries
Eric M. Baker1, Brendan Moloney1, Xin Li1, Erin W. Gilbert2, and Charles S. Springer1

1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 2Surgery, Oregon Health & Science University, Portland, OR, United States

Monte Carlo random walk simulations of water molecule displacements in realistic cell ensembles are presented.  Within an ensemble, the cells have stochastic distributions of sizes, shapes, and interstitial spacings.  The probability of molecules permeating the cell membrane is varied.  The irreducible, fundamental system parameters are the cell density, ρ, the mean cell volume, <V>, and the steady-state cellular water efflux rate constant, <kio>.  Even though the self-diffusion coefficient is that of pure water, non-Gaussian displacements are observed.  

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Characterising tissue heterogeneity in cerebral metastases using multi-shell multi-tissue constrained spherical deconvolution
Maxime Chamberland1, Najmus Sahar Iqbal1,2, Suryanarayana Umesh Rudrapatna1, Greg Parker1, Chantal M.W. Tax1, John Staffurth2,3, James Powell2, Richard Wise1, and Derek K. Jones1,4

1School of Psychology, Cardiff University Brain Research Imaging Centre, Cardiff, United Kingdom, 2Velindre University NHS Trust, Velindre Cancer Centre, Cardiff, United Kingdom, 3Department of Cancer and Genetics, Cardiff University School of Medicine, Cardiff, United Kingdom, 4School of Psychology, Australian Catholic University, Victoria, Australia

Considerable attention has focused on characterizing brain tumours using diffusion tensor imaging, and only more recently using advanced modelling techniques. Building on the observation that metastatic tumors exhibit different signal intensities depending on their histological/cellular composition, we investigate how multi-shell multi-tissue constrained spherical deconvolution can characterise tissue heterogeneity within brain metastases.

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Reproducibility of tractography based on fibre orientation distribution and anatomical constraints applied on paediatric diffusion MRI.
Thanh Vân Phan1,2, Thibo Billiet2, Dirk Smeets2, and Maaike Vandermosten1

1ExpORL, KU Leuven, Leuven, Belgium, 2Research and Development, icometrix, Leuven, Belgium

Tractography is known to be sensitive to technical variations but might also be sensitive to issues related to paediatric data, such as head motion. We assessed the reproducibility in paediatric data of the probabilistic tractography algorithm based on fibre orientation distribution and anatomical constraints that enables to deal with crossing fibres and to reconstruct tracts with more anatomical accuracy. Our results showed that the reproducibility of this approach when it is applied on paediatric data is negatively affected by younger age and by head motion but can still achieve good reproducibility for selected tracts.

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Cardiac Fiber Mobility During Contraction Using High Resolution Diffusion Tensor MRI
Kevin Moulin1, Ilya A Verzhbinsky1, Tyler E Cork1, Nyasha Maforo2,3, Luigi E Perotti2,4, and Daniel B Ennis1

1Radiological Sciences Lab, Department of Radiology, Stanford University, Stanford, CA, United States, 2Department of Radiological Sciences, University of California, Los Angeles, CA, United States, 3Physics and Biology in Medicine IDP, University of California, Los Angeles, CA, United States, 4Department of Bioengineering, University of California, Los angeles, CA, United States

The main cardiomyocyte aggregate orientation, represented by the Helix Angle, remains poorly described in vivo during contractionas it is affected by the imaging resolution and thus by a change of wall thickening. This work evaluated the effect of the imaging resolution using a numerical phantom and ex vivoscans on porcine hearts. High-resolution cDTI was acquired in vivoto measure the transmural mobility of Helix Angle at three cardiac phases. A strong steepening of Helix Angle was observed as the resolution decreased in simulation and ex-vivo. A significant change in the Helix Angle distribution was observed during contraction. 

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Metabolite diffusion weighted imaging with golden angle radial echo planar spectroscopic imaging
Vincent Oltman Boer1, Itamar Ronen2, Jan Ole Pedersen3, Esben Thade Petersen1,4, and Henrik Lundell1

1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 2C.J. Gorter Center for High Field MRI Research, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 3Philips Healthcare, Copenhagen, Denmark, 4Center for Magnetic Resonance, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark

Diffusion weighted spectroscopy (DWS) is a promising tool for investigating compartment specific microstructure in heterogeneous tissues. Unlike water abundant in all cellular spaces, the mobility of metabolites provides a window into the microstructure of specific cell types. Multi-shot sequences for diffusion spectroscopic imaging suffer from translation induced phase fluctuations. This has previously been addressed with additional phase navigators. In this work we propose self navigated metabolite diffusion weighted spectroscopic imaging using golden angle radial echo planar gradient readouts with semi-LASER voxel localization. Initial data shows good spatial localization and spectral quality.

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Needle in a Haystack: Finding connections of interest in the precentral gyrus from diffusion MRI based connectomics
Jasmeen Sidhu1, Francois Rheault2, and Maxime Descoteaux2

1Département de médecine nucléaire et radiobiologie, Université de Sherbrooke, Sherbrooke, QC, Canada, 2Université de Sherbrooke, Sherbrooke, QC, Canada

DMRI tractography and connectomics aim to create comprehensive maps of all neural circuitry in the brain, however, dMRI is a false-positive prone imaging modality. Yet, as it is the only non-invasive and in-vivo method to indirectly study the white matter connectivity of the brain it is heavily utilized. DMRI-Connectomic analyses often end with a “big data” problem, as there are many possible connections. Moreover, this data is likely populated by false-positive connections. By utilizing data-driven criteria to filter matrices this work attempts to narrow the “search window” by adding criteria on which we can discard “connections” or consider them potential candidates for further investigation. Such judgements may also lead to connections being evaluated as true or false-positives.

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Characterization of white matter asymmetries in the healthy human brain using diffusion MRI fixel-based analysis
Arush Honnedevasthana Arun1,2, Robert E Smith1, Alan Connelly1,2, and Fernando Calamante2,3,4

1Florey Institute of Neuroscience and Mental Health, Melbourne, Australia, 2Florey Department of Neuroscience and Mental health, Melbourne, Australia, 3The University of Sydney, Sydney Imaging, Sydney, Australia, 4The University of Sydney, School of Aerospace, Mechanical and Mechatronic Engineering, Sydney, Australia

The diffusion tensor model has been used extensively to study asymmetry in various regions of the human brain white matter. However, given the limitations of the tensor model, the nature of any underlying asymmetries remain uncertain, particularly in crossing fibre regions. Here, we applied fixel-based analysis (FBA) to state-of-the-art diffusion MRI data to assess white matter asymmetry of the healthy brain, demonstrating significant left/right asymmetries in various regions. The major advantage of this study is that FBA performs fibre-tract-specific modeling, and thus provides a method to assess the white matter asymmetry in a physically interpretable way.

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Toward prognostic sensitivity of DTI to cognitive outcomes following physical exercise interventions.
Anna Rita Egbert1, Ryan Falck1, John Best1, and Teresa Liu-Ambrose1,2

1Aging, Mobility and Cognitive Neuroscience Laboratory, University of British Columbia, Vancouver, BC, Canada, 2Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute and University of British Columbia, Vancouver, BC, Canada

Diffusion Tensor Imaging (DTI) is widely implemented in clinical research, yet, its prognostic value in brain and cognitive health remains uncertain. Prospective estimation of the effectiveness of interventions, such as physical exercise, can increase cost-effectiveness of treatment, thus, maximizing the impact of accessible modifiable preventive factors in improving health outcomes in the general population. We examined DTI in relationship to cognitive outcomes of physical activity intervention. This is the first study to show that white matter integrity related to sleep efficiency can be an early predictor of the cognitive outcomes of physical exercise intervention.

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Assessment of Microstructural Changes Induced via Repeated Videogame Training as a Measure of Neuroplasticity in Normal Developing, College-age Brains
Austin Patrick1, Douglas Dean1, Thomas Gorman2, C. Shawn Green1, and Andrew Alexander1

1University of Wisconsin-Madison, Madison, WI, United States, 2Indiana University-Bloomington, Bloomington, IN, United States

In this study, diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) were used to assess brain changes in white matter regions as a result of repeated videogame training. In a cohort playing a simulated race car game, we observe evidence of microstructural changes in tracts associated with working and long-term memory. Subjects playing a guitar simulation game, experienced changes in regions associated with attention, visuomotor learning, and proprioception of the limbs. This study demonstrates that diffusion MRI is promising for characterizing subtle brain changes associated with learning. 

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Finding the Surrogate Biomarkers of Glioma Infiltration in the Normal Appearing White Matter adjacent to Tumor using Neurite Orientation Dispersion and Density Imaging (NODDI)
Yi-Cen Ting1, Chou-Ming Cheng2, and Tzu-Chen Yeh3

1Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan, 2Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei Veterans General Hospital, Taipei, Taiwan, 3Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan

This work addresses the study in glioma, where Diffusion Tensor Imaging (DTI) provides incoherent information while Neurite orientation dispersion and density imaging (NODDI) may improve the microstructural characterization. Glioma recurrences are mostly located at the margin of the resection cavity as peritumoral area. NODDI, using a compartment-based biophysical model, would potentially provide specific surrogate biomarkers for the microscopic foci of glioma infiltration better than DTI. NODDI reveals that glioma cells can extend beyond the bulk tumor and peritumoral edema into normal appearing white matter (NAWM) adjacent to tumor or peritumoral edema by using Region of Interest (ROI)-based statistics.

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Assessing inter-vender reproducibility of diffusion tensor imaging of the spinal cord for multi-center imaging studies
Mitsuhiro Kitamura1, Satoshi Maki1, Takeo Furuya1, Takuya Miyamoto1, Yasuhiro Shiga1, Kazuhide Inage1, Sumihisa Orita1, Koji Matsumoto2, Shingo Terakado3, Yoshitada Masuda2, and Seiji Ohtori1

1Orthopedic Surgery, Chiba University Graduate School of Medicine, Chiba City, Japan, 2radiology, Chiba University Hospital, Chiba City, Japan, 3radiology, Asahi General Hospital, Asahi City, Japan

 In this study, we assessed the inter-vendor precision of diffusion tensor imaging (DTI) metrics using consensus acquisition protocol across 3T scanners from 3 main vendor at the two sites. The data were acquired from the traveling human healthy volunteer. DTI data and anatomical images were also acquired and imaging data were processed using the Spinal Cord Toolbox (SCT). Relatively higher inter vender reproducibility of fractional anisotropy (FA) in and cross-sectional area were demonstrated and it is considered feasible to conduct multicenter DTI studies of the spinal cord using FA value as biomarker and SCT as postprocessing tool.

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Performance of Intravoxel incoherent motion (IVIM) imaging in the curative effect evaluation of diabetic nephropathy - A preliminary study
Jing Chen1, Xirong Zhang1, Nan Yu1, Qi Yang1, Yong Yu1, Robert Grimm2, and Shaoyu Wang3

1AFFILIATED HOSPITAL OF SHAANXI UNIVERSITY OF CHINESE MEDICINE, Xianyang, China, 2Siemens Healthcare, Erlangen, Germany, 3MR Scientific Marketing, Siemens Healthcare, Xi'an, Xi'an, China

Diabetes has nowadays become one of the major public health problems. Early detection and intervention is crucial to delay the progress of Diabetic kidney disease. In this study, IVIM imaging was used to evaluate the renal-cortex- and medulla-related parameter changes before and after the treatment of diabetic nephropathy. It was found that after treatment, D, f, D *and ADC values were increased, indicating the improved microvascular perfusion.

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Diffusion MRI characterization of Proton-therapy-induced brain tissue changes: a case study
Lisa Novello1, Nivedita Agarwal1,2,3, Stefano Lorentini2, Sabina Vennarini2, Domenico Zacà1, Ofer Pasternak4, and Jorge Jovicich1

1CIMeC - Center for Mind/Brain Sciences, University of Trento, Trento, Italy, 2Proton-Therapy Unit, S. Chiara Hospital, APSS, Azienda Provinciale per i Servizi Sanitari, Trento, Trento, Italy, 3Radiology Unit, Santa Maria del Carmine Hospital, Rovereto (Trento), Italy, 4Departments of Psychiatry and Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States

Radiotherapy-induced neurotoxicity may be life threatening and its characterization is crucial for cancer treatment management, especially in early treatment phases. Diffusion MRI allows to assess non-invasively microstructural changes occurring with radiation treatment, which are of interest in relation to local absorbed dose and cognitive changes. Proton therapy (PT) offers the promise of more focal tumor damage relative to conventional radiotherapy. However, few studies have evaluated how it affects brain microstructure. As part of an ongoing longitudinal study, we present the first available data of 5 acquisitions along PT course showing a possible treatment-related “necrosis-like” effect  during treatment.

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Diffusion-Relaxation Imaging with B-tensor Encoding using the Cumulant Expansion
Carl-Fredrik Westin1, Filip Szczepankiewicz1, Lipeng Ning1, Yogesh Rathi1, and Markus Nilsson2

1BWH Radiology, Harvard Medical School, Boston, MA, United States, 2Department of Radiology, Lund University, Lund, Sweden

Quantitative T2 and diffusion imaging provide important information about tissue microstructure. However, a joint knowledge of quantitative T2 and diffusion-derived measures can provide richer information about the microstructure that is not accessible when using these modalities independently. The standard approach for estimating the joint distributions of the T2-diffusion relies on the inverse Laplace transform. This transform is known to be unstable and difficult to invert.  In this work, we introduce an alternative approach based on cumulant expansion, and extend the recently proposed multidimensional diffusion MRI framework ``Q-space Trajectory Imaging" (QTI) to include T2-relaxation modeling. The cumulants of the expansion include estimates of mean diffusion and T2 relaxation, as well as their variance and covariance. We demonstrate the feasibility of this approach in a healthy human brain.

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Qualitative Comparison of Calculated and Measured Ultra-High b-Value Diffusion-Weighted Images in the Assessment of Clinically Significant Prostate Cancer.
David Bonekamp1, Christopher Edler1, Jan Philipp Radtke1,2, Frederik Bernd Laun3, Markus Hohenfellner2, Heinz-Peter Schlemmer1, and Tristan Anselm Kuder4

1Radiology, German Cancer Research Center, Heidelberg, Germany, 2Urology, University Hospital Heidelberg, Heidelberg, Germany, 3MR Physics, University Hospital Erlangen, Erlangen, Germany, 4Medical Physics, German Cancer Research Center, Heidelberg, Germany

To qualitatively compare measured and calculated ultra-high b-value (UHB, b-value up to 4000 s/mm2) DWI for detection of clinically significant prostate cancer. UHB-DWI was acquired in 55 patients at 3T in addition to standard DWI (S-DWI) extrapolated to UHB b-values. Two raters R1 and R2 independently assessed DWI and ADC in combination with T2w images. Lesion visibility was best on ultra-high b-value images monoexponentially extrapolated (ME-DWI) from S-DWI and equal on S- and UHB-ADC. The experienced rater was better able to adapt the improved lesion visibility on ME-DWI into the lesion detection task and utilized it for superior predictive performance.

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Qualitative Diagnosis of Complex Ovarian Tumors Using Diffusion Weighted Imaging and Dynamic Contrast-Enhanced Magnetic Resonance Imaging: Correlation with MR Features and Pathology
Shuping Weng1 and Ruqi Fang1

1Radiology, Department of Radiology, Fujian Provincial Maternity and Child Health Hospital, Fuzhou, China

Aims: To evaluate the effectiveness of diffusion weighted imaging and dynamic contrast enhanced magnetic resonance imaging in qualitative diagnosis of complex ovarian tumors.

 Methods: Semi-quantitative parameters of maximal slope of time-signal intensity curve and apparent diffusion coefficient measurements of diffusion-weighted imaging obtained from the tumor solid regions in 65 cases confirmed complex ovarian tumors were done.

Results: A cut-off value of 1.61 × 10-3mm2 /s for ADC was used in differentiating invasive from borderline tumors.Optimal threshold value for maximal slope was 4.58% per second identifying benign and malignant tumors.

Conclusion: Maximal slope value of time-signal intensity curve is the best index in distinguishing malignant from benign ovarian complex tumors,and ADC value of the solid component is the best index in differentiating invasive from borderline ovarian complex tumors.


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Directional Intravoxel Incoherent Motion (IVIM) MR in Rodent Brain
MinJung Jang1, SeokHa Jin1, MungSoo Kang1, SoHyun Han2, and HyungJoon Cho1

1Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Korea, Republic of, 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States

The measurement of white matter flow, which is directional along the neuronal fibers, is challenging due to inherent limitations of low sensitivity and signal-to-noise ratio with arterial spin labeling(ASL)- and dynamic susceptibility contrast(DSC)-MRI acquisitions mainly due to low blood volumes. Recently, flow sensitive intravoxel incoherent motion(IVIM)-diffusion MR has been recognized as being particularly sensitive to directional flows. However, the multi-variable fittings usually suffer from over-fitting and thresholding issues. This study investigated the feasibility of constrained non-negative matrix factorization(cNMF) implementation to IVIM-MR for the automatic segmentation of directional IVIM signals for the purpose of robust detection of directional white matter flow.

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Application of Spinal Cord White Matter Tract Integrity Quantification with Atlas-based Analysis in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder
Masaaki Hori1, Akifumi Hagiwara1,2, Kazumasa Yokoyama3, Kouhei Kamiya2, Issei Fukunaga1, Tomoko Maekawa1,2, Koji Kamagata1, Katsutoshi Murata4, Shohei Fujita1,2, Ryusuke Irie1,2, Christina Andica1, Kanako Kunishima Kumamaru1, Akihiko Wada1, Julien Cohen-Adad5, and Shigeki Aoki1

1Radiology, Juntendo University School of Medicine, Tokyo, Japan, 2Radiology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan, 3Neurology, Juntendo University School of Medicine, Tokyo, Japan, 4Siemens Japan K.K, Tokyo, Japan, 5NeuroPoly Lab, Polytechnique Montreal, Montreal, QC, Canada

We investigated both branches (Da ≤ De,∥ or Da > De,∥) of Kurtosis-based white matter tract integrity to distinguish microstructural changes in the spinal cords of patients with MS and Neuromyelitis Optica. FA and AWF were significant higher and MD was significant lower in spinal cord white matter in MS (P=0.009, 0.024, 0.032, respectively). Di,axial, Di,radial and De,radial of spinal cord white matter in MS were significant lower (P=0.009, 0.024, 0.032, respectively,) in Branch 2(Da > De,∥) in MS. There was no significant difference in Branch 1 ( Da ≤ De,∥) metrics.

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Delineation of thalamic substructures in ultra-high b-value DWI-measurement with reasonable acquisition time
Nils Christoph Nuessle1, Benjamin Bender1, and Uwe Klose1

1Diagnostic and interventional Neuroradiology, University Hospital Tuebingen, Tuebingen, Germany

The purpose of this study was to evaluate the capability of optimized and faster ultra-high b-value DWI in separating and identifying intrathalamic substructures compared to a previously described protocol. 7 subjects underwent MR-imaging, including T1 MPRAGE and two DWI sequences at 0 and 5000  s/mm2. DWI was performed with 64 directions and 5 averages (17:56 min) and with 6 directions and 25 averages (8:23 min). Intrathalamic substructures were semi-automatically delineate 4mm above AC/PC line. Accordance between the original sequence and the new speeded-up measurement was high. Acquisition time was reduced by more than 50 % with comparable results.

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The value of Mean Apparent Propagator (MAP)-MRI in the diagnosis of hippocampal sclerosis
Keran Ma1, Jingliang Cheng1, Xiaonan Zhang1, Ankang Gao1, Chengru Song1, Shaoyu Wang2, Xu Yan2, and Huiting Zhang2

1The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2MR Scientific Marketing, Siemens Healthcare, Shanghai, China, Shanghai, China

This study aimed to explore the value of mean apparent propogation (MAP)-MRI parameters in the diagnosis of hippocampal sclerosis. By comparing the MAP-MRI parameters of hippocampus from both the hippocampal sclerosis patients and the healthy controls, the study found that the MAP-MRI parameters showed high consistency with pathological results, particularly for MSD and QIV. It suggests that MAP-MRI may be used as a diagnostic method with high sensitivity and specificity besides magnetic resonance spectroscopy(MRS) in the future.


Diffusion: Validation

Exhibition Hall
Wednesday 9:15 - 10:15
 Diffusion

3632
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Tunable diffusion kurtosis in lamellar vesicle suspensions toward development of quantitative phantom surrogate of tumor microenvironment
Scott Swanson1, Dariya Malyarenko1, and Thomas Chenevert1

1Radiology, University of Michigan, Ann Arbor, MI, United States

A set of materials based on nanostructured lamellar vesicles with restricted diffusion compartments is constructed to achieve tunable diffusion kurtosis behavior. The observed apparent diffusion (Dapp) and kurtosis (Kapp)  model parameters span the range of values found in vivo. Effect of vesicle population, size, and porosity is studied for estimated diffusion parameters. These nanostructured systems provide an ideal platform for a diffusion kurtosis phantom used to validate quantitative imaging protocols and results.

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Simulation of Intravoxel Incoherent Perfusion Signal using a Realistic Capillary Network of a Mouse Brain
Valerie Phi van1, Franca Schmidt2, Linda Mathez3, Georg Spinner3, Sebastian Kozerke3, and Christian Federau3

1University Hospital Zürich, Zürich, Switzerland, 2Institute of Pharmacology and Toxicology, University of Zurich, Zürich, Switzerland, 3Institute for Biomedical Engineering, ETH and University of Zürich, Zürich, Switzerland

The microscopic origin of the IVIM perfusion signal is not well understood. We simulated blood motion in three realistic microvascular networks obtained by two-photon laser microscopy in mouse brain and computed the effect of this motion on the diffusion-weighted signal MR signal for b-values between 0 and 1000 s/mm2. We found pseudo-diffusion coefficients D* in the range of in vivo measurements. Further, the signal decay was strongly dependent on the specific type of vessel (capillary,arterioles/venules or pial vessels) and on the global vessel diameters of the network.

3634
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Taxon anisotropic phantom delivering human scale parametrically controlled diffusion compartments to advance cross laboratory research and calibration.
Walter Schneider1, Sudhir Pathak1, Yijen Wu1, David Busch1, and John Dzikiy2

1University of Pittsburgh, Pittsburgh, PA, United States, 2Psychology Software Tools, Pittsburgh, PA, United States

Details a novel bi-component polymer Taxon (textile water filled tubes) anisotropic diffusion phantom providing 0.8 microndiameter tubes, packing density of 106 per mm2, water fraction of over 45% matched to human axon histology with parametric control of water compartment (intra/extra axon), size, density, angle dispersion that can be manufactured to supply hundreds of laboratories.  Observed human tissue range FA (0.6-01.0), MD and RD in observed range.  Providing ground truth measurement to advance and calibrate anisotropic diffusion measurement.  Micro-CT and diffusion MRI indicate high water content in agreement with MRI and non MRI measurements.

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Phantoms for Diffusion Simulations: Multi-Objective Differential Evolution for Realistic Numerical (MODERN) Phantoms.
Jonathan Rafael-Patino1, Thomas Yu1, Mariam Andersson2,3, Hans Martin Kjer2,3, Vedrana Andersen Dahl3, Alexandra Pacureanu4, Anders Bjorholm Dahl3, Tim B. Dyrby2,3, and Jean-Philippe Thiran1,5

1Signal Processing Lab (LTS5), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Danish Research Centre for Magnetic Resonance, University Hospital Hvidovre, Hvidovre, Denmark, 3Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark, 4European Synchrotron Radiation Facility, Genoble, France, 5Radiology Department, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland

The following work presents a novel, generally applicable framework (MODERN) which takes, as input, statistics from histology and automatically generates biologically plausible numerical phantoms whose morphological features are optimized to match the input statistics. As a proof of concept, MODERN is used to generate three-dimensional geometrical meshes representing a bundle configuration of axons which can be immediately integrated into Monte Carlo simulations for diffusion MRI acquisitions. The obtained features of the optimised phantoms are shown to match those from the input values. The statistics used were obtained from axonal segmentations from synchrotron imaging.

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Axon-mimicking hydrophilic fibre phantoms for diffusion MRI
Fenglei Zhou1,2, Amy McDowell3, Kiran Seunarine3, Matt G. Hall3,4, Damien J. McHugh1, Zhanxiong Li5, Chris Clark3, Penny L Hubbard Cristinacce1, and Geoff J. M. Parker1,6

1Quantitative Biomedical Imaging Laboratory, The University of Manchester, Manchester, United Kingdom, 2School of Materials, The University of Manchester, Manchester, United Kingdom, 3Developmental Imaging and Biophysics, UCL Great Ormond Street Institute of Child Health, London, United Kingdom, 4National Physical Laboratory, Teddington, London, United Kingdom, 5College of Textile and Clothing Engineering, Soochow University, Suzhou, China, 6Bioxydyn Limited, Manchester, United Kingdom

We report the development of an axon-mimicking phantom composed of hydrophilic hollow microfibres, and evaluate its potential for validating clinical diffusion MRI. Microfibers were fabricated by the co-electrospinning (co-ES) of polycaprolactone (PCL)-polysiloxane-based surfactant (PSi) mixture as shell and polyethylene oxide (PEO) as core, and characterized by scanning electron microscopy (SEM). Three material samples were constructed and included in the phantom within a water bath. SEM images reveal that PCL-PSi fibres in the samples were uniaxially aligned and hollow, with a similar distribution of pore sizes to axons in vivo. MR measurement shows similar anisotropic diffusion behaviour in each sample.

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Multisite evaluation of repeatability and stability for a novel quantitative diffusion kurtosis phantom
Dariya Malyarenko1, Scott D Swanson1, Amaresha S Konar2, Eve LoCastro2, Ramesh Paudyal2, Michael Z Liu3, Sachin R Jambawalikar3, Lawrence H Schwartz3, Amita Shukla-Dave4, and Thomas L Chenevert1

1Radiology, University of Michigan Health System, Ann Arbor, MI, United States, 2Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 3Columbia University Irving Medical Center, New York, NY, United States, 4Medical Physics and Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States

Multi-center clinical trials utilizing quantitative diffusion kurtosis imaging (DKI) protocols require accurate, precise, and stable phantoms for validation of derived imaging metrics.  This study examines the precision and reproducibility of isotropic (i)DKI parameters obtained from a phantom based on nanostructured vesicles that restrict diffusion and mimic tissue cellularity.  Ten test-retest iDKI studies were performed on four scanners at three imaging centers over a six-month period. The tested prototype phantoms exhibited physiologically-relevant and highly-repeatable apparent diffusion and kurtosis parameters. Achieved precision was sufficient to characterize thermal and temporal stability trends to guide robust quantitative iDKI phantom production.

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Comparison of dMRI Models for Skeletal Muscle Microstructure Estimation with Numerical Simulations and Porcine Phantom
Noel M. Naughton1, Nicolas R. Gallo2, Aaron T. Anderson3,4, and John J. Georgiadis2,5

1Mechanical Science and Engineering, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 2Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, 3Beckman Institute for Advanced Science and Technology, Univeristy of Illinois at Urbana Champaign, Urbana, IL, United States, 4Radiology, Carle Foundation Hospital, Urbana, IL, United States, 5Mechanical Science and Engineering, University of Illinois at Urbana Champaign, Urbana, IL, United States

Four models used to estimate skeletal muscle microstructure from dMRI signal are applied to a ex-vivo porcine phantom and provide physiologically reasonable parameter estimates. These models are then compared to numerical simulations of dMRI over a simplified repeating elemental volume. When the estimated parameters are compared to the true underlying parameters of the numerical model, the estimated parameters are found to be substantially inaccurate, motivating the need for more sophisticated models of dMRI in muscle.  

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Towards a more realistic and flexible white matter numerical phantom generator for diffusion MRI simulation
Ross Callaghan1, Noam Shemesh2, Daniel Alexander1, Hui Zhang1, and Marco Palombo1

1Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom, 2Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal

We present a novel method for the generation of realistic white matter numerical phantoms with controllable morphology, and more realistic orientation-dispersion and packing-density. A shift of paradigm is proposed: rather than ‘packing fibres’, our algorithm ‘grows fibres’ contextually and efficiently, avoiding intersection between fibres. The potential of the method is demonstrated by reaching the highest orientation-dispersion and packing-density ever. The flexibility of the method is demonstrated with simulations of diffusion-weighted MR signal in three example substrates with differing orientation-dispersions, packing-densities and permeabilities. A proof-of-concept application is presented to investigate the impacts of undulation and beading on the intra-axonal axial diffusivity.

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Quantitative Comparison of 6 different Diffusion Weighted Imaging Approaches using NIST Diffusion Phantom
Sampada Bhave1, S. Sivaram Kaushik2, Robert D Peters2, and Kevin M Koch1

1Medical College of Wisconsin, Milwaukee, WI, United States, 2GE Healthcare, Waukesha, WI, United States

The application of diffusion weighted imaging (DWI) is rapidly increasing in musculoskeletal system. DWI is useful in imaging diverse range of musculoskeletal pathologies like soft-tissue tumors, bone lesions, vertebral fractures pre and post treatment follow up. In this work, our goal is to quantitatively compare the accuracy of ADC estimation of EPI, and PROPELLER based techniques. We also optimize the imaging parameters for PROPELLER and MSI-PROPELLER techniques and provide a correction method to improve the accuracy of ADC estimation.

3641
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Validation and Estimation of crossing angles of fiber bundle with different density using hollow textile-based phantom
Sudhir Kumar Pathak1, Vinod Jangir Kumar2, and Walter Schneider 3,4

1Learning Research and Development Center, University of Pittsburgh, Pittsburgh, PA, United States, 2Biological Cybernetics, Max Planck Institute, Tuebingen, Germany, 3Psychology, Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States, 4Neurosurgery, Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States

A textile-based hollow fiber (taxon) MRI phantom (TABIP) is used to assess the ability of diffusion MR imaging (dMRI) to accurately estimate taxon crossing angles.  A parametric pattern of known taxon crossings and taxon bundle sizes was manufactured in the TABIP phantom, it was scanned on a 3T scanner and data was reconstructed with a constrained spherical deconvolution algorithm.  21 repeated scans were collected to enhance SNR. Taxon crossing angles were estimated, and it is shown that crossing angles of 45° and higher can be accurately recovered and that angle measurement reliability decreases with bundle size.

3642
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Novel Atlas of Fiber Directions Built From Ex Vivo DT images of Porcine Hearts
Mia Mojica1, Mihaela Pop2, Maxime Sermesant3, and Mehran Ebrahimi1

1University of Ontario Institute of Technology, Oshawa, ON, Canada, 2Sunnybrook Research Institute, Toronto, ON, Canada, 3INRIA Sophia Antipolis, Sophia Antipolis, France

In this study we successfully created the first high-resolution cardiac Diffusion Tensor (DT) imaging-based fiber atlas from porcine hearts. Furthermore, we laid the foundation of a framework for building a statistical cardiac atlas by computing an average cardiac geometry from a small database (N=8) of explanted porcine hearts without the need for selecting landmarks, transforming the diffusion tensors of subjects, and obtaining the associated average DT field and fiber architecture. The fiber atlas can be used for personalized electro-mechanical simulations of cardiac function (in anisotropic models when DT data is not available), and aid in diagnosis or therapy guidance procedures.

3643
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OGSE diffusion weighted imaging of epidermoid cysts: 3D Monte Carlo simulation
Saori Koshino1,2, Akiyuki Sakakibara3, Christina Andica2, Akifumi Hagiwara1,2, Masaaki Hori2, Osamu Abe1, and Shigeki Aoki2

1Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan, 2Department of Radiology, Juntendo University Graduate School of Medicine, Tokyo, Japan, 3LPixel Inc., Tokyo, Japan

Diffusion weighted imaging with shorter diffusion time using oscillating gradient spin echo (OGSE) may reveal microstructural features among brain disorders. Here we observed DTI eigenvalues in four patients with epidermoid cysts. The values measured by OGSE were higher than those measured by pulsed gradient spin echo (PGSE; used in conventional MRI), indicating restricted diffusion due to spatial restriction and/or viscosity. The results of our Monte Carlo simulation based on the pathological feature of epidermoid cysts suggest that spatial restriction of multiple ellipsoids formed by keratin filaments as well as viscosity and water exchange should influence the extent of restricted diffusion.

3644
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Studying the effect of membrane permeability with a GPU-based Bloch–Torrey simulator
Jan N Rose1, Lukasz Sliwinski1, Sonia Nielles-Vallespin2,3, Andrew D Scott2,3,4, and Denis J Doorly1

1Department of Aeronautics, Imperial College London, London, United Kingdom, 2Cardiovascular Magnetic Resonance Unit, The Royal Brompton Hospital, London, United Kingdom, 3National Heart and Lung Institute, Imperial College London, London, United Kingdom, 4Data Science Institute, Imperial College London, London, United Kingdom

To better understand diffusion MRI in biological tissues, numerical simulations are commonly used to model the MR signal. Realistic simulation substrates built directly from histology images help to reduce the model error, but intrinsic parameters other than the microstructure have an effect too. In this study, we investigate the relationship between diffusion tensor fractional anisotropy and membrane permeability. Using a GPU-accelerated Bloch–Torrey solver, we observe a significant difference from the impermeable case for long diffusion times on the order of 1s.

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Comparison of Cylindrical and Spherical Geometric Models to Infer Cell Sizes in a Celery Sample
Sheryl L Herrera1,2, Morgan E Mercredi3, Henri R Sanness Salmon1, Guneet Uppal1, Domenico L Di Curzio4, and Melanie Martin1

1Physics, University of Winnipeg, Winnipeg, MB, Canada, 2Cubresa, Inc., Winnipeg, MB, Canada, 3Physics and Astronomy, University of Manitoba, Winnipeg, MB, Canada, 4Biology, University of Winnipeg, Winnipeg, MB, Canada

Temporal diffusion spectroscopy (TDS) can be used to infer sizes of cells in samples. It relies on a geometric model to relate the MRI signal to the cell sizes. Celery collenchyma tissue and vascular bundles have long cells while parenchyma cells are rounder. We compared a cylindrical and spherical geometric model in temporal diffusion spectroscopy to determine how important the geometrical model was for celery. The inferred diameters of cells in celery (14±6µm to 20±12µm) were not statistically different when using the two different geometric models. This is the first step toward understanding the importance of geometric models for TDS.

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Kärger Model Difficulties for In Vivo DWI
Catherine L Lian1,2, Brendan Moloney2, Eric M Baker2, Greg Wilson3, Erin W Gilbert4, Thomas M Barbara2, Charles S Springer2, and Xin Li2

1Westview High School, Portland, OR, United States, 2Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 3Home, Mill Creek, WA, United States, 4Surgery, Oregon Health & Science University, Portland, OR, United States

Although it is well known that diffusion-weighted imaging (DWI) is sensitive to in vivo trans-membrane water-exchange, quantitative interpretation of the diffusion b-space decay remains difficult. Using random-walk simulated DWI data, this study investigates the feasibility and reliability in studying the water exchange effects with a multi-exponential fitting approach on DWI data. 

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Non-destructive measurement and prediction of soluble solids of fruits using diffusion-weighted magnetic resonance imaging
Xinpei Wang1, Jichang Zhang1, Zhen Nan1, Pengfei Xu1, Richard Bowtell2, and Chengbo Wang1

1Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo, China, 2Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, The University of Nottingham, Nottingham, United Kingdom

Diffusion-weighted magnetic resonance imaging (DW-MRI) was used to measure and predict total soluble solids (TSS, unit: °Brix) of fruits noninvasively. The results demonstrated that mean apparent diffusion coefficient (ADC) in fruits was strongly correlated with TSS of fruit juice (R ≥ 0.92 and p ≤ 1.51E-4). DW-MRI shows great potential for future commercial implementation of fruit quality evaluation.

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Diffusion Time Dependence of Diffusion Tensor Parameters in the Evaluation of Meningioma Subtype: a Preliminary Study
Tomoko Maekawa1,2, Masaaki Hori1, Katsutoshi Murata3, Christina Andica1, Yutaka Ikenouchi1, Shohei Fujita1, Ryusuke Irie1,2, Akifumi Hagiwara1,2, Kamiya Kouhei1,2, Koji Kamagata1, Akihiko Wada1, and Shigeki Aoki1

1Radiology, Juntendo University Hospital, Tokyo, Japan, 2Radiology, The University of Tokyo Hospital, Tokyo, Japan, 3Siemens Healthcare Japan KK, Tokyo, Japan

We investigated the DTI eigenvalues and MD of five types of meningioma acquired with a shorter diffusion time using an OGSE sequence. Eleven meningiomas that consisted of 4 meningothelial meningiomas, 2 fibrous meningiomas, 2 transitional meningiomas, 1 psammomatous meningioma, and 2 atypical meningiomas were analyzed. Our results showed that the psammomatous and atypical meningiomas had a relatively strong diffusion time-dependence of diffusion tensor metrics. The use of shorter diffusion time with DTI provide additional information about the microstructure of each meningioma subtypes.

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Whole-Tumor Histogram Analysis of Monoexponential and Advanced Diffusion-weighted Imaging for Sinonasal Malignant Tumors: Correlations with Histopathologic Features
Zebin Xiao1, Zuohua Tang2, Jing Zhang3, Guang Yang3, Wenjiao Zeng4, Jianfeng Luo5, Rong Wang2, Linying Guo2, and Zhongshuai Zhang6

1Eye & ENT Hospital of Fudan University, Shanghai, China, 2Radiology, Eye & ENT Hospital of Fudan University, Shanghai, China, 3Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, 4Pathology, School of Basic Medical Sciences, Fudan University, Shanghai, China, 5Biostatistics, School of Public Health, Fudan University, Shanghai, China, 6MR Scientific Marketing, Siemens Healthcare, Shanghai, China

This is the first study with a large sample size to systematically investigate the correlation of monoexponential diffusion-weighted imaging (DWI) and advanced DWI (intravoxel incoherent motion [IVIM] and diffusion kurtosis imaging [DKI]) parameters with histopathologic features of sinonasal malignant tumors using whole-tumor histogram analysis, which could improve the interpretation of DWI findings and promote the use of these diffusion methods in clinical practice. In comparison with monoexponential DWI and biexponential DWI (IVIM), histogram metrics derived from DKI may better reflect the microstructure of sinonasal malignant tumors, including the cellular, stromal and nuclear fractions.

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Examining Links Between Free Water and a TSPO-PET Marker of Neuroinflammation
Benjamin E. Reid1, Maria Di Biase1, Martin G. Pomper2,3, Martha E. Shenton1,4,5, Yong Du3, Jennifer M. Coughlin2,3, and Ofer Pasternak1,4

1Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Boston, MA, United States, 2Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, United States, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, United States, 4Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States, 5Research and Development, VA Boston Healthcare System, Boston, MA, United States

Free-water (FW) is a diffusion MRI marker of freely diffusing water in the extracellular space, which is expected to increase in the presence of neuroinflammation. Here, we test associations between FW and positron emission tomography (PET) imaging of the translocator protein (TSPO), which is a putative neuroinflammatory marker. We show that increased FW relates to higher TSPO binding in the hippocampi of healthy controls, but not of individuals with sports-related, repetitive traumatic brain injury. Thus, while FW relates to TSPO under healthy conditions, pathological variance in TSPO may complicate associations between FW and TSPO-indexed neuroinflammation.

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A Novel Metric Shows the Robustness of the Graph Communities to Brain-Tractography False-Positives.
Juan Luis Villarreal-Haro1, Alonso Ramirez-Manzanares1, and Juan Antonio Pichardo-Corpus2

1Computer Science, Centro de Investigación en Matemáticas A.C., Guanajuato, Mexico, 2CONACYT-CentroGeo-CentroMet, Queretaro, Mexico

We study the impact of the brain tractography false positives in the brain connectivity graphs. The representative input database for the analysis is the set of tractograms from the participants on the ISMRM-2015 Tractography Challenge. We propose 2 novel metrics to rank the quality of a tractogram when it is compared with a known ground truth.  The results of this study indicate that the the estimation of graph communities is robust to high levels of overestimation in the connectivity.

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The multi-play of diffusion tensor imaging and immunohistochemistry to unveil the longitudinal microstructural brain alterations in a closed head brain injury model.
Abdalla Z Mohamed1, Lyndsey E. Collins-Praino2, Frances Corrigan3, and Fatima Nasrallah1

1Queensland Brain institute, Brisbane, Australia, 2Adelaide Medical School, University of Adelaide, Adelaide, Australia, 3School of Health Sciences, University of South Australia, Adelaide, Australia

Traumatic brain injury (TBI) is a disease burden worldwide and it is associated with axonal injury and neuroinflammation. Investigating the underlying mechanisms and the progression in the acute and sub-acute stages following TBI non-invasively would aid for early diagnosis and intervention. In this study, we used diffusion tensor imaging (DTI) to investigate the microstructural changes following TBI. Furthermore, we used immunohistochemistry to investigate the axonal injury and microglial activity following TBI. Using DTI, we detected persistent microglial activity associated with TBI which might suggest a possible use of DTI for reflecting on the microstructural changes associated with TBI in humans.

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How reproducible are the results of probabilistic white matter tract estimation?
Irène Brumer1,2, Enrico De Vita1, Jonathan Ashmore2,3, Jozef Jarosz2, and Marco Borri2

1Department of Biomedical Egineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Department of Neuroradiology, King's College Hospital, London, United Kingdom, 3Department of Medical Physics and Bioengineering, NHS Highland, Inverness, United Kingdom

Diffusion tractography and fMRI data is valuable for pre-surgical planning, but its analysis involves a number of user-dependent decisions. In particular the choice of activation threshold in fMRI maps and the definition of seed region in tractography may impact the results. This work evaluates both the intrinsic variability of probabilistic white matter tract estimation and the inter-user reproducibility of tractography analysis. The former was estimated from repeated identical processing, while for the latter tracts obtained by different users were compared. Achieving a good inter-user reproducibility (up to 85%) is possible, considering that the intrinsic reproducibility ranged between 72% and 89%. 

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Consistency and Reproducibility of Probabilistic Tractography
Jian J. Lin1, Mark J. Lowe1, Robert J. Fox2, and Ken Sakaie1

1Imaging Institute, The Cleveland Clinic, Cleveland, OH, United States, 2Neurological Institute, The Cleveland Clinic, Cleveland, OH, United States

Deciding from among the many available tractography algorithms can be challenging. We demonstrate that track-based measures can be compared using standard statistical approaches to compare the performance of two probablistic tractography algoirthms to determine the conditions under which one algorithm can replace another.

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Validation of Diffusion Imaging Measures in Gray Matter using Histology from macaque monkey
Madhura Baxi1,2, Suheyla Cetin Karayumak2, Doug Richardson3, George Papadimitriou4, Sarina Karmacharya2, Nikos Makris2, Andre van der Kouwe5, Bruce Jenkins5, Thomas Witzel5, Tara Moore6, Douglas Rosene6, Marek Kubicki2, and Yogesh Rathi2

1Graduate Program for Neuroscience, Boston University, Boston, MA, United States, 2Psychiatry NeuroImaging Lab, HMS, BWH, Boston, MA, United States, 3Harvard Center for Biological Imaging, Harvard University, Cambridge, MA, United States, 4Center for Morphometric Analysis, Massachusetts General Hospital, Charlestown, MA, United States, 5Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 6Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States

This study is the first attempt towards histological validation of diffusion imaging measure of Trace in the gray matter of macaque monkey. Heterogeneity of Trace (hTrace) computed for one monkey in 7 cytoarchitectonically different regions was compared with the variance in intracellular volume fraction for the same regions computed using digitized histological sections, stained for all cell bodies. hTrace was found to be significantly correlated with the variance in intracellular volume fraction. This shows that the diffusion measure of hTrace is sensitive to the underlying gray matter cytoarchitecture such as the cell size and cell packing density.

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Free water mapping in diffusion MRI: How do two common approaches compare?
Jordan A. Chad1,2, Ofer Pasternak3, and J. Jean Chen1,2

1Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States

Free water eliminated diffusion tensor imaging (fwDTI) and neurite orientation dispersion and density imaging (NODDI) are two increasingly established techniques that measure free water (FW) in diffusion MRI. Yet, despite the utility of each approach, their corresponding FW estimates have yet to be compared. In this work, we find that FW measurements near cerebrospinal fluid are highly similar between the two approaches, but within tissue, NODDI tends to compute slightly higher FW values in the white matter and lower FW values in gray matter than fwDTI. Potential sources of this discrepancy are discussed.


Value of MRI

Exhibition Hall
Wednesday 9:15 - 10:15
 MR Value

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Value of patent foramen ovale in grey matter and white matter lesions of migraine: A comparative study
yitong bian1, jian yang1, zhijie jian1, junjun li1, zhe liu1, and guogang luo2

1Department of Diagnostic Radiology, First Affiliated Hospital of Xi’an Jiaotong University, xi'an, China, 2Department of Neurology, First Affiliated Hospital of Xi’an Jiaotong University, xi'an, China

Migraine is a complicated neurological disability disease and still not been clarified. PFO may be a subset to cause migraine. Therefore, this study aims to analysis the value of PFO in grey matter and white matter lesions of migraine. We found that the changes mainly in frontal cortex, precentral gyrus regions of pain modulating area between patients with PFO and without PFO in migraine. However, out results do not support the relationship between PFO and white matter lesions. This findings may provide a new insight for clinical treat strategy. 

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A New Nodal Staging System for Nasopharyngeal Carcinoma Based on the Quantitation of Metastatic Lymph Nodes
Haojiang Li1, Chunyan Cui1, Fei Xie1, Jian Zhou1, Annan Dong1, Huali Ma1, and Lizhi Liu1

1radiology, Sun Yat-sen University Cancer Center, Guangzhou, China

We aimed to investigate whether the number of metastatic lymph nodes (LNs) is an independent prognostic factor for progression-free survival (PFS) in nasopharyngeal carcinoma (NPC) and to establish a new N staging system based on the number of positive LNs on magnetic resonance imaging. In 792 NPC patients, we found that the number of metastatic LNs was the only independent prognostic factor for PFS following multivariate analysis. We categorized the number of metastatic LNs into 4 groups to create a new N staging system which was more effective than the American Joint Committee on Cancer staging system for predicting PFS. 

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Accuracy of Synthetic MAgnetic Resonance image Compilation (MAGiC) neural scan
Chia-Wei Li1, Ai-Ling Hsu1, Chien-Yuan Eddy Lin2, Charng-Chyi Shieh2, and Wing P. Chan1,3

1Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan, 2GE Healthcare, Taipei, Taiwan, 3Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan

This study aimed to verify the accuracy of quantitative T1 and T2 estimation generated from a synthetic MR imaging method, MAGiC by comparing these results with conventional scanning on a homemade phantom with 9 concentration of aqueous CuSO4, and our result showed that the quantitative estimations were inaccurate in the CSF regions. In addition, the MAGiC synthetic image contrast was evaluated in both healthy volunteers and stroke patients. Agreed with the quantitative estimations, the CSF regions caused the apparent contrast differences.

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Comparing the Quantitative T1 and T2 Mapping Acquired by Magnetic Resonance image Compilation (MAGiC) and MR Fingerprinting (MRF)
Chia-Wei Li1, Ai-Ling Hsu1, Chien-Yuan Lin2, Charng-Chyi Shieh2, Jianxun Qu3, Guido Buonincontri4,5, and Wing P. Chan1,6

1Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan, 2GE Healthcare, Taipei, Taiwan, 3GE Healthcare MR Research China, Beijing, China, 4IMAGO7 Foundation, Pisa, Italy, 5National Institute for Nuclear Physics, Pisa, Italy, 6Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan

Quantifying tissue T1 and T2 provides valuable biomarker for characterizing various tissue pathologies yet limits by its long scan time and consequently hampered their clinical practice. Magnetic resonance image compilation (MAGiC) and Magnetic resonance fingerprinting (MRF) are novel imaging techniques that simultaneously provide quantitative maps of tissue relaxation times at one acquisition. We compared the quantitative values in various brain tissue using the MAGiC and MRF in healthy volunteers. In quantifying T1 between two techniques, no significant difference was found in white matter and gray matter, but difference was observed in cerebrospinal fluid. On the contrary, T2 value showed significant difference.

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Clinical Implementation of Fast Markerless Motion Correction in K-Space of Structural 3D MR-Images of the Brain
Jakob Slipsager1,2,3, Stefan Glimberg2, Daniel Gallichan4, Liselotte Højgaard3, Rasmus Paulsen1, and Oline Olesen1,2

1DTU Compute, Technical University of Denmark, Lyngby, Denmark, 2Tracinnovations, Ballerup, Denmark, 3Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Copenhagen, Denmark, 4CUBRIC School of Engineering, Cardiff University, Cardiff, United Kingdom

This work demonstrates retrospective motion correction using a markerless motion tracker to accommodate the needs in the clinical workflow. Motion degradation in neurological MRI imaging is a major concern and causes increased study time and cost due to repeated scans and the need for sedation or anesthesia. With retrospective motion correction of raw k-space data, both the corrected and non-corrected images can be reconstructed and presented for the radiologists within a few minutes. The external markerless motion tracker is sequence independent meaning that retrospective motion correction can be applied to clinical examination without sequence modification or added scan time.

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Early evaluation of radiation-induced parotid damage in patients with nasopharyngeal carcinoma by T2 mapping and mDIXON Quant imaging: initial findings
zhengyang zhou1, Jian He1, and Weibo Chen2

1Radiology, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China, 2Philips Healthcare, Shanghai, China

Forty-one patients with NPC underwent T2 mapping and mDIXON Quant imaging for parotid glands before RT, mid-RT, and post-RT. From pre-RT to mid-RT, parotid T2 and FF values increased significantly. From mid-RT to post-RT, parotid T2 value continuously increased, but parotid FF value decreased significantly. Change rate of parotid T2 value significantly correlated with parotid atrophy rate from pre-RT to post-RT. Parotid T2 value and FF value negatively correlated with parotid volume, while parotid T2 value positively correlated with MR scan time point significantly. T2 mapping and mDIXON Quant imaging is useful for noninvasive evaluation of radiation-induced parotid damage.

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Functional stability of clinical research neurological scanners
Antonio Napolitano1, Martina Lucignani1, Francesca Bottino1, Anna Nigri2, Domenico Aquino2, Fulvia Palesi3, Maria Grazia Bruzzone2, Michela Tosetti4,5, Claudia A. M. Gandini Wheeler-Kingshott6,7,8, and the Italian IRCCS advanced neuroimaging network9

1Medical Physics Department, Bambino Gesù Children's Hospital, Rome, Italy, 2Neuroradiology Department, Carlo Besta Neurological Institute, Milan, Italy, 3Brain MRI 3T Center, Mondino National Neurological Institute, Pavia, Italy, 4IRCCS Stella Maris Foundation, Pisa, Italy, 5Imago7 Foundation, Pisa, Italy, 6Brain MRI 3T Research Center, Mondino National Neurological Institute, Pavia, Italy, 7Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy, 8Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom, 9Advanced Neuroimaging Network of Italian Research Neurological Institutes (IRCCS), Italy, Italy

A multicenter network of Italian Neurological Research Hospital was recently started. Its first aim was to establish quality assessment protocols for future quantitative imaging studies. In this context, we report the outcome of the first 6 months of data collection using a dedicated phantom and processing pipeline. Scanner performance was assessed in terms of several stability indicators, grouped by manufacturer. The preliminary results represent the initial step towards a large-scale scanner stability assessment in clinical settings. We expected to gather regular data from all the sites in order to broaden data analysis and assess the multi-site temporal stability.

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Single-breath-hold whole-heart-coverage accelerated 3D-cine cardiac MRI
El-Sayed H Ibrahim1 and Kevin Koch1

1Medical College of Wisconsin, Milwaukee, WI, United States

Conventional cine imaging consumes a large part of scan time due to the need to acquire a stack of short-axis and long-axis slices. In this study, we provide preliminary results about the feasibility of a single-breath-hold whole-heart-coverage accelerated 3D-cine acquisition in a fraction of this time using recent developments in acquisition and reconstruction techniques. The results shows significantly reduction of scan time by more than 90%. Despite encountered reduction in resolutions, SNR and CNR, sufficient image quality was maintained such that the resulting clinical measurements were not significantly different from those obtained using conventional cine acquisition.

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Hypovascular nodules detected on gadoxetic acid-enhanced MR imaging: Risk factors and appropriate treatments for hypervascular transformation
E Tuya1, Ou Yanghan2, and Xie Lizhi3

1Department of Radiology, National Cancer Center/National Clinical Research Center for Cancer/ Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China., Beijing, China, 2Department of Radiology, National Cancer Center/National Clinical Research Center for Cancer/ Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, Beijing, China, 3GE Healthcare, MR Research China, Beijing, China, Beijing, China

Hypovascular hypointense nodules detected in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI have significant potential to transform into hypervascular hepatocellular carcinoma (HCC). This study aims to assess the risk factors for hypervascular transformation and to enable guiding the clinical treatment properly.

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Evaluation the functional of parotid glands in diabetic patients: diffusion-weighted echo-planar MRI before and after stimulation
Xuemei Wang1, Mingjia Niu1, Lanxiang Liu1, Yuan Fang1, Tao Zheng1, Juan Du2, Qinglei Shi3, Shuang Wu1, and Jinglong Li1

1Qinhuangdao Municipal No. 1 Hospital, Qinhuangdao, China, 2Graduate School of Hebei Medical University, Shijiazhuang, China, 3MR Scientific Marketing, Siemens Healthcare, Beijing, China

   Recent studies have reported that lipid infiltration (LIPG) may be one of the mechanisms of salivary secretion decrease in diabetic patients. In this study, we compared the difference of ADCs between normal and patients before and after stimulation. It demonstrated that diffusion-weighted echo-planar MR imaging allows non-invasive quantification of functional changes in the parotid glands and the feasibility in reflecting the degree of fat deposition in parotid gland caused by parotid dysfunction.

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Improving Patient Comfort by Shortening MR Scan Duration with the Help of Compressed SENSE
Karthick Raj Rajendran1, Dr. Rakesh. K. Gupta2, and Rupsa Bhattacharjee3

1Philips Health Systems, Philips India Limited, Chennai, India, 2Deaprtment of Radiology, Fortis Memorial Research Institute, Gurugram, India, 3Philips Health Systems, Philips India Limited, Gurugram, India

Compressed SENSE i.e parallel imaging combined with Compressed Sensing, plays a vital role in reducing the overall imaging time without compromising the image quality. Objective of the study is to analyze the impact of using Compressed SENSE to improve the patient comfort by reducing the scan time. This is achieved by implementing Compressed SENSE in T1, T2, PD Weighted TSE, T1 & T2 FFE based sequences in 2D & 3D mode in routine MR Examinations.

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Comprehensive comparison of MR image quality between intratympanic and intravenous gadolinium injection using 3D real IR sequences
Yang Li1, Yan Sha2, Feng Wang3, Ping Lu4, Lan Xi Liu2, Ru Ya Sheng2, Shuai Zhong Zhang5, and Xiao Meng Liu 6

1Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai, China, 2Eye & ENT Hospital of Fudan University, Shanghai, China, 3Weifang People's Hospital, Weifang, China, 4Suzhou Municipal Hospital, Suzhou, China, 5Scientific Marketing, Siemens Healthcare Ltd, Shanghai, China, 6Scientific Marketing, Siemens Healthcare Ltd., Shanghai, China

Both intratympanic (IT-method) and intravenous (IV-method) administration of gadodiamide are used to detect endolymphatic hydrops. The purpose of our study was to comprehensively compare the image quality of the two methods. By qualitative and quantitative comparison, the IV-method can be used as an alternative to the IT-method in future clinical applications.

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MRI prediction of Slipped Capital Femoral Epiphysis in children
Yue Gao1, Qiang Liu1, Qi Li2, Jiazheng Wang3,4, and Shinong Pan1

1Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China, 2Department of Radiology, Liaoning Electric Power Center Hospital, Shenyang, China, 3Philips Healthcare, Beijing, China, 4Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom

We compared the MRI images of peripheral skeletal muscle atrophy and steatosis between heathy children and children with Slipped Capital Femoral Epiphysis (SCFE). Statistical analysis revealed the correlation between the two pathological changes in MRI images and the incidence of SCFE,and get the threshold value of two indicators leading to the onset of SCFE,which holds potential for the guidance on clinical diagnosis and therapy plan for SCFE.

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Enhanced Value and Diagnostic Utility in Musculoskeletal MRI Using ZTE
Ryan E. Breighner1, Erin C. Argentieri1, Alissa J. Burge1, Matthew F. Koff1, and Hollis G. Potter1

1Radiology and Imaging, Hospital for Special Surgery, New York, NY, United States

Zero Echo Time (ZTE) MRI affords CT-like positive contrast visualization of bone This study highlights instances in which ZTE imaging proved clinically useful as an adjunct to standard-of-care MRI in diagnosis and treatment of musculoskeletal injuries. Cases are presented in which patient circumstances (pregnancy, age, prior imaging, etc.) coupled with the underlying pathology resulted in added diagnostic, safety, monetary, and/or temporal value for the patient or care team. This study coupled with our prior work indicates that ZTE imaging can provide a suitable alternative to CT and, in certain circumstances may in fact, be preferable.  

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The changes of R2’ in quantitative evaluation of acute renal injury: Preliminary animal study
Weizheng Gao1, Chengyan Wang2, Hanjing Kong1, Min Yang3, Xiaodong Zhang3, Jue Zhang1, and Xiaoying Wang3

1Peking University, Beijing, China, 2Shanghai Jiao Tong University, Shanghai, China, 3Peking University First Hospital, Beijing, China

As a recently proposed novel pulse sequence, the pulse-shifting multi-echo asymmetric spin echo (psMASE) can isolate R2’ in real time. Combined with gas challenge, it can be used to evaluate acute renal injury (AKI) quantitatively. In this study, we further investigated the feasibility of the change of R2' value (dR2’) in distinguishing different severities of AKI using this sequence. Results suggested that there was significant difference between the different severities of AKI and dR2’, which indicating that the dR2' value can serve as a potential quantitative indicator for acute renal injury evaluation.

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A test-retest multi-site reproducibility of neurovascular 4D flow MRI
baohong wen1,2, bing wu3, yang fan3, and jingliang cheng2

1MR, the First Affiliated Hospital of Zhengzhou University, zhengzhou, China, 2the First Affiliated Hospital of Zhengzhou University, zhengzhou, China, 3GE Healthcare, beijing, China

4D flow shows great potential in neurovascular disorders such as stenosis, atherosclerotic disease, aneurysms, and vascular malformations; its widespread application in neurovascular system requires evidence of good test-retest multi-site reproducibility. This study would like to assess the multi-center reproducibility, test-retest variability and inter-observer dependence of 4D flow MRI in neurovascular system.

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3D CUBE MRI of facial nerve lesions in temporal bone: a preliminary study
Hui Zhao1, Li Xin Sun2, Weiqiang Dou3, Jin Ye Li1, Na Hu2, and Ruo Zhen Gong2

1Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China, 2Department of Radiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China, 3GE Healthcare MR Research, Beijing, China

This study mainly investigated the feasibility of three-dimensional (3D) CUBE MRI for high resolution facial nerve imaging in patients with peripheral paralysis. We thus systematically measured the corresponding patients with three different syndromes using 3D fat suppressed CUBE technique. While significant image enhancement between the affected and unaffected sides was almost shown in all segments for the patients, different effects were found in mastoid and internal auditory canalicular regions,We thus can demonstrate the feasibility of 3D CUBE MRI in the diagnosis of patients with facial paralysis relevant diseases.  

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The prognostic value of detailed MRI reports in predicting the progress-free survival of patients with nasopharyngeal carcinoma
Fei Xie1, Haojiang Li1, and Lizhi Liu1

1Department of Radiology, Sun Yat-sen University Cancer Center, Guangzhou, China

To evaluate the prognostic value of detailed MRI reports for progress-free survivals (PFS) of patients with Nasopharyngeal Carcinoma (NPC) who underwent intensity modulated radiation therapy (IMRT), we used Cox regression to analyze all the variables of detailed MRI reports and to build a new nomogram for PFS. Our results demonstrated that the new nomogram was more efficient than the American Joint Committee on Cancer (AJCC) 8th staging system. These results indicated that detailed MRI reports could play a more important role in predicting PFS, and some significant factors may be added to improve the current staging system.

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3D T1-weighted Images with Scan Time of Less than 2 Minutes by Using Wave-CAIPI
Yasutaka Fushimi1, Tomohisa Okada2, Sonoko Oshima1, Yusuke Yokota1, Hikaru Fukutomi1, Gosuke Okubo1, Satoshi Nakajima1, Akira Yamamoto3, Wei Liu4, Sinyeob Ahn5, Thomas Beck6, and Kaori Togashi1

1Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan, 2Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan, 3Integrated Clinical Education Center, Kyoto University Hospital, Kyoto, Japan, 4Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 5Siemens Healthineers, San Francisco, CA, United States, 6Siemens Healthineers, Erlangen, Germany

A preliminary imaging study for MPRAGE with Wave-CAIPI has been introduced at the clinical MR scanner. MPRAGE with Wave-CAIPI 3×3 shows relatively better contrast despite its short scan time. Less imaging noise and segmentation error was found in MPRAGE with Wave-CAIPI 3×3. MPRAGE with GRAPPA 3×3 showed prominent imaging noise and segmentation errors, however, MPRAGE with CAIPI 3×3 showed few segmentation errors and almost equivalent to Wave-CAIPI 3×3.

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Decreased Relative Cerebral Blood Flow In Unmedicated Heroin Use Disorders
Wenhan Yang1, Ru Yang1, Jing Luo1, Lei He1, Jun Liu1, and Jun Zhang2

1Department of Radiology, Second Xiangya Hospital of Central South University, Changsha, China, 2Department, Hunan Judicial Police Academy, Changsha, China

Sixty-eight patients with heroin use disorders(HUD) and forty-seven matched healthy controls underwent a high resolution T1 and whole-brain pulse arterial spin labeled (PASL) perfusion magnetic resonanceMRI scanning. We found that compared to control subjects, HUD showed worse neuropsychological performance and significantly decreased regional relative CBF ((rCBF)) in HUD patients had hypoperfusion in limbic, frontal, and temporol areas,and the correlation between middle frontal gyrus(MFG) and theneurocognitive measures.

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Energy usage of a newly operational GE Healthcare Signa Premier 3T MRI
Geraldine N Tran1, Maria K Pamatmat1, Craig Devincent1, Gail Lee2, and Alastair J Martin1

1Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Sustainability, University of California, San Francisco, San Francisco, CA, United States

Healthcare is a leading producer of carbon emissions with radiology as a key contributor. Our study describes the GE Premier's energy consumption. When operational for 10 hours in a 24 hour day, the GE Premier consumed 57.69 kwh, which is over double the energy consumption of the average household. Individual scans require 2.44-4.98 kwh; refrigerators use 1-2 kwh a day. Ready-to-scan and scanning modes require 4-10x the power of off mode. Optimizing the use of off mode will yield energy savings, and comparison to other models may guide environmentally conscious expansion of radiology services.

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Let’s play! The MR escape room
Stefano Mandija1,2, Tim Schakel1,2, and Rob H.N. Tijssen1,2

1University Medical Center Utrecht, Utrecht, Netherlands, 2Utrecht University, Utrecht, Netherlands

To create an innovative teaching method that engages students new to MR. The MR Escape room is a fun game that tests the (newly acquired) knowledge of students, while doubling as a team building exercise.

3679
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A Dedicated Head-Only MRI Scanner for Point-of-Care Imaging
Alex Panther1, Gilbert Thevathasen1, Ian R.O. Connell2, Yi Yao1, Curtis N Wiens1, Andrew T Curtis1, Geron A Bindseil1, Chad T Harris1, Philip J Beatty1, Jeff A Stainsby1, Charles H Cunningham3, B A Chronik2, and Cameron Piron1

1Synaptive Medical, Toronto, ON, Canada, 2Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada, 3Department of Medical Biophysics, Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada

A dedicated head-specific MRI is presented.  The MRI is designed to address many of the siting and installation requirements to better allow the use of MRI in point-of-care imaging.

3680
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HCC screening with abbreviated MRI: retrospective comparison of noncontrast, dynamic-contrast enhanced and hepatobiliary phase protocols post gadoxetic acid
Naik Vietti Violi1, Miriam Hulkower2, Joseph Liao2, Gabriela Hernandez-Meza3, Katherine Smith4, Xing Ching2, Joseph Song2, Eitan Novogrodsky5, Daniela Said1, Shingo Kihira2, Mark Berger2, Maxwell Segall1, Keith Sigel6, Mary Sun3, Dillan Villavisanis3, Claude B Sirlin7, Sara Lewis1,2, and Bachir Taouli1,2

1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Icahn School of Medicine at Mount Sinai, New York, NY, United States, 4Columbia University, New York, NY, United States, 5Radiology, Albert Einstein College of Medicine, New York, NY, United States, 6Infectious diseases, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 7Radiology, UC San Diego Medical Center, San Diego, CA, United States

In this study, we compare the performance of different abbreviated MRI (AMRI) protocols using 3 different sets: noncontrast, dynamic T1WI, and hepatobiliary phase (HBP) post gadoxetic acid for hepatocellular carcinoma (HCC) screening in 238 patients at risk. Our results showed that performance of noncontrast AMRI was low, while AMRI using dynamic T1WI and AMRI including HBP showed equivalent sensitivity for HCC detection with slightly better specificity for dynamic T1W. These results need verification in a larger study.


fMRI: Preclinical

Exhibition Hall
Wednesday 13:30 - 14:30
 fMRI

3681
Computer 1
Sex-linked neurofunctionnal basis of psychological resilience in late adolescence
Cheng Yang1, Song Wang1, and Qiyong Gong1

1Huaxi MR Research Center, West China Hospital, Sichuan University, Chengdu, China

Psychological resilience refers to the ability to bounce back from  adversity and previous studies have shown sex differences in psychological resilience. Here, we employed amplitude of low-frequency fluctuations (ALFF) to investigate sex differences in the relationship between resting-state brain activity and psychological resilience in 231 healthy adolescents. Behaviorally, we found that males were more resilient than females. Neurally, a positive correlation between psychological resilience and the ALFF in the right orbitofrontal cortex was detected among males while a negative correlation was observed among females. Together, our study provided the first evidence of sex-specific neurofunctional substrates underlining psychological resilience in adolescents. 

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Gender differences in the relationship between gray matter structure and psychological resilience in late adolescence
Cheng Yang1, Song Wang1, and Qiyong Gong1

1Huaxi MR Research Center, West China Hospital, Sichuan University, Chengdu, China

Although behavioral studies have shown that males are more resilient than females, the effects of gender on the relationship between brain structure and psychological resilience are largely unknown. Here, we investigated the gender-specific associations between psychological resilience and regional gray matter volume (GMV) in 231 healthy adolescents via structural magnetic resonance imaging. We found that the relationship between psychological resilience and GMV differed between genders in the left ventrolateral prefrontal cortex, with a positive correlation in males and a negative correlation in females. Therefore, our study provided the first evidence for the gender-specific neuroanatomical correlates of psychological resilience. 

3683
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Effects of Omega-3 Fatty Acids on Brain Connectivity in Long-Evans Rats
Adebayo B Braimah1,2, Diana M Lindquist1, Ruth Asch3, Jennifer Schurdak3, and Robert McNamara3

1Imaging Research Center, Department of Radiology, Cincinnati Children's, Cinicinnati, OH, United States, 2Pediatric Neuroimaging Research Consortium, Cincinnati Children's, Cinicinnati, OH, United States, 3UC Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, United States

This study examines the impact of dietary fatty acid intake on functional connectivity of the maturing brain. This study was performed with 88 rats. In vivo as well as ex vivo neurological data was collected by means of MR imaging and postmortem gas chromatography. The graphs were compared by using network-based statistics and showed non-significant trends between the controls and the fatty-acids deficient group. Network metrics were also computed and showed non-significant trends between the controls and the fatty acids deficient group. 

3684
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Stress and the brain: Perceived stress mediates the impact of the superior frontal gyrus spontaneous activity on depression in late adolescence
Song Wang1 and Qiyong Gong1

1Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China

Perceived stress (PS), which reflects the tendency to appraise one’s life situations as stressful and overwhelmed, is a stable predictor for depression. Here, we used resting-state functional magnetic resonance imaging to investigate the neural basis of PS and the underlying brain mechanism linking PS and depression in 217 adolescents. We found that PS was positively related to the spontaneous activity in the left superior frontal gyrus (SFG). Furthermore, PS mediated the link between the left SFG activity and depression. Altogether, our study might present a neurofunctional marker of PS and reveal an underlying brain-stress mechanism for predicting depression.

3685
Computer 5
Odor stimulation by automated syringe pumps in combination with the independent component analysis for BOLD-fMRI study of mouse whole brain
Fuyu Hayashi1, Mitsuhiro Takeda1, Naoya Yuzuriha1, Sosuke Yoshinaga1, and Hiroaki Terasawa1

1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan

Olfactory perception in mice involves the activation of brain regions. We previously developed a method that uses repetitive odor stimulation and independent component analysis (ICA) for BOLD-fMRI studies.  Using BOLD-ICA, we sought to detect odor-evoked responses in the mouse whole brain. Previously, the administration of an odorant substance had been performed by manually operating a syringe pump to infuse the saturated vapor of an odorant substance. We constructed a system that automatically controls the syringe pump, to ensure the accuracy of stimulation timing and duration. We demonstrate the improved detectability in the BOLD-ICA method by the automated system.

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Structural and Resting-State Functional Connectivity Changes of the MPS I Mouse Brain
Wei Zhu1, Yi Zhang1, Yucong Ma2, Kyle Schaible3, Nanyin Zhang2, Xiao-Hong Zhu1, Perry Hackett4, Walter Low3, and Wei Chen1

1Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 2Department of Biomedical Engineering, Penn State University, State College, PA, United States, 3Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States, 4College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States

Mucopolysaccharidoses (MPSs) is a group of inherited lysosomal storage disorders that could cause multiple organ failure, cognitive impairment, and shortened life span. In spite of the recognizable clinical morphological and physiological features associated with MPSs, brain connectivity changes and physiopathologic mechanisms responsible for these alterations in the central nervous system are rarely studied but might be a reliable biomarker for disease severity and treatment efficacy. A new study of brain connectome on MPS I mouse model using resting-state functional MRI (rs-fMRI) technique was conducted and a dramatic deterioration on functional connections involving multiple brain regions were observed.

3687
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BOLD-fMRI evaluation of analgesic candidates with different analgesic mechanisms against allodynia-specific pain in a chronic pain animal model
Mikio Sameshima1, Sosuke Yoshinaga1, Naoya Yuzuriha1, Mitsuhiro Takeda1, and Hiroaki Terasawa1

1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan

The aim of this study is to evaluate the pain-relieving effect of a novel chemokine signal-inhibiting compound on allodynia-specific responses in a chronic pain animal model, using our BOLD-fMRI-based pain evaluation system with a green laser. We observed activations in four brain regions related to pain. We found that the compound suppresses green laser-evoked allodynia-specific responses in three regions. We expect that the compound has synergistic pain-relieving effects with existing analgesic agents. Our system is useful to evaluate the effects of new analgesic candidates in non-clinical and, expectantly, clinical studies.

3688
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Altered bilateral functional connectivity in rat brain under isoflurane and medetomidine anesthesia
Ting Yin1, Rolf Gruetter1, and Ileana Ozana Jelescu1

1CIBM-AIT, École polytechnique fédérale de Lausanne, Lausanne, Switzerland

Anesthetic agents are commonly used in rodent resting-state functional MRI. When anesthetized under different agents, brain functional connectivity can be altered. It has been shown that after isoflurane initiation, brain connectivity measured under medetomidine was extensively affected in a time-dependent manner. Here, we further compare the difference of resting-state networks detected under isoflurane and medetomidine anesthesia.

3689
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An awake mouse MRI method using mouse clothes for fMRI applications
Sosuke Yoshinaga1, Satoshi Fujiwara1, Shunsuke Kusanagi1, Kazunari Kimura1, Rikita Araki2, Mitsuhiro Takeda1, and Hiroaki Terasawa1

1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan, 2Bruker Japan K.K., Yokohama, Japan

In current awake MRI methods, fixing apparatuses implanted in the brain by surgery and acclimation procedures by training have been explored, to suppress head movement in the scanner. Previously, we reported an awake MRI method using mouse clothes designed for a cryogenic coil system, without surgery and training. We now report the successful optimization of the awake mouse MRI method for fMRI applications, using the newly designed mouse clothes. Resting-state analyses showed bilateral functional connectivities in the cortical and limbic system networks in an awake mouse. Our method will contribute to the acquisition of awake-specific neuronal responses.

3690
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Awake Macaque MRI Setup on 7T Human Scanner Platform for High-Resolution Anatomical and Functional Imaging
Yang Gao1, Meizhen Qian1,2, Pinyi Wang1, Yi Sun3, Anna Wang Roe1,2, and Xiaotong Zhang1

1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, 2School of Medicine, Zhejiang University, Hangzhou, China, 3MR Collaboration Northeast Asia, Siemens Healthcare, Hangzhou, China

We introduced a customized setup for awake sitting macaque MRI in a 7T horizontal-bore human scanner. Considerations in the specialized design of monkey cage and head fixation device consisting of 1) monkey comfort in a Sphinx position, 2) stable head fixation, 3) easy mounting of the surface array for cortex imaging, and 4) easy presentation of visual stimuli. Our findings demonstrate that, in a well-trained awake monkey, with the increased contrast sensitivity and substantial gains in spatial resolution offered by ultra-high field MRI and a custom-made dense RF array, our setup is capable of achieving improved SNR and high time efficiency.

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Are fMRI measurements in medetomidine-anesthetized rats temporally stable?
Nikoloz Sirmpilatze1,2, Jürgen Baudewig1, and Susann Boretius1,2

1Functional Imaging Laboratory, German Primate Center, Göttingen, Germany, 2Georg-August University of Göttingen, Göttingen, Germany

Medetomidine is often used to anesthetize rats during BOLD fMRI, yet the exact protocols for its administration differ across studies, compromising comparability and raising questions regarding the stability of fMRI measurements over several hours of anesthesia. We performed multiple repeated measurements of somatosensory and resting-state fMRI in medetomidine-anesthetized rats for up to six hours. Four different protocols of medetomidine administration were tested for their capacity to sustain stable measures of stimulus-evoked response and functional connectivity. The reported results are expected to help researchers in choosing the administration regime best suited for their needs.

3692
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Neurological, Physiological, and Behavioral Effects Following Acute Cannabis Nose-Only Exposure in C57BL/6J Mice
Yasmeen Farra1, Dongyang Yi1, James Coleman2, Praveen Kulkarni2,3, Craig Ferris2,3, Jessica Oakes1, and Chiara Bellini1

1Bioengineering, Northeastern University, Boston, MA, United States, 2Center for Translational Neuroimaging, Northeastern University, Boston, MA, United States, 3Psychology, Northeastern University, Boston, MA, United States

Cannabis use is rising worldwide. Robust standardized methodologies in animal models are needed to further elucidate the impact of cannabis on overall health. Our aim was to identify acute exposure methods that provide a viable model for human cannabis consumption. C57BL/6J mice were exposed to cannabis aerosols using a Volcano® vaporizing device. Cannabis dosage levels were identified that elicited a human-like response.  Animals were exposed while undergoing fMRI scans of their neurological activity. BOLD data, coupled with blood pressure and behavioral tests, demonstrated that our exposure methods generated a reproducible response that can be adapted for further studies.

3693
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Examining fMRI time-series Multi-Scale Entropy as a Biomarker for Excitation/Inhibition Balance in the Brain
Kaundinya Gopinath1, Eric Maltbie2, Leonard Howell2, and Phillip Sun2

1Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, United States, 2Yerkes National Primate Center, Emory University, Atlanta, GA, United States

The maintenance of a dynamic balance between excitatory and inhibitory synapses in the neocortex is critical for brain function. Many psychiatric disorders are characterized by disturbance of E/I balance. In this study we examined the potential of the fMRI time-series complexity metric multi-scale entropy (MSE) to act as a biomarker for E/I balance, using a non-human primate (NHP) model. We disturbed the E/I balance with the sub-anesthetic ketamine, which induces disinhibition of projection neurons, especially in prefrontal cortex (PFC) during fMRI of conscious NHPs. Our results confirmed that fMRI MSE is a sensitive marker for E/I balance in the brain.

3694
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Tuning Neuromodulation Effects by Orientation Selective Deep Brain Stimulation in the Rat Medial Frontal Cortex
Lauri J Lehto1, Pavel Filip1,2, Hanne Laakso1,3, Alejandra Sierra3, Julia Slopsema4, Matthew D Johnson4, Lynn E Eberly5, Walter C Low6, Olli Gröhn3, Heikki Tanila3, Silvia Mangia1, and Shalom Michaeli1

1Center Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2First Department of Neurology, Faculty of Medicine, Masaryk University and St. Anne’s Teaching Hospital, Brno, Czech Republic, 3A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 4Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States, 5Division of Biostatistics, University of Minnesota, Minneapolis, MN, United States, 6Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States

With simultaneous fMRI and Deep Brain Stimulation (DBS), we demonstrate modulation of activity in rat amygdala by using axon Orientation Selective Stimulation (OSS) DBS in rat infralimbic cortex, a homologue brain region for treating depression in humans. Our results demonstrate orientation selectivity based on number of activated pixels especially in the amygdala, though qualitatively also other brain areas showed modulation based on stimulation angle. OSS may add a new level of optimization for treating major depression disorders.

3695
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Sound-evoked functional magnetic resonance imaging of tinnitus and hyperacusis neural mechanisms
Eddie Wong1, Benjamin Auerbach2, Richard Salvi2, Ed Wu1, and Condon Lau3

1Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, 2Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, United States, 3Department of Physics, City University of Hong Kong, Kowloon Tong, Hong Kong

Tinnitus involves the perception of sound in the absence of external acoustic stimuli. The underlying mechanisms of tinnitus have been investigated using noninvasive, whole brain functional imaging methods. However, the changes in the subcortical auditory system are less well understood. To address this knowledge gap, we conduct an auditory fMRI on a well-established sodium salicylate-induced rodent tinnitus and hyperacusis model. The results reveal frequency-dependent changes in auditory subcortical structures, inferior colliculus and lateral lemniscus by salicylate induced tinnitus. This study has advanced our understanding of subcortical auditory processing during tinnitus/hyperacusis and advances the rat model for further fMRI investigations.

3696
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Reduced brain functional connectivity induced by generalized pain identified by mice Rs-fMRI
Md Taufiq Nasseef1, Emmanuel Darcq1, Waiya Ma1, Jai Puneet Singh1, Naoki Dozono2, Kevin Lancon3, Philippe Seguela3, Hiroshi Ueda2, and Brigitte L. Kieffer1

1Department of Psychiatry, Mcgill University, Montreal, QC, Canada, 2Department of Pharmacology and Therapeutic Innovation, Nagasaki University Institute of Biomedical Sciences Nagasaki, Nagasaki, Japan, 3Department Neurology & Neurosurgery, Mcgill University, Montreal, QC, Canada

Fibromyalgia (FM) is a disorder characterized by generalized pain. The acid saline-induced muscle (ASM) model is considered an acceptable animal model of FM with widespread chronic pain. Here, we investigated the impact of FM-like pain on neural communication, using the ASM model with non-invasive mouse resting state fMRI. We found that generalized pain reduces functional connectivity at the level of periaqueductal gray and retrosplenial cortex, two regions related to pain processing and FM. Moreover, we found a positive correlation between pain sensitivity measured by Von Frey test and the intensity of FC reduction at individual subject level. 

3697
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Comparisons of resting-state networks obtained at 3 and 7 Tesla MRI in anesthetized rhesus monkey
Chan-Ung Park1, Eunha Baeg1, Boo-Hee Choi1, Bo-yong Park 1,2, Hyunjin Park 1,3, and Seong-Gi Kim1,4

1Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea, Republic of, 2Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, Korea, Republic of, 3School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of, 4Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of

Understanding resting-state fMRI (rsfMRI) is an important issue to identify the functional principles of the normal and pathological brain networks. Despite the importance in comprehending network as a whole, a deeper understanding of the resting-state networks is limited due to the lack of a proper animal model. Here, we used anesthetized non-human primate (NHP) for understanding rsfMRI networks commonly detected in humans. BOLD and MION-enhanced CBV rsfMRI networks were obtained at 3T and 7T. Stable eight cortical networks were observed from MION experiments at 3T and 7T, and similar networks were also detected from 7T BOLD due to enhanced sensitivity.

3698
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Signal changes in functional diffusion measurements in rats are not caused by tissue heating, but have a vascular contribution
Franziska Albers1, Daniel Schache1, Lydia Wachsmuth1, Henriette Lambers1, and Cornelius Faber1

1Translational Research Imaging Center (TRIC), University Hospital Muenster, Muenster, Germany

Functional diffusion MRI has been proposed as an alternative to BOLD fMRI, to offer a more direct read-out of neuronal activation. One aspect of the controversial discussion around functional diffusion is whether these signals follow the neuronal activation more closely. We performed BOLD and diffusion measurements with 250 ms temporal resolution upon sensory stimulation and found similar temporal evolutions for BOLD and diffusion signals. Specifically, both signals slowly returned to baseline after the stimulus. However, diffusion measurements with b=500 showed an earlier onset. We performed heat application to rule out tissue heating as a contribution to functional diffusion signals.

3699
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Effects of Isoflurane on Brain Functional Connectivity in Common Marmosets
Naoki Kawaguchi1,2, Junichi Hata3, Yawara Haga3,4, Kanako Muta5, Koya Yachida1,3, Koshiro Terawaki1,2, Hirotaka James Okano2, Hideyuki Okano3, and Akira Furukawa4

1Department of Radiological Sciences, Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo, Japan, 2Regenerative medicine, The Jikei University School of Medicine, Tokyo, Japan, 3Laboratory for Marmoset Neural Architecture, Center for Brain Science, RIKEN, Wako, Japan, 4Department of Radiological Sciences, Human Health Sciences, Tokyo Metropolitan University Graduate School, Tokyo, Japan, 5Veterinary Surgery Laboratory, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan

We examined the effects of isoflurane on brain functional connectivity in common marmosets using resting-state fMRI. We found that the thalamus was closely related to the mechanism of action of anesthesia and the default mode network (DMN), which is thought to function at rest. Isoflurane exhibited similar effect on the thalamus and human DMN region in humans but partly different effect onthe marmoset DMN region.In the future, we need to perform further investigations in detail by increasing the amount of data and reviewing analysis methods.

3700
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Identification and Characterization of Resting State Networks in the Translational Pig Model
Gregory Simchick1,2, Alice Shen3, Hea Jin Park4, Franklin West5, and Qun Zhao1,2

1Physics and Astronomy, University of Georgia, Athens, GA, United States, 2Bio-Imaging Research Center, University of Georgia, Athens, GA, United States, 3University of Georgia, Athens, GA, United States, 4Foods and Nutrition, University of Georgia, Athens, GA, United States, 5Animal and Dairy Science, University of Georgia, Athens, GA, United States

Due to the similar size, structure, composition, and neurodevelopment of the pig brain in comparison to the human brain, the pig serves as a valuable large animal model for studying brain connectivity. Presented here are five resting state networks (RSNs) identified within the three-week-old piglet brain determined using temporal sparse dictionary learning. Each RSN’s learned activation map correlates well with a constructed pig RSN atlas with Pearson spatial correlation coefficients in the range of [0.30 0.53], and clear differences in the power spectra, as well as unique characteristic frequencies, associated with the learned signal for each RSN are observed. 

3701
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Creation and evaluation of a generic rat hemodynamic response function for analysis of BOLD fMRI measurements
Henriette Lambers1, Martin Segeroth1, Franziska Albers1, Lydia Wachsmuth1, Timo Mauritz van Alst1, and Cornelius Faber1

1Translational Research Imaging Center (TRIC), University Hospital Muenster, Muenster, Germany

For a reliable analysis of BOLD fMRI data, a suitable model of the hemodynamic response is essential.  Therefore, an accurate model of the BOLD response of small animals is required in preclinical studies. Commonly used analysis tools like SPM or BrainVoyager have implemented HRFs optimized for humans by default. Since the BOLD responses of rats proceed faster than those of humans, we have determined a generic rat HRF based on 98 BOLD measurements of 35 rats which can be used for statistical parametric mapping. Statistical analysis of rat data showed a significantly improved detection performance using this rat HRF.

3702
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The Effect of IC Number Selection in Group ICA for Rat Functional Connectivity
Tyng-Shiuan Hsieh1,2, Chia-Feng Lu3, Bao-Yu Hsieh4, Cheng-Yu Chen2,5,6,7, and Yu-Chieh Jill Kao2,6,7

1School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 2Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan, 3Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, 4Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan, 5Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan, 6Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 7Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan

   Optimal IC number used in the ICA has been a kernel issue for functional MRI (fMRI) analysis. Nevertheless, limited consensus in IC number selection was proposed for rodent brains. This study aims to explore the effect of IC numbers in rsfMRI analysis in rats and further compare the difference using two echo-planar image (EPI) protocols with commonly used in-plane resolution (546 µm vs. 208 µm). We demonstrated the similar pattern of functional regions as IC number increases using both EPI protocol, suggesting the feasibility to perform routinely used EPI protocol for rsfMRI in rats. 

3703
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Network structure of the mouse brain connectome with voxel resolution
Ludovico Coletta1,2, Marco Pagani2, Boris Bernhardt3, and Alessandro Gozzi2

1Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy, 2Functional Neuroimaging Laboratory, Center for Neuroscience and Cognitive Systems @ UniTn, Istituto Italiano di Tecnologia (IIT), Rovereto, Italy, 3Multimodal Imaging and Connectome Analysis Lab, Montreal Neurological Institute, McGill University, Montreal, QC, Canada

We provide a fine-grained description of the network structure and topology of the mouse connectome with voxel-resolution. We show that structural connectivity hubs can be spatially segregated into a dichotomic set of neural sink and neural source regions, and that functional and structural hubs show concordant neuro-anatomical topography. We finally demonstrate that the modular structure of the mouse connectome recapitulates large-scale fMRI networks of the mouse brain, including a default mode network core community, which is characterized by high structural resilience. Our results lay the foundation for topologically-driven targeted manipulations of the mouse connectome.

3704
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Sympathetic Contribution in Somatosensory Mouse fMRI: Revealing "Hidden" Key Structure Activations by Detailing Functional Response Dynamics
Henning Matthias Reimann1, Mihail Todiras2, André Klage1, Michael Bader2,3, Andreas Pohlmann1, and Thoralf Niendorf1,4

1Berlin Ultrahigh Field Facility, Max-Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany, 2Max-Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany, 3DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany, 4Experimental and Clinical Research Center, A Joint Cooperation Between the Charite Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany

Electrostimulation of the paw is considered a basic paradigm to produce a reliable somatosensory response in animal fMRI. Yet, there is disagreement over the murine BOLD response: based on the anesthetic protocol either unilateral or bilateral patterns were reported. We hypothesize sympathetic activity as an origin of bilateral patterns, which is likely to be suppressed in protocols that employ α2-adrenoreceptor agonists. Utilizing finite impulse response (FIR) basis set modeling we present preliminary data that reveals "hidden" activity of brain structures which are known driving forces of sympathetic pathways. Our overall aim is to reveal the underlying mechanisms of this complex response to a simple paradigm and its implications for somatosensory mouse fMRI.


fMRI: Physiology

Exhibition Hall
Wednesday 13:30 - 14:30
 fMRI

3705
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Normal variations in brain oxygen extraction fraction (OEF) are partly attributed to differences in end-tidal CO2
Dengrong Jiang1, Zixuan Lin1, Peiying Liu2, Sandeepa Sur2, Cuimei Xu2, George Pottanat2, Kaisha Hazel2, Sevil Yasar3, Paul Rosenberg4, Marilyn Albert5, and Hanzhang Lu2

1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 5Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Quantitative assessment of brain oxygen extraction fraction (OEF) is of substantial clinical significance in many brain diseases. However, a remaining issue associated with OEF is its considerable inter-subject variations within healthy population. Therefore, it is important to investigate the physiological underpinnings of OEF variations among normal subjects. The present work used two studies, a discovery study and a verification study, to examine the extent to which end-tidal CO2 (EtCO2) can explain inter-subject variations in OEF. It was found that, across subjects, OEF is inversely correlated with EtCO2, and EtCO2 alone can account for about 50% of variances in OEF.

3706
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Whole-brain OEF quantification: a comparison study between QSM and dual-gas calibrated BOLD
Yuhan Ma1, Hongfu Sun2, Junghun Cho3,4, Erin L. Mazerolle2, Yi Wang3,4, and G. Bruce Pike1,2

1McConnell Brain Imaging Centre and Department of Biomedical Engineering, McGill University, Montreal, QC, Canada, 2Hotchkiss Brain Institute and Department of Radiology, University of Calgary, Calgary, AB, Canada, 3Department of Biomedical Engineering, Cornell University, Ithaca, NY, United States, 4Department of Radiology, Weill Cornell Medical College, New York, NY, United States

The microvascular QSM approach for quantifying baseline brain oxygen metabolism has great potential due to its simple set-up and high spatial resolution. In this study, we aim to investigate the feasibility of the high SNR microvascular QSM-OEF technique with a hypercapnia gas challenge and compare OEF and CMRO2 measured by QSM-OEF with those measured using the dual-gas calibrated BOLD technique (DGC-BOLD-OEF), a reference standard. Baseline OEF and CMRO2 measured by hypercapnia QSM-OEF were found within the expected normal range for healthy subjects. Statistically significant but relatively small differences (5% difference) of OEF and CMRO2 were found between QSM-OEF and DGC-BOLD-OEF techniques.

3707
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The correlation between cerebral venous oxygen saturation change and cognitive score in Alzheimer's disease patients by using susceptibility weighted imaging mapping
Junyi Dong1, Yanwei Miao1, Xiaoxin Li1, Liang Han1, Lizhi Xie2, Qingwei Song1, and Ailian Liu1

1Department of Radiology, First Affiliated Hospital of Dalian Medical University, Dalian,116011,China, Dalian, China, 2GE Healthcare, Beijing, China

Alzheimer's disease (AD) is a progressive neurodegenerative disease and vascular factors may be important in the development and progression of AD[1]. Magnetic susceptibility weighted imaging (SWI) is widely used in the diagnosis of central nervous system diseases, and venous oxygen content is the basis of SWI angiography. The venous blood oxygen level can be reflected by measuring the phase value of venous blood. This study first made use of SWI mapping (SWIM) to measure the change of magnetic susceptibility and the change of blood oxygen and then explores the correlation between cerebral venous oxygen saturation change and cognitive score in AD patients

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Hypercapnic Normalization to Correct for Caffeine-Induced Changes in Task-Based BOLD fMRI Responses
Jacinta L. Specht1, Rebecca J. Williams1, Erin L. Mazerolle1, and G. Bruce Pike1

1Radiology and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada

This repeated-measures study sought to determine whether hypercapnic normalization can be used to address caffeine-induced vascular changes affecting BOLD responses. Visual/motor BOLD activation and cerebrovascular reactivity (CVR) under caffeine and placebo conditions were examined. CVR-correction was performed by dividing the task BOLD signal by CVR. Prior to CVR-correction, peak BOLD responses for both caffeine and placebo conditions were found in the visual cortex. After CVR-correction, peak responses were in the subcortical regions. Caffeine produced larger responses in the cerebellum compared to placebo, while subcortical activation was larger under placebo conditions. These results show that CVR-correction may benefit subcortical signal detection.  

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The temporal stability of BOLD is improved by calibrating the cerebral vascular reactivity underpinned by the vascular probability within the group
Yi-Tien Li1,2, Jacky Tai-Yu Lu3, Ren-Horng Wang3, Pu-Yeh Wu1, Ying-Hua Chu1, and Fa-Hsuan Lin1,4,5

1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 2Department of Medical Imaging, Taipei Medical University - Shuang-Ho Hospital, New Taipei, Taiwan, 3Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 4Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland, 5Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada

We hypothesize that the local venule vasculature underlies the BOLD signal latency and its variability. This hypothesis was tested by measuring the BOLD signal in the human primary visual cortex with a 10-Hz sampling rate during a visuomotor and a breath-holding (BH) task. A venule probability (VP) map was estimated by susceptibility-weighted images. We found that VP was significantly correlated to the  relative BOLD latency and relative latency variability during the visuomotor task. These correlations disappeared after subtracting the latency in the BH task from the latency in the visuomotor task. These results support our hypothesis.

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The neurovascular response is attenuated by focused ultrasound-mediated disruption of the blood-brain barrier
Nick Todd1, Yongzhi Zhang1, Margaret Livingstone2, David Borsook3, and Nathan McDannold1

1Brigham and Women's Hospital, Boston, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Boston Children's Hospital, Boston, MA, United States

Focused ultrasound (FUS) disruption of the blood-brain barrier (BBB) is a promising technology for achieving targeted delivery of pharmacological agents into the brain. While the method has been shown to be safe from the standpoint of not damaging tissue cells, it causes other changes to local physiology that are not fully understood. This study aims to characterize the effects on the hemodynamic response that FUS BBB opening causes. We present BOLD and CBF fMRI results to investigate the particular mechanisms within the neurovascular response responsible for this effect.

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Increased Blood-Brain Barrier Water Permeability in the Visual Cortex in Response to Visual Stimulation
Kenneth Wengler1, Kwan Chen2, Mark E Schweitzer2, and Xiang He2

1Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 2Radiology, Stony Brook University, Stony Brook, NY, United States

Evidence of cell swelling upon activation has been observed in early diffusion functional MRI studies, and has been attributed to the co-transported water due to transient changes in ionic transmembrane flux. Blood-brain barrier (BBB) water permeability is also believed to be a marker of cerebral metabolism. Here we provide an initial investigation of visual stimulation on BBB water permeability parameters, water extraction fraction (Ew) and permeability surface area product (PSw), using the recently developed Intrinsic Diffusivity Encoding of Arterial Labeled Spins (IDEALS). Significant increase of PSw were observed with no change of Ew in the visual cortex during visual stimulation.

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Improved sensitivity for detecting functional CBF changes by center-out EPI with very short echo time
Ratnamanjuri Devi1, Toralf Mildner1, Kathrin Lorenz1, Jöran Lepsien1, and Harald E. Möller1

1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

Compared to BOLD imaging, the detection of functional CBF changes by arterial spin labeling is difficult due to the inherently small signal changes in the range of one percent or less. We compared a multi-echo EPI readout to center-out EPI that achieves a very short TE. The reduction of the minimum TE from 9.3 ms (multi-echo EPI) to a value of 1.8 ms (center-out EPI) yielded significantly improved statistical power in the human visual cortex in addition to diminished confounding BOLD and physiological noise contributions.

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Measurements and modeling of the negative hemodynamic response function in human early visual cortex
David Ress1, Natasha DeLaRosa1, and Jung Hwan Kim1

1Neuroscience, Baylor College of Medicine, Houston, TX, United States

A negative BOLD response is often observed in early visual cortex. Previous measurements  indicate that negative BOLD is the consequence of flow decreases. However, negative BOLD is usually evoked by blocked experimental designs that obscure details of their temporal dynamics. To understand the physiology of the negative BOLD, we used a slow event-related paradigm to elicit strong hemodynamic response functions (HRFs) in primary visual cortex as a function of eccentricity. We used a modified version of the Arterial Impulse Model to predict the neurovascular and neurometabolic mechanisms of negative BOLD. Results indicate that negative BOLD physiology is profoundly different than positive BOLD with greater non-linearity.

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Quantifying and Correcting for the Assumptions of the Static Dephasing Regime in Quantitative BOLD
Matthew T Cherukara1,2, Michael A Chappell1,2, and Nicholas P Blockley2,3

1Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom, 2Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 3School of Life Sciences, University of Nottingham, Nottingham, United Kingdom

The effect of diffusion is believed to cause underestimation of oxygen extraction fraction (OEF) in streamlined quantitative BOLD (qBOLD). We propose physically motivated modifications to the qBOLD model in order to account for this effect, and demonstrate, using Monte Carlo simulations, and analysis of healthy in vivo data, that simple scalar corrections to the inferred reversible relaxation rate $$$R_2'$$$, can substantially reduce the error in OEF and deoxygenated blood volume (DBV) estimation. These corrections have the potential to be improved further by taking other physiological and acquisition-related parameters into account.

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Quantification of draining vein dominance across cortical depths in BOLD fMRI from first principles using realistic Vascular Anatomical Networks
Joerg P. Pfannmoeller1,2, Avery J. L. Berman1,2, Sreekanth Kura3, Xiaojun Cheng3, David A. Boas1,3, and Jonathan R. Polimeni1,2,4

1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Neurophotonics Center, Department of Biomedical Engineering, Boston University, Boston, MA, United States, 4Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

The neuronal specificity of gradient echo (GE) BOLD is diminished by the extravascular signal from large draining veins, whose contribution can be reduced by using small voxel sizes and sampling far away from the cortical surfaced. Here we use simulations of the GE-BOLD signal based on a realistic vascular network (VAN) to quantify the extent of the pial vein dominance into the cortex field strengths between 7 and 14 Tesla. We estimate a pial vessel dominance down to a depth of 800 μm at 14 Tesla in humans, suggesting that small GE-BOLD voxels below this depth can be immune to the effects of these surface vessels.

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A frequency-domain machine learning (FML) method for dual-calibrated estimation of oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen metabolism (CMRO2)
Michael Germuska1, Hannah L Chandler1, Rachael C Stickland1, Catherine Foster2, Jessica Steventon1, Valentina Tomassini1, Kevin Murphy1, and Richard G Wise1

1Cardiff University, Cardiff, United Kingdom, 2Concordia University, Montreal, QC, Canada

A frequency-domain machine learning method is presented that significantly reduces the bias and variance in dual-calibrated estimation of oxygen extraction fraction, as demonstrated with simulation and in-vivo imaging. In addition, the method substantially reduces the processing time compared to previous robust analysis methods.

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fMRI investigation of the role of interhemispheric interactions in cortical sensory processing
Eddie C. Wong1,2, Alex L. T. Leong1,2, Xunda Wang1,2, Celia M. Dong1,2, and Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China

Effective sensory communications require massive interconnected interhemispheric cortico-cortical projections. However, little is known at present regarding the exact interactions that occur bilaterally between sensory cortices across the brain hemispheres and how they influence cortical processing. Here, we employ optogenetic stimulation of the whisker-related thalamic excitatory neurons in combination with the somatosensory forepaw stimulation. We demonstrate a novel platform to investigate the interhemispheric interactions underlying cortical sensory processing.

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Elevated activation of a murine limbic network during cue-reward association learning revealed in 15.2 T fMRI
Keisuke Sakurai1, Shota Ando1, Chihiro Takahashi1, Teppei Shintani1, Wonbeom Jung2, Dinh Thi Ngoc Anh2, Chanhee Lee2, Yunbok Kim2, Seong-Gi Kim2, and Tatsuhiro Hisatsune1

1Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan, 2Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea, Republic of

An operant learning device for head-fixed mouse was developed for ultra-high field (15.2 Tesla) fMRI. Habituated mice were learned to water reward, associated with cue of light stimulation as a conditioning stimulus. We obtained 1,000 sets of BOLD fMRI (GE-EPI, TR/TE = 1000/11 ms), and found that elevated activation of a limbic learning network, including the entorhinal, perirhinal, and retrosprenial cortices and the hippocampal formation, during cue-reward association in learned mice.

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Sympathetic contribution of respiratory effects to the fMRI signal
Pinar S Ozbay1, Catie Chang2, Jacco A de Zwart1, Peter van Gelderen1, and Jeff H Duyn1

1NINDS, NIH, Bethesda, MD, United States, 2Vanderbilt University, Nashville, TN, United States

fMRI signal covariation with fluctuations in systemic physiology, including cardiac rate and respiration, is well established. Recent work showed strong correlations between peripheral vascular tone, a proxy for sympathetic activity, and fMRI global signal during drowsiness and sleep. As sympathetic activity may also be triggered by inspiration, even during the alert waking condition typical of task fMRI, we investigated the relationship between respiration, peripheral vascular tone, and fMRI signal during a visual task.

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Cerebrovascular Reactivity (CVR) mapping using intermittent breath modulation
Peiying Liu1, Cuimei Xu1, and Hanzhang Lu1

1Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Cerebrovascular reactivity (CVR) mapping is typically performed using CO2-inhalation or breath-holding as a vasoactive challenge while collecting BOLD images. Recently, resting-state BOLD has been used to map CVR by utilizing spontaneous fluctuations in breathing pattern, but the results could be noisy in subjects with little fluctuation in their spontaneous breathing. Here we developed a new technique for CVR mapping that does not require gas-inhalation yet provides substantially higher sensitivity than resting-state CVR mapping. This new technique is largely based on resting-state scan, but introduces intermittent modulation of breathing pattern in the subjects to enhance fluctuations in their end-tidal CO2 level.

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Breath-hold BOLD-fMRI cerebrovascular reactivity metrics predict cognitive impairment in cerebral small vessel disease
Joana Pinto1, Tânia Charrua1, Ana Fouto1, Luísa Alves2,3, Sofia Calado2,3, Carina Gonçalves2,3, Margarida Rebolo4, Miguel Viana Baptista2,3, Pedro Vilela5, Rita G Nunes1, and Patrícia Figueiredo1

1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico – Universidade de Lisboa, Lisboa, Portugal, 2Neurology Department, Hospital Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisboa, Portugal, 3CEDOC - Nova Medical School, New University of Lisbon, Lisboa, Portugal, 4Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal, 5Imaging Department, Hospital da Luz, Lisboa, Portugal

Cerebral small vessel disease (SVD) is associated with an increased risk of stroke and dementia, being implicated in age-related cognitive decline. In this work, we investigate the potential of cerebrovascular reactivity (CVR) to provide sensitive biomarkers of SVD, by evaluating metrics extracted from breath-hold BOLD-fMRI in terms of their predictive power of cognitive impairment in a group of SVD patients. We modelled the breath-hold BOLD-fMRI response using a sinusoidal approach, and derived both CVR amplitude and delay-based maps. Multiple linear regression analysis showed that CVR metrics significantly contributed to explain cognitive impairments in working memory, long-term memory and executive function.

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Amplitude of low-frequency fluctuations in resting-state BOLD-fMRI is associated with cognitive decline in cerebral small vessel disease
Joana Moreira1, Joana Pinto1, Ana Fouto1, Luísa Alves2,3, Sofia Calado2,3, Carina Gonçalves2,3, Margarida Rebolo4, Pedro Vilela5, Miguel Viana Baptista2,3, and Patrícia Figueiredo1

1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico – Universidade de Lisboa, Lisboa, Portugal, 2Neurology Department, Hospital Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisboa, Portugal, 3CEDOC - Nova Medical School, New University of Lisbon, Lisboa, Portugal, 4Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal, 5Imaging Department, Hospital da Luz, Lisboa, Portugal

Cerebral small vessel disease (SVD) is a major vascular contributor to dementia and stroke, being associated with age-related cognitive decline. In this work, we aim to assess the potential of spontaneous BOLD fluctuations metrics to predict cognitive impairment in a group of SVD patients, therefore providing sensitive SVD biomarkers. The amplitude of low-frequency fluctuations (ALFF) and fractional ALFF (fALFF) were computed in four different frequency bands as metrics of spontaneous BOLD signal fluctuations. Results from multiple linear regression analyses demonstrated that spontaneous BOLD fluctuations metrics contribute to the prediction of cognitive impairment in executive function, processing speed and working memory.

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Voxel-wise analysis of functional MRI activation in regions of provoked impaired cerebrovascular reactivity: a translational model
Marco Piccirelli1, Christiaan Hendrik Bas van Niftrik1, Giovanni Muscas1, Martina Sebök1, Joseph Arnold Fisher2, Oliver Bozinov1, Antonios Valavanis1, Luca Regli1, Christoph Stippich1, and Jorn Fierstra1

1University Hospital Zurich, Zurich, Switzerland, 2University of Toronto, Toronto, ON, Canada

A voxel-wise investigation of the relationship between the cerebrovascular reactivity (BOLD-CVR) alteration and the task-evoked Blood-oxygenation-level dependent functional MRI (BOLD-fMRI) challenges the commonly accepted linear and global correction method used. Our controlled CVR modulation in healthy subjects is a good investigation translational model for patients affected with glioblastomas or stroke.

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Cerebral blood flow affected by the order of functional tasks
Yaoyu Zhang1,2 and Jia-Hong Gao2

1Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, 2Center for MRI Research, Peking University, Beijing, China

This study investigates the order effect of functional task-induced CBF responses. ASL sequence was implemented to quantify CBF responses to the same task but in paradigms of different task orders in both the motor and visual cortices. Results of the study show an order effect in which that the greater the work load of the prior task, the greater influence it can exert on the CBF response of the posterior task. This study emphasizes the importance of the randomized task design and gives insight on underlying task-induced CBF response mechanisms.

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VASO signal decreases associated with BOLD increases: a possible role of CSF volume redistribution
Marcello Venzi1, Joseph Whittaker1, Laurentius Huber2, and Kevin Murphy1

1School of Physics & Astronomy, Cardiff University, Cardiff, United Kingdom, 2NIMH, Bethesda, MD, United States

Using manipulations of the arterial tension of carbon dioxide, we demonstrate that the paradoxical decrease in CBV associated with BOLD increases is restricted to voxels with large proportions of CSF. Excluding those voxels , we show that visual responses during hypercapnia have no change in amplitude in VASO and BOLD contrasts, but the time-to-peak of BOLD responses lengthens and CBV peak times, being longer at baseline, remain the same.

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Fast fMRI responses supported by inter-voxel variability of hemodynamic response functions
Jingyuan E. Chen1,2, Jonathan R. Polimeni1,2,3, Nina E. Fultz1, Gary Glover4, and Laura D. Lewis1,5

1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Cambridge, MA, United States, 4Radiology, Stanford University, Palo Alto, CA, United States, 5Biomedical Engineering, Boston University, Boston, MA, United States

In this abstract, we use very high-resolution fMRI to evaluate inter-voxel variability of hemodynamic response functions (HRF) elicited by a visual task. We show that HRFs exhibit wide variability across voxels, with a subset of HRFs occurring at temporal scales much faster than the canonical HRF, which we consider as one mechanism that underlie fast neural-activity-related dynamics. Influence of spatial resolution on HRF dynamics are also evaluated, we show that the use of small voxels (without spatial averaging) sampling parenchymal signals may enable faster observed hemodynamics. 

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Title: A Closer Look at the Vascular Component of Hemodynamic Response Function and Its Variations by Aging
Azin Esmaelbeigi1,2, M. Aras Kayvanrad1,2, and J.Jean Chen1,2

1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Rotman Research Institute, Baycrest Centre, Toronto, ON, Canada

It has been shown that the brain vasculature changes with aging. The unhealthy brain vasculature is associated with risks of a lot of conditions such as stroke and ischemic attacks. Moreover, some studies have confirmed the causality of the impaired vasculature and the diseases of aging such as Alzheimer’s disease. Herein, we study the effect of aging on the vascular component of the hemodynamic response function. The results demonstrated narrower and more positively skewed distributions of peak spectral power in older controls which indicate degradation in some regions of the brains of the older adults. 

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The Effect of End-tidal PETCO2 Clamping on Resting-state fMRI Connectivity
Ali M Golestani1 and J. Jean Chen2,3

1Department of Psychology, University of Toronto, Toronto, ON, Canada, 2Rotman Research Institute at Baycrest, Toronto, ON, Canada, 3Medical Biophysics, University of Toronto, Toronto, ON, Canada

The pressure of end-tidal CO2 (PETCO2) has a significant impact on the blood oxygenation level dependent (BOLD) signal and clamping it leads to detecting additional brain activation in task-based fMRI. However, the effect of PETCO2 clamping on the resting state connectivity has not been yet investigated. In this study we compared whole brain connectivity patterns of 13 healthy subjects during free-breathing and clamped PETCO2. Results showed clamping the PETCO2 removes the global and widespread effect of PETCO2 fluctuation in the gray matter, leading to weaker connectivity and more between-subject variability in the connectivity values.

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Deriving cardiac waveforms from fMRI data using slice selective averaging and a deep learning filter.
Serdar Aslan1,2 and Blaise Frederick1,2

1Harvard Medical School, Boston, MA, United States, 2McLean Hospital Brain Imaging Center, Belmont, MA, United States

This work is a new technique to find Cardiac waveform from the fMRI data. For that purpose, a three stage data analysis is performed. In the first two stages, a candidate signal is derived by averaging over the voxels in every slice and combining them with proper time delays and resampling to 25Hz. As the third stage a deep learning architecture is used to improve the signal quality. The reconstructed signal is a good estimate of the plethysmogram data which is collected simultaneously with fMRI data.


Multimodal fMRI

Exhibition Hall
Wednesday 13:30 - 14:30
 fMRI

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Sensorineural hearing loss and cognitive impairments : contributions of thalamus using multimodal MR
Xiao-Min Xu1,2,3 and Gao-Jun Teng1,2,3

1Department of Radiology, Jiangsu Key laboratory of Molecular Imaging and Functional Imaging, Nanjing, China, 2Department of Radiology, Zhongda Hospital, Nanjing, China, 3Medical School of Southeast Univeristy, Nanjing, China

In present study, we systematically investigated the structure, function and perfusion features of the TH and its seven subdivisions through multimodal MRI, aiming to uncover the potential role of the TH in SNHL and its correlations with cognition measurements.

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Altered Brain Structure and Function Correlate with Disease Severity and Affective Disorders in Patients with Hemifacial Spasm
Yuan Wang1, Hui Xu1, Chenguang Guo1, and Ming Zhang1

1Department of Medical Imaging, the first affiliated hospital of Xi'an Jiaotong University, Xi'an, China

Hemifacial spasm (HFS) is characterized by unilateral and paroxysmal contraction of orofacial muscles. A group of HFS patients and healthy controls underwent MRI examination and clinical assessment for facial spasm and affective disorders. HFS patients showed thickened left fusiform in cortex along with reduced subcortical volume in the right amygdala. Increased amygdala-driven connections were revealed to the bilateral superior frontal gyrus (SFG) and orbital gyrus (OG), and increased functional connectivity (FC) was detected of fusiform seed to several subregions of frontal lobe. These altered FC changes were associated with certain clinical indices, providing new insight into pathophysiology of the disease.

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Distinct Patterns of Interhemispheric Connectivity in Patients with Early- and Late-Onset Alzheimer’s Disease
Kaicheng li1, Xiao Luo1, Qingze Zeng1, Peiyu Huang1, Yong Zhang2, and Min-Ming Zhang1

1The 2nd Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China, 2GE Healthcare Shanghai, Shanghai, China

Early-onset Alzheimer’s disease (EOAD) presents a different clinical profile than late-onset Alzheimer’s disease (LOAD). We used voxel-mirrored homotopic connectivity (VMHC) to examine interhemispheric functional connectivity and  tract-based spatial statistics (TBSS) to reflect the diffusion index. We found EOAD patients exhibited more widely disrupted interhemispheric functional and structural connectivity, which related to executive deficits. Our study suggested that different interhemispheric connectivity damage patterns may contribute to the distinctclinical profiles in EOAD and LOAD.

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IVIM-based cerebral perfusion (in ml/100g/min) values at rest, hypercapnia and ischemia in an MCA occlusion model
Mira Liu1, Yong Jeong2, Niloufar Saadat1, Gregory Christoforidis1, and Timothy Carroll1

1Department of Radiology, University of Chicago, Chicago, IL, United States, 2Bioengineering and Biomedical Engineering, Northwestern, Chicago, IL, United States

This is a preliminary study of intravoxel incoherent motion (IVIM) in a two day study of normocapnia, hypercapnia, and post middle cerebral artery occlusion. It was established that IVIM perfusion values are linearly correlated to the reference perfusion values under a variety of physiologic states meaning IVIM perfusion values can be easily quantified. Once scaled, the IVIM CBF of white matter and grey matter normocapnia and post-occlusion cortex on both hemispheres were strongly correlated to the reference standard.

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Mapping Brain Neurochemical and Functional Coupling Using Dynamic SPICE
Rong Guo1,2, Yudu Li1,2, Yibo Zhao1,2, Yao Li3, and Zhi-Pei Liang1,2

1Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China

Neuronal metabolite (e.g., glutamate, GABA) concentrations in the brain are known to be correlated with neural activity. Currently, fMRS is the primary tool for measuring neurochemical changes in response to brain activity. However, fMRS has several major practical limitations, including low spatial resolution, low SNR, and very limited brain coverage. In this work, a new dynamic 1H-MRSI technique is used to address these difficulties. This technique can map dynamic metabolic changes from the whole brain at high spatial and temporal resolutions. In addition, it can simultaneously acquire fMRI images to track brain functional activity during the scan. With this unique capability, we have carried out functional MRSI experiments with motor tasks to investigate the coupling between neural metabolism and neural activity. The experimental results clearly show an increase in Glx in the motor cortex during the motor activation.   

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Quantitative functional imaging of visual cortex activity in humans using multi-parametric blood oxygenation level dependent MRI
Christine Preibisch1,2,3, Stella Koutsouli1, Stephan Kaczmarz1,4, Samira Epp1, and Valentin Riedl1,2

1Neuroradiology, Technische Universität München, Munich, Germany, 2TUM-NIC, Technische Universität München, Munich, Germany, 3Clinic for Neurology, Technische Universität München, Munich, Germany, 4MRRC, Yale University, New Haven, CT, United States

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is widely used to assess local neuronal activity. However, the absolute metabolic demand related to BOLD-signal change is still largely unknown. In the current study we investigated the feasibility of multi-parametric quantitative BOLD (mq-BOLD) measurements to detect changes in tissue oxygenation in healthy, cortical gray matter during different states of visual stimulation. Our results show that mq-BOLD measurements are well feasible for standard activation paradigms. However, subject motion and transient states of brain activation might impact on quantitative parameter mapping due to longer acquisition times.

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Dysfunction of functional connectivity between default mode network and cerebellar structures in patients with mTBI in acute stage. rsfMRI and DTI study.
Maxim Ublinskiy1,2, Natalia Semenova1,2, Tolib Akhadov1, Andrei Manzhurtsev2, Petr Menshchikov3, and Dmitriy Kupriyanov4

1Clinical and Research Institute of Emergency Pediatric Surgery and Trauma, Moscow, Russian Federation, 2Institute of Biochemical Physics Russian Academy of Sciences, Moscow, Russian Federation, 3Semenov institute of Chemical Physics of Russian Academy of Sciences, Moscow, Russian Federation, 4Philips Healthcare Russian Federation, Moscow, Russian Federation

The revealed changes in DMN neuronal connection and cerebellar regions in acute stage of mTBI patients can be an initial step of damages leading to cognitive deficit which can be developed in future in long-term period of injury. We suggest that further research in this direction will demonstrate whether DMN functional integrity analysis can serve as a biomarker for monitoring the recovery of patients with mTBI.

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Towards a more precise and comprehensive characterization of the relationship between EEG alpha rhythm and thalamic BOLD signal
SeyedMohammad Shams1,2, Pierre LeVan3, and J. Jean Chen1,2

1Rotman Research Institute at Baycrest, North York, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Department of Radiology, University Medical Center Freiburg, Freiburg, Germany

In this study, the relationship between EEG alpha band power and the BOLD signal is examined in the thalamus. We overcome previous limitations in temporal resolution by using fast fMRI (MREG) acquisitions. We also consider a wider range of lags between EEG and BOLD signals than previous studies. In addition, cross correlations between alpha EEG and fMRI signals from all voxels in the thalamus region of all subjects are automatically classified using clustering to reveal consistent spatial-temporal patterns in the relationships between EEG alpha activity and BOLD signals in different parts of thalamus.

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Connectivity in the Default Mode Network of Schizophrenic Patients Investigated with Microstates and mGluR5 Receptor Availability Using Simultaneously Recorded Trimodal ([11C]ABP688-PET/MR/EEG) Imaging
Ravichandran Rajkumar1,2,3, Claudia Régio Brambilla1,2,3, Joshua Bierbrier1,4, Shukti Ramkiran1,2, Linda Orth1,2, Andrej Ruch2, Andreas Matusch5, Markus Lang6, Lutz Tellmann1, Ezequiel Farrher1, Jörg Mauler1, Elena Rota Kops1, Jürgen Scheins1, Bernd Neumaier6, Johannes Ermert6, Hans Herzog1, Karl-Josef Langen1,3,7, Christoph Lerche1, N. Jon Shah1,3,8,9, and Irene Neuner1,2,3

1Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany, 2Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany, 3JARA - BRAIN - Translational Medicine, Jülich, Aachen, Germany, 4Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada, 5Institute of Neuroscience and Medicine 2, INM-2, Forschungszentrum Jülich, Jülich, Germany, 6Institute of Neuroscience and Medicine 5, INM-5, Forschungszentrum Jülich, Jülich, Germany, 7Department of Nuclear Medicine, RWTH Aachen University, Aachen, Germany, 8Institute of Neuroscience and Medicine 11, INM-11, Forschungszentrum Jülich, Jülich, Germany, 9Department of Neurology, RWTH Aachen University, Aachen, Germany

This exploratory study aims at underpinning the relationship between functional connectivity (fMRI), microstates (EEG) and glutamatergic receptor (mGluR5) availability ([11C]ABP688-PET) in healthy controls (HC) and schizophrenic (SZ) patients using simultaneously acquired trimodal (PET/MR/EEG) data.  The single modality results show hyperactivity in vDMN regions of SZ patients (fMRI), a significant decrease in volume of distribution (Vt) of SZ patients (non-smoker group), and increased microstate global field power (GFP) in SZ patients. Correlations between Vt and GFP did not reveal any significant results, but the trend suggests a strong influence of smoking status and its association with global reductions in mGluR5 availability.

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Detection of oscillatory event-related visual potentials and BOLD signals using interleaved simultaneous multi-slice inverse imaging and electroencephalography
Shu-Yu Huang1, Yi-Tien Li1,2, Ying-Hua Chu1, Kevin Wen-Kai Tsai1, Guan-Yi Lu1, Wen-Jui Kuo3, and Fa-Hsuan Lin1,4,5

1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 2Department of medical imaging, Taipei Medical University – Shuang Ho Hospital, New Taipei City, Taiwan, 3Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan, 4Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland, 5Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada

We propose to interleave simultaneous multi-slice inverse imaging (SMS-InI) concurrently with EEG. In this way, EEG recorded with gradient-artifact-free intervals (1.9 s in every 2-s) is expected to have high quality, while SMS-InI provides comparable sensitivity and spatiotemporal resolution like EPI. We used SMS-InI-EEG to measure 15-Hz steady-state visual evoked potentials comparable with EEG recorded outside MRI and the hemodynamic responses comparable with EPI.  

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Correspondence between structure and function in the human brain using data from over 15,000 individuals
Na Luo1,2, Jing Sui1,2,3, Jessica A. Turner4, Zening Fu3, Anees Abrol3,5, Eswar Damaraju3, Jiayu Chen3, Dongdong Lin3, David C. Glahn6, Amanda L. Rodrigue6, and Vince D. Calhoun3,5,6

1Brainnetome Center and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China, 2University of Chinese Academy of Sciences, Beijing, China, 3The Mind Research Network, Albuquerque, NM, United States, 4Department of Psychology, Neuroscience Institute, Georgia State University, Atlanta, GA, United States, 5Department of Electrical and Computer Engineering, the University of New Mexico, Albuquerque, NM, United States, 6Department of Psychiatry, Yale University, School of Medicine, New Haven, CT, United States

This study compared the structural-functional correspondence on a large discovery dataset (7104 functional scans, 6005 structural scans) and a replication dataset (9214 subjects). Independent component analysis was applied to identify structural and functional networks. Spatial correlation was then computed using Pearson correlation and mutual information. Results indicated that 1) 24 replicated pairs were identified showing high structural-functional correspondence; 2) the structural-functional correspondence showed the following hierarchy: Basal ganglia > Somatomotor, Visual > DMN, Temporal, Cerebellum > Frontal and Parietal domains; 3) replicated results allowing us to provide evidence of a stable template of structural-functional correspondence for the public to use.

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On the variability of cardiac pulse artifacts across heartbeats affecting EEG recordings in simultaneous EEG-fMRI: a 7T study
João Jorge1, Charlotte Bouloc1, Lucie Bréchet1,2, Christoph M. Michel2,3, and Rolf Gruetter1,4,5

1Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Functional Brain Mapping Lab, University of Geneva, Geneva, Switzerland, 3Biomedical Imaging Research Center (CIBM), Lausanne and Geneva, Switzerland, 4Department of Radiology, University of Lausanne, Lausanne, Switzerland, 5Department of Radiology, University of Geneva, Geneva, Switzerland

EEG recordings performed in MRI scanners suffer from complex artifacts caused by heart function, termed pulse artifacts (PAs), which can strongly compromise EEG quality. This study investigated the properties and mechanisms of PA variability across heartbeats, which remains poorly understood. Simultaneous EEG-fMRI was performed at 7T on healthy participants with concurrent breathing and cardiac recordings. PA variability showed an important impact on EEG quality, and was linked not only to changes in head position/orientation across time, but also, and more importantly, to respiration and heart rate. These findings have important consequences for PA correction, highly relevant to most EEG-fMRI applications.

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The Relationship between Local Field Potential and Blood-oxygenation-level Dependent Signal Can Be Nonlinear
Xiaodi Zhang1, Wen-Ju Pan1, and Shella Keilholz1

1Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States

Many studies that involve simultaneous local field potential (LFP) and blood-oxygenation-level dependent (BOLD) signal measurements use correlation analysis, which assumes a linear relationship between the two. To experimentally determine whether the relationship is linear, we obtained a LFP vs BOLD response curve from simultaneous LFP and BOLD measurements. The relationship between the two was nonlinear under isoflurane but not under dexmedetomidine, which suggests that correlation may not always correctly capture the relationship between LFPs and BOLD.

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Divergent structural and functional changes across brain hierarchy account for population variation in demographics and behavior
Feng Han1 and Xiao Liu1,2

1Biomedical Engineering, Pennsylvania State University, State College, PA, United States, 2Institute for Cyber Science, Pennsylvania State University, State College, PA, United States

A robust link was recently established between resting-state functional connectivity and human behavioral measures. To understand the structural basis underlying this relationship, we examined the population covariation of the cortical thickness, resting-state connectivity, and a set of demographic and behavioral measures. We found that divergent changes at the lower- and higher-order brain regions in the cortical thickness and resting-state connectivity are structural and functional imaging features that are most tightly linked to the population behavioral variation. The findings suggest that differentiated changes across brain hierarchy could be important to brain function.

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Rhythmic EEG inputs modulate the thalamocortical network in epilepsy
Yun Qin1, Zhiliang Li1, Tao Zhang1, Cheng Luo1, and Dezhong Yao1

1University of Electronic Science and Technology of China, Chengdu, China

Thalamus has the capacity to generate oscillations characterized by different frequency and levels of synchrony. However, little is known of what function the generated EEG dynamic pattern may serve in thalamocortical interactions. In this study, we used psychophysiological interaction framework to detect fMRI thalamocortical coupling modulated by dynamic EEG connectivity patterns, and tested the alteration of the modulatory couplings in juvenile myoclonic epilepsy. The results found frequency-dependent characteristics for the thalamocortical coupling. The group comparison revealed the couplings were altered with certain thalamus sets involved in JME, which may have implications for better understanding of the thalamocortical circuit influenced by epileptic activity.

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Classification of BOLD-fMRI dynamic functional connectivity states based on simultaneous EEG microstates
Rodolfo Abreu1,2, Alberto Leal3, and Patrícia Figueiredo1

1ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Ténico, Universidade de Lisboa, Lisboa, Portugal, 2Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT) and CNC.IBILI, University of Coimbra, Coimbra, Portugal, 3Department of Neurophysiology, Centro Hospitalar Psiquiátrico de Lisboa, Lisboa, Portugal

Dynamic functional connectivity (dFC) states have been identified in BOLD-fMRI data, but their electrophysiological underpinnings remain a matter of debate. The simultaneous acquisition of the EEG has previously allowed the identification of EEG signatures of dFC states. Here, we further investigated whether EEG microstates can be used to classify dFC states. We found that highly accurate classification could be achieved based on the three EEG microstates with the highest global explained variance, in simultaneous EEG-fMRI data acquired from eight epileptic patients. These results further support the electrophysiological underpinnings of fMRI dFC states, highlighting their relationship with EEG-derived microstates.

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Adipose Tissue Evaluation in Economic Fish with MRI Imaging Translation via Conditional Generative Adversarial Networks
rui nian1,2, shuang kong1, shichang zhang*1, xiaoyu li1, and qiang yuan1

1Ocean University of China, qingdao, China, 2Radiology Department,Bosto Children's Hospital; and Harvard Medical School, Boston, MA, United States

High presence of excess fat makes strong implications in obesity and its complications. High-fat diet could trigger fat accumulation. In this paper, we investigated and developed one quantitative online assessment strategy for adipose tissues in economic fish with Conditional Generative Adversarial Networks (CGAN) by means of magnetic resonance imaging (MRI), which could automatically help insights into the morphology of the adipose tissues in fish.

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BOLD Representation of Canonical EEG Microstates
Obada Al Zoubi1,2, Ahmad Mayeli1,2, Masaya Misaki1, Vadim Zotev1, Aki Tsuchiyagaito1,3, Jared Smith1, Hazem Refai2, Martin Paulus1, and Jerzy Bodurka1,4

1Laureate Institute for Brain Research, Tulsa, OK, United States, 2Electrical and Computer Engineering, University of Oklahoma, Norman, OK, United States, 3Japan Society for the Promotion of Science, Tokyo, Japan, 4Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, United States

We extracted the topographical similarity of EEG signals with four canonical EEG microstate (EEG-ms, A through D) templates from 47 healthy subjects. Then, a general linear model (GLM) examined topographical similarities using time courses convolved with hemodynamic response function (HRF) as regressors of interest for individual subjects. A one-sample t-test was applied on the regression coefficients to identify brain regions whose BOLD activity is related to EEG microstate time courses, with significant results reported using a cluster size correction.  

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Evaluation of a flexible polyimide-based microelectrode array for MR-compatibility and recording performance in 7T research system
Xiao Yu1,2, Bo-Wei Chen3, Boyi Qu1,4, Tingting He1, You-Yin Chen3, and Hsin-Yi Lai1,5

1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China, 2Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, China, 3Department of Biomedical Engineering, National Yang Ming University, Taiwan, China, 4College of Biomedical Engineering & Instrument Science,Zhejiang University, Hangzhou, China, 5The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China

For simultaneous recording of spike signal and functional magnetic resonance imaging (fMRI) response, both MR-compatibility and performance of electrophysiological signal acquisition of the electrode matters. Previously, we have designed a flexible polyimide-based microelectrode array which has good biocompatibility, as well as high and stable signal-to-noise ratio for chronic recording. This study evaluated the MR-compatibility and recording performance of microelectrode array in the 7T research system (Siemens, Erlangen, Germany). The results suggest that it has the potential to facilitate simultaneous spike-recording during MR scanning in 7T.

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Line Scanning fMRI combined with optical calcium recordings to resolve the direct BOLD response to underlying slow oscillation-associated traveling waves
Dirk Cleppien1, Felipe Aedo-Jury1, Miriam Schwalm1, Nuse Afahaene1, and Albrecht Stroh1

1AG Molecular Imaging and Optogenetics of the Institute of Pathophysiology, University Medical School of Johannes Gutenberg-University Mainz, Mainz, Germany

In this multimodal approach consisting of line scanning (ls)-fMRI combined with optical calcium recordings, we investigated the direct BOLD response on a sensory stimulus in the slow wave brain state in anesthetized rats. We were able to observe the fMRI correlate of a slow wave recruiting the field of view with a significant latency between the recruitment of posterior and anterior voxels. This latency suggest the identification of the propagation of slow waves, as described with optical methods.

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Optogenetic fMRI of large-scale vestibular system and their cross-modal functions
Alex T. L. Leong1,2, Yong Gu3, Xunda Wang1,2, Russell W. Chan1,2, Ying-Shing Chan4, and Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, 3Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China, 4School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China

The vestibular system - pivotal for our sense of balance and orientation - integrates input from our other dominant senses, such as audition and vision, to create a multisensory percept. However, little is known regarding the extent of modulatory effects (if any) that the vestibular system exerts on the other sensory processing. Here, our report combined fMRI, optogenetics and sensory stimuli to provide large-scale brain-wide insights into the extent of cross-modal modulatory effects of the vestibular system on sensory processing. We reveal that vestibular nucleus optogenetic stimulation can modulate auditory and visual sensory processing at midbrain, thalamic and cortical regions.

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Optogenetically-evoked spindle-like activity from thalamus propagates brain-wide and enhances rsfMRI connectivity
Xunda Wang1,2, Alex T. L. Leong1,2, Shuai Guo1,2, Celia M. Dong1,2, and Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China

Hierarchical nesting of spindles and slow oscillations have been identified as a unique characteristic for long-range functional neural integrations in thalamo-cortical network. Meanwhile, low spontaneous oscillatory neural activities are proposed to constrain and elicit resting state fMRI connectivity. Yet, the brain-wide spindle-related BOLD activity and the contribution of thalamic spindle-like activity to brain-wide rsfMRI connectivity remain largely unknown. We demonstrate for the first time that the spindle-like optogenetic stimulation at the somatosensory thalamus can evoke robust BOLD activations brain-wide and influence brain-wide rsfMRI connectivity. Our work suggests that interaction between spindles and slow oscillations is important for maintain rsfMRI connectivity. 

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Towards artefact-free awake rat brain fMRI/EEG studies with multiband-SWIFT fMRI
Jaakko Paasonen1, Hanne Laakso1, Tiina Pirttimäki1, Petteri Stenroos1, Lauri Lehto2, Michael Garwood2, Shalom Michaeli2, Djaudat Idiyatullin2, Silvia Mangia2, and Olli Gröhn1

1A.I.V. Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

EPI sequence is the most common choice for fMRI investigations. EPI, however, is loud for awake studies, prone to susceptibility-induced artefacts, and sensitive to motion. Therefore, we investigated whether the unique features of MB-SWIFT would make it a potential alternative for EPI to overcome these issues. Our results suggest that MB-SWIFT is dramatically more silent compared to EPI, body movement does not affect the voxels in brain, gradient-switching artefacts are minimal in electrophysiological data, and good quality resting-state fMRI data can be obtained from awake rats. We conclude that MB-SWIFT is an advantageous alternative to EPI in demanding experimental applications.

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Long-term effect of isoflurane anesthesia on functional connectivity detected by fMRI and local field potential measurements
Petteri Stenroos1, Tiina Pirttimäki1, Jaakko Paasonen1, Raimo A. Salo1, Ekaterina Zhurakovskaya1, Heikki Tanila1, and Olli Gröhn1

1A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland

Isoflurane, a commonly used anesthetic in preclinical studies, is known to alter functional connectivity during anesthesia. It has been found that isoflurane can induce brain plasticity and cause long-term changes on brain function. Therefore, we studied the connectivity changes caused by single isoflurane (3h, 1.8%) exposure after a one-month waiting period by resting state fMRI and local field potential (LFP) measurements. Treated rats exhibited significantly strengthened connectivity between hippocampus and somatosensory cortex both in fMRI and LFP, indicating long-term modulation of brain activity by single administration of isoflurane anesthesia compared to non-treated controls.


fMRI Contrast Mechanisms & Signal Characteristics

Exhibition Hall
Wednesday 13:30 - 14:30
 fMRI

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Blocking AQP4 channels impacts BOLD fMRI but not Diffusion fMRI response patterns induced by visual stimulation
Yuji Komaki1, Clément Debacker1, Boucif Djemai1, Luisa Ciobanu1, Tomokazu Tsurugizawa1, and Denis Le Bihan1

1NeuroSpin, CEA, Saclay, France

We compared BOLD and Diffusion fMRI mouse brain maps obtained through visual stimulation before and after TGN-020 administration, an AQP4 receptor antagonist and astrocyte swelling inhibitor. Activations were observed in the primary visual cortex and the superior colliculus with both methods. BOLD signal changes were significantly increased after AQP4 inhibition, while the DfMRI signals were not affected. These results suggest that the DfMRI signal does not originate from astrocyte swelling.

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Hemodynamic response of white matter to event-related functional tasks
Muwei Li1, Zhaohua Ding1, and John C. Gore1

1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States

There is increasing evidence that white matter (WM) elicits robust blood oxygenation level-dependent (BOLD) responses to task in functional MRI. However, the detection of BOLD signals in WM has usually assumed a canonical hemodynamic response function (HRF) as in gray matter (GM), which contributes to low sensitivity in detection of WM activation. We demonstrate in this work that the HRFs in WM possess reduced magnitudes, delayed onsets and prolonged initial dips in WM tracts that are connected with task activated GM, thus calling for alternate data analyses in exploring WM activity.

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Improved Selection of Hemodynamic Response Function in ASL Based Perfusion fMRI
Qingfei Luo1, Wen-Ming Luh2, and Jerzy Bodurka1,3

1Laureate Institute for Brain Research, Tulsa, OK, United States, 2Cornell MRI Facility, Cornell University, Ithaca, NY, United States, 3Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, United States

Two types of hemodynamic response function (HRF) are used in the data analysis of ASL based perfusion fMRI (ASL-fMRI): single gamma function (1-gamma) and the sum of two gamma functions (2-gamma). This study aims to optimize the selection of HRF by comparing the performances of standard 1-gamma and 2-gamma HRFs and also a modified 2-gamma HRF, which has earlier response peak time than the standard one. Our visual ASL-fMRI experiment indicate that the modified 2-gamma provides the best detection sensitivity and we recommend to use it in ASL-fMRI.

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The role of perivascular spaces in white matter blood oxygenation level dependent MRI
Jonathan Doucette1,2, Laura Kim1,2, Enedino Hernández-Torres1,3, Friedrich Anastasopoulos4, Christian Kames1,2, and Alexander Rauscher1,3,5

1UBC MRI Research Centre, Vancouver, BC, Canada, 2Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, 3Pediatrics, University of British Columbia, Vancouver, BC, Canada, 4Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 5Division of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada

Using vascular parameters obtained from dynamic susceptibility contrast MRI, the gradient echo and spin echo blood oxygenation level dependent (BOLD) signals were simulated at 3 and 7T in order to investigate the effects of tissue orientation and perivascular spaces. We show that both the magnitude and the tissue orientation dependence of the BOLD effect is amplified by perivascular spaces.

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Electrical Properties Tomography based Functional Magnetic Resonance Imaging (EPT-fMRI)
Michael Helle1 and Ulrich Katscher1

1Philips Research, Hamburg, Germany

This study presents a new approach for the assessment of functional brain areas by using Electrical Properties Tomography (EPT). The measurements are performed similarly to conventional fMRI experiments to investigate brain activation for primary motor cortex areas, whereas EPT maps are generated for activation and resting periods and compared to BOLD fMRI images.

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Cortical depth- and feature-dependent intrinsic functional connectivity in human visual and auditory cortices
Pu-Yeh Wu1, Hsin-Ju Lee1,2, Jyrki Ahveninen3, Jonathan R Polimeni3, Hesheng Liu3, Wen-Jui Kuo2, and Fa-Hsuan Lin1,4,5

1National Taiwan University, Taipei, Taiwan, 2National Yang-Ming University, Taipei, Taiwan, 3Department of Radiology, Harvard Medical School - Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 4Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 5Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland

This study reveals the tonotopy- and retinotopy-dependent intrinsic functional connectivity (iFC) across cortical depths in the human auditory and visual cortieces, respectively. Using 7T fMRI data with 1-mm isotripic resolution, we demonstrated that feature-dependent iFC have a higher selectivity in the primary sensory than in the secondary sensory area. The selectivity was generally higher as we moved from superficial to deep cortical depths, while the difference between the primary sensory and secondary sensory area was more prominent in the intermediate cortical depth.

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Correlation between inter-cortical depth hemodynamic responses and oscillatory neuronal responses during music listening
Pu-Yeh Wu1, Hsin-Ju Lee1,2, Hsiang-Yu Yu3, Cheng-Chia Lee4, Chien-Chen Chou3, Wen-Jui Kuo2, and Fa-Hsuan Lin1,5,6

1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 2National Yang-Ming University, Taipei, Taiwan, 3Neurology Department, Taipei Veterans General Hospital, Taipei, Taiwan, 4Department of Neurosurgery, Taipei Veterans General Hospital, Taipei, Taiwan, 5Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 6Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland

We explored the correlation between cortical depth-specific BOLD signal and oscillatory neuornal activity during music listening using high resolution fMRI data (3T with 1.5 mm isotropic resolution) and stereotactic electroencephalography.  Three findings are: first, the hemodynamic responses in human auditory cortex was significantly correlated with neuronal oscillation in high gamma band (40 Hz to 90 Hz). Second, the intermediate cortical depth was more closely related to neuronal oscillation. Third, the neuronal-hemodynamic correlation was higher in core than in noncore region.

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BOLD-fMRI Using a 3D Ultrafast Gradient-echo-based Sequence Using Quadratic-phase Encoding (RASE-II) in Comparison with 2D and 3D EPI
Ryu JaeKyun1,2, Jung Won Beom1,2, Son Jeong Pyo1,2, Kim Seong-Gi1,2, and Park Jang-Yeon1,2

1Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea, Republic of, 2Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of

We recently introduced a novel ultrafast 3D gradient-echo-based imaging technique using spatio-temporal encoding (SPEN) or quadratic-phase encoding, which were dubbed RASE-I and -II (Rapid Acquisition with Sequential Excitation). RASE has less sensitivity to field inhomogeneities and susceptibility differences compared to conventional gradient-echo EPI (GE-EPI), sharing the advantages of 3D imaging such as high signal-to-noise ratio and high spatial resolution. In this study, we present promising results of RASE-II fMRI, i.e., better t-scores, tSNR than conventional 2D and 3D GE-EPI, on a 9.4-T animal scanner.

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Laminar fMRI with T2-prepared multi-echo FLASH
Viktor Pfaffenrot1,2 and Peter J. Koopmans 1,2

1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany, 2High Field and Hybrid MR Imaging, University Hospital Essen, University of Duisburg-Essen, Essen, Germany

Examining signal changes at the level of cortical layers using T2*-weighted fMRI suffers from a systematic bias caused by extravascular effects of draining veins. T2-weighting promises higher specificity to signal changes near the origin of neural activity. In this work, we use a T2-prepared, multi-echo FLASH sequence at 7 T in a flickering checkerboard experiment targeting the visual cortex to investigate the feasibility of this sequence for laminar fMRI. The layer profiles indicate the desired T2-weighted response in grey matter, but also a peak at the pial surface likely caused by intravascular effects in the pial veins.

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fMRI signal oscillations in rats can be induced by electric paw stimulation but do not deteriorate the observed BOLD peak
Henriette Lambers1, Lydia Wachsmuth1, Franziska Albers1, Martin Segeroth1, and Cornelius Faber1

1Translational Research Imaging Center (TRIC), University Hospital Muenster, Muenster, Germany

Signal time courses of BOLD fMRI measurements in rodents often show a damped oscillation which may superimpose with the expected hemodynamic response. In order to explore and characterize these oscillations, we performed EPI-BOLD measurements with high temporal resolution upon electrical paw stimulation. 55 % of the measurements showed oscillations with a frequency of 0.2 Hz. We could verify that these oscillations were induced by stimulation but did not affect the BOLD response. Consequently, hemodynamic response function models for statistical analysis are valid independently from the occurrence of oscillations.

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Longitudinal study of BOLD HRF in human cortex
Amanda J Taylor1, Xiaowei Zou2, Jung Hwan Kim2, and David Ress2

1Neuroscience, Baylor College of Medicine, Houston, TX, United States, 2Baylor College of Medicine, Houston, TX, United States

A simple audiovisual stimulus combined with a fast-paced task evoked a strong HRF across a majority of cerebral cortex during four scanning sessions to measure the repeatability of BOLD over time. HRFs were characterized by spatial and temporal parameters and showed remarkable correlation across the time points, which spanned three hours, three days, and three months. Results showed that HRFs are repeatable for consistent quantification of neurovascular coupling.

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R1 and R2 characterization of human blood with phase-cycled balanced steady-state free precession (bSSFP)
Marlon Pérez-Rodas1,2, Hildegard Schulz1, Rolf Pohmann1, Klaus Scheffler1,3, and Rahel Heule1

1High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Graduate Training Centre of Neuroscience, IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany, 3Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany

Balanced steady-state free precession (bSSFP) sequences have received increased interest for functional BOLD experiments since, in contrast to conventional EPI-based techniques, they are not prone to geometric distortions in the phase encoding direction. Characterization of measured BOLD signal changes requires consideration of extravascular as well as intravascular contributions. Knowledge about the relaxation rates of human blood is a prerequisite to quantify the intravascular contribution to the BOLD effect. Here, R1 and R2 relaxation rates of blood samples are intrinsically obtained from a series of phase-cycled bSSFP scans to account for the repetition time dependence of R2 due to rapid refocusing.

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Revisiting mental chronometry with isotropic resolution and full brain coverage.
Zahra Fazal1, Samantha Noteboom1, Daniel. G. Gomez1, Jose. P. Marques1, and David. G. Norris1,2

1Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany

In this project, we are using a multiband echo-shifted EPI sequence for TR less than 160 ms combined with a novel analysis approach to measure interregional BOLD onset times from a visual-motor association task with full brain coverage and isotropic resolution. 

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Voxel-Specific Modeling of Physiological Fluctuations in BOLD fMRI Signal
Rong-Wen Tain1, Shauna M. Stark1, Samantha Rutledge1, David B. Keator1, and Craig E.L. Stark1

1University of California, Irvine, CA, United States

Cardiac pulsation and respiration have significant contributions to the BOLD signal. This is particularly challenging given the long TRs typically used in BOLD experiments since these fluctuations are at higher frequency than the sampling rate and therefore aliased to lower frequency components. This study presents a new voxel-specific method accounting for the physiological effects in BOLD time series signal. We show that this approach is able to improve the estimation of physiological effects compared to the widely used RETROICOR method.

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Effects of Spinal Cord vascular geometry on the BOLD-fMRI contrast
Fabio Mangini1, Laura Maugeri1, Mauro DiNuzzo1, Marta Moraschi2, Daniele Mascali2, Alejandra Sierra3, Alessia Cedola4, Federico Giove2, and Michela Fratini1

1IRCCS Fondazione Santa Lucia, Rome, Italy, 2Centro Fermi-Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", Rome, Italy, 3A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 4CNR-Nanontec, c/o Dipartimento di Fisica, Rome, Italy

The effects of the spinal cord (SC) vessel topology on the blood oxygenation level dependent (BOLD) signal is poorly characterized. We performed numerical simulations on models of vasculature systems  based on the vascular network extracted from X ray tomographic images of a mouse SC. By taking into account the different vessels orientation of the SC, our results provides useful information to understand how the vascular distribution influences the BOLD contrast. 

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MP-PCA denoising to improve detection of task-based fMRI activation in brain tumor patients
Benjamin Ades-Aron1, Jelle Veraart1, Els Fieremans1, Dmitry Novikov1, and Timothy Shepherd1

1Radiology, Center for Biomedical Imaging, New York University School of Medicine, New York, NY, United States

Functional MRI improves preoperative planning in brain tumor patients, however BOLD signal changes for task-based 3T fMRI are only 2-4% and the tumor often compromises patient performance. This retrospective study evaluated Marchenko-Pastur Principle Component Analysis (MP-PCA) denoising to increase sensitivity for cortical regions recruited during language task-based fMRI paradigms in brain tumor patients. MP-PCA denoising is shown to improve the clinical value and practical utility of performing preoperative fMRI in brain tumor patients.  

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Dynamic Model-based Reconstruction for Oscillating Steady State fMRI
Amos A. Cao1, Shouchang Guo1, and Doug C. Noll1

1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States

We introduce Oscillating Steady State (OSS) fMRI, a method that uses quadratic phase cycling and balanced gradients to create an oscillating T2* sensitive signal. We also present a model-based reconstruction that converts these signal oscillations into B0 estimates, enabling correction for respiratory or scanner induced signal changes. OSS fMRI enables the SNR benefits of bSSFP-based methods, while adding T2* sensitivity and B0 encoding into a unique oscillating signal.

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Monte Carlo simulation of VASO fMRI from real microvascular angiograms of the mouse cortex
Élie Genois1, Louis Gagnon1, Sava Sakadžić2, Anna Devor2,3, David A. Boas4, and Michèle Desjardins1

1Université Laval, Quebec, QC, Canada, 2Massachussets General Hospital, Boston, MA, United States, 3University of California, San Diego, San Diego, CA, United States, 4Boston University, Boston, MA, United States

The vascular space occupancy (VASO) fMRI method probes changes in cerebral blood volume (CBV) but subsequent BOLD response contaminates the VASO signal reducing its SNR. Quantifying this BOLD contamination for different pulse-sequence parameters would improve our ability to measure CBV changes and optimize their quantification in a variety of physiological states and diseases. We have implemented a Monte Carlo method to model such effect from experimental cortical angiograms measured with two-photon microscopy on mice brains. Our results indicate that at 3T the BOLD contamination is relatively low (below 10%) but that this contamination is much higher at 7T and above.

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Comparing correlation between BOLD and susceptibility changes during Resting state and Task-based experiments
Sagar Buch1, Hacene Serrai1, and Ravi S Menon1,2

1Centre for Functional and Metabolic Mapping, Western University, London, ON, Canada, 2Medical Biophysics, Western University, London, ON, Canada

Quantitative susceptibility mapping (QSM) is a technique widely used for the measurement of venous oxygen saturation levels, through local deoxyhemoglobin concentration. In this work, QSM is used  to explore the relationship between magnetic susceptibility and BOLD signal changes during resting state and task based fMRI experiments, in order to better understand their cerebrovascular mechanisms. Negative correlations between susceptibility and BOLD signal were observed and evaluated for both resting state and task based experiments.

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Influence of multiband factor on temporal SNR limits using a clinical BOLD-EPI sequence
Pim Pullens1,2, Jasper Degryse3, Han Bossier3, Bieke Moerkerke3, Marcel Brass4, Guy Vingerhoets4, and Rik Achten2

1Department of Radiology, Ghent University Hospital, Gent, Belgium, 2Department of Diagnostic Sciences, Ghent University, Ghent, Belgium, 3Department of Data Analysis, Ghent University, Ghent, Belgium, 4Department of Experimental Psychology, Ghent University, Ghent, Belgium

Detectability of BOLD signal change is determined by temporal SNR (tSNR, mean divided by standard deviation of the signal over time), and ultimately determines how long needs to be scanned to obtain significant results in a fMRI experiment. With the clinical availability of multiband BOLD-EPI, TR can be shortened significantly, but it is unclear how MB factor influences tSNR. We show in a human subject that tSNR limits up to 192 can be reached and that multiple combinations of MB factor and voxel size can be used to reach similar tSNR values. 

3775
Computer 96
On the detection of resting-state correlations at high-frequencies under hyper- and hypo- capnic conditions
Kishore Vakamudi1, Khaled Talaat2, Arpad Zolyomi2, Arvind Caprihan3, and Stefan Posse1

1Neurology, University of New Mexico, Albuqueruque, NM, United States, 2University of New Mexico, Albuqueruque, NM, United States, 3Mind Research Network, Albuqueruque, NM, United States

In this study, we investigate the detection of resting-state fluctuations at higher frequencies using changes in global blood flow using hyper- and hypo- capnic conditions. A new adaptive TR approach enables higher sensitivity for detecting the resting-state fluctuations at higher frequencies through optimized TR that is tailored to the individual cardiac and respiratory rates. We were able to detect major resting-state networks (sensory motor, default-mode, and auditory) at frequencies between 0.45-0.8 Hz in normo-, hyper-, and hypo- capnic conditions.

3776
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The latency differentiates BOLD responses elicited by congruent and incongruent McGurk audio-visual stimulus pairs
Ren-Horng Wang1, Shu-Yu Huang1, Hsin-Ju Lee2,3, Wen-Jui Kuo3, and Fa-Hsuan Lin2,4,5

1Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 2National Taiwan University, Taipei, Taiwan, 3National Yang-Ming University, Taipei, Taiwan, 4Department of Mediacl Biophysics, University of Toronto, Toronto, ON, Canada, 5Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland

We used fast fMRI sampled at the 10-Hz rate to study fMRI timing in audiovisual integration. Using the McGurk protocol, we found that the superior temporal gyrus (STG) had significant BOLD time-to-half (TTH) difference between the McGurk and congruent audiovisual stimuli pairs. The significance of TTH difference between congruent and McGurk was progressively more significant from posterior to anterior regions (p-values at visual cortex, lateral occipital lob, occipital parietal junction, STG, and auditory cortex were 0.13, 0.12, 0.05, 0.02, and 0.01, respectively), suggesting that incongruent audio-visual stimuli cause more delayed the brain response at regions closer to primary auditory processing.

3777
Computer 98
Electrical conductivity as a potential mean to decouple the hemodynamic response from fMRI
Rita Schmidt1

1Neurobiology, Weizmann Institute of Science, Rehovot, Israel

MR electrical properties imaging offers new means for probing physiological information in-vivo. The interest for fMRI lies in the dependence of electrical conductivity on structural macroscopic changes and on ionic concentration changes. In-vivo electrical conductivity acquisition has the potential to provide the means to decouple the hemodynamic response from fMRI. Changes in electrical conductivity can be measured using phase changes in a spin-echo experiment. We compared BOLD fMRI with phase changes in SE-EPI using basic visual task paradigm at 3T MRI, which showed faster time response and more localized spatial activation. Further study is required to analyze possible contributing factors.        

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The lag structure by BOLD-based blood flow tracking indicates the partial non-neuronal source of resting state functional connectivity in mouse
Tomokazu Tsurugizawa1, Clement Debacker1, Boucif Djemai1, and Toshihiko Aso2

1NeuroSpin/CEA-Saclay, Gif-sur-Yvette, France, 2Department of Psychiatry, Kyoto University Graduate School of Medicine, Kyoto, Japan

A BOLD-based tracking technique was applied to 11 mice to investigate the cerebral circulation. Mapping of the phase of low-frequency component, which is called as “BOLD-based lag structure” showed the typical vascular structure as previous study. Interestingly, BOLD-based lag structure in bilateral somatosensory cortex was similar with the resting state functional connectivity between the bilateral somatosensory cortex. These results indicate the feasibility of this technique in mouse model. Furthermore, our results implies the partial contamination of circulating blood flow in resting state functional connectivity in mouse model.

3779
Computer 100
Drug cue-Induced brain response in protracted abstinence  and methadone maintenance measures for heroin addiction:  An event-related fMRI study
Xuan Wei1

1radiology department, Tangdu Hospital, the Fourth Military Medical University, Xi'an, China

 Our research aims to compare PA with MMT,to reveal which abstinence way is better to recover the brain function in heroin-dependent individuals.24 heroin-dependent patients under PA ,19 heroin-dependent patients under MMT and 20 healthy volunteers were recruited. The functional images were acquired by using a spin-echo EPI. In the last part of this study, we proved PA is closer to healthy group.This study showed that PA is more advantageous than MMT to reduce heroin addiction in drug cue-reactivity.


fMRI: Applications

Exhibition Hall
Wednesday 13:30 - 14:30
 fMRI

3780
Computer 101
fMRI of Radiologists with a Diagnosis Task
David J Ouellette1, Dan-Ling Hsu2, Eric van Staalduinen2, Syed Hussaini2, Sindhuja T. Govindarajan1, Patricia Stefancin2, and Tim Q Duong2

1Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 2Radiology, Stony Brook University, Stony Brook, NY, United States

Radiologists display superior perception in the analysis of medical images, but there are currently no fMRI studies of radiologists during a complex diagnosis task. In this study, radiologists read a variety of medical images and chose a diagnosis during fMRI. Compared to age- and education-matched controls, radiologists had lower functional activation in several visuospatial areas, including the lateral ocipital cortex and lingual gyrus.

3781
Computer 102
fMRI Mapping of Cognitive Brain Networks Involved in Perceptual Bias
Manyoel Lim1, Christopher O'Grady1,2,3, Mary Lynch4,5, Steven Beyea3,6,7,8, and Javeria Ali Hashmi1,7,9

1Brain Networks & Neurophysiology Lab, Halifax, NS, Canada, 2Department of Research, Nova Scotia Health Authority, Halifax, NS, Canada, 3Biomedical Translational Imaging Centre, Halifax, NS, Canada, 4Department of Anesthesia, pain management, and perioperative medicine, Dalhousie University, Halifax, NS, Canada, 5Pain Management Unit, QEII Health Sciences Centre, Halifax, NS, Canada, 6School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada, 7Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada, 8Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada, 9Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada

Prior expectations are critical in the formation of perceptions around phenomona such as pain. This study uses functional MRI to elucidate regions associated with both top-down and bottom-up aspects of pain perception, finding a network of higher-cortical regions for the former and primarily sensory regions for the latter. Additionally, bias towards cues rather than actual pain stimuli was both hypothesized and observed. The findings therefore shed light on the physiological basis of neural activation behind the complex and highly-biased formation of pain perceptions. 

3782
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Cerebral blood flow changes associated with meditation practice time: a longitudinal study
Zongpai Zhang1, Wenna Duan1, Steffi Chettiar1, Swanand A Wagh1, Wen-Ming Luh2, George Weinschenk1, and Weiying Dai1

1State University of New York at Binghamton, Binghamton, NY, United States, 2Cornell University, Ithaca, NY, United States

Longitudinal cerebral blood flow (CBF) images were acquired in ten college students after 2-month meditation practice. The CBF difference before and after meditation practice and the association between CBF change and meditation practice time were analyzed on a voxel-by-voxel basis using SPM8. We found significant perfusion increase and decrease in the occipital and thalamus regions respectively. However, the CBF increase and decrease in the corresponding regions exhibited negative and positive association with practice time respectively. Regional analysis confirmed that the direction of CBF change may switch after some amount of meditation practice time, indicating a complex neural pathway of meditation.

3783
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Engagement of multiple networks during meditation: an fMRI study
Vaibhav Tripathi1, Rahul Garg2, Vidur Mahajan3, and Anju Dhawan4

1Indraprastha Institute of Information Technology, New Delhi, India, 2Indian Institute of Technology, New Delhi, India, 3Centre for Advanced Research in Imaging, Neuroscience and Genomics, Mahajan Imaging, New Delhi, India, 4All India Institute of Medical Sciences, New Delhi, India

Long-term effects of meditation and the differences between meditators and non-meditators have been studied extensively. In order to understand the corresponding mechanisms of action, brain areas activated while meditating need to be studied. Such studies are limited due to lack of a suitable experimental paradigm and analysis technique. We investigated experienced meditators who underwent a 20 minutes audio-guided meditation in the fMRI scanner. Using the Intersubject correlation (ISC) analysis, correlated activity across the subjects was found in frontal pole, middle frontal gyrus, precuneus, primary somatosensory cortex, visual cortex, lingual gyrus, and cerebellum.

3784
Computer 105
Effects of eleven-week aerobic exercises on working memory of deaf children estimated using task state functional magnetic resonance imaging
Hang Qu1, Wang Wei1, and Weiqiang Dou2

1radiology department, AFFILIATED HOSPITAL OF YANGZHOU UNIVERSITY, YANGZHOU, China, 2MR Research China, Beijing, GE Healthcare, Beijing, China

In this study, we used a combined aerobic exercise and task functional magnetic resonance imaging (fMRI) on deaf children for eleven weeks to investigate the alternation of working memory function after exercise. The classic 2-back task included make odd-even judgment and short-term memory. The experimental group showed a significant improvement in the 2-back task performance and alternation of functional activity in temporal lobe, precuneus temporal lobe and precuneus. These findings may help to explain the synaptic plasticity of brain.

3785
Computer 106
Dual-route mechanism for pictorial visual perception in developmental dyslexia
Sunita Gudwani1, S.Senthil Kumaran1, Rajesh Sagar2, Madhuri Behari3, Manju Mehta4, Vaishna Narang5, SN Dwivedi6, and NR Jagannathan1

1Department of NMR and MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 2Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India, 3Department of Neurology, Fortis Hospital, New Delhi, India, 4Department of Psychiatry (Psychology Unit), All India Institute of Medical Sciences, New Delhi, India, 5Department of Linguistics, School of Language, Jawahar Lal Nehru University, New Delhi, India, 6Department of Biostatistics, All India Institute of Medical Sciences, New Delhi, India

Reading a window to world’s information, is a coordinated skill of grapheme-phoneme interface (letter-sound) at symbolic level. Inefficient mapping of this alphabets-horizontal string is labeled as dyslexia (reading problem). It can be developmental or acquired (post-stroke) disorder. Developmental dyslexia (DD) is heterogeneous state with disputed underlying mechanism(s) constraining optimal remediation. Compared to typical readers, DD literature is bifurcated into children with strength and impairment for visual perception. To unfold it neurobiologically, nonsymbolic visual processing role was studied. Observed bilateral brain activation (functional MRI) of ventral stream (inferior occipital and fusiform) and modified dorsal route-gating for figure-ground filtering in DD. 

3786
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Subcortical and cortical fMRI assessment of auditory pathway function associated with lifetime noise exposure in normally hearing listeners
Rebecca Susan Dewey1,2,3, Susan T Francis1, Hannah Guest4, Garreth Prendergast4, Rebecca E Millman4,5, Christopher J Plack4,5,6, and Deborah A Hall2,3,7

1Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 2NIHR Nottingham Biomedical Research Centre, Nottingham, United Kingdom, 3Hearing Sciences, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, United Kingdom, 4Manchester Centre for Audiology and Deafness (ManCAD), University of Manchester, Manchester, United Kingdom, 5NIHR Manchester Biomedical Research Centre, Manchester, United Kingdom, 6Department of Psychology, Lancaster University, Lancaster, United Kingdom, 7University of Nottingham Malaysia, Jalan Broga, Selangor Darul Ehsan, Malaysia

We investigated the relationship of lifetime noise exposure with subcortical and cortical auditory fMRI BOLD responses to broadband noise in 62 individuals with clinically normal audiometric thresholds. We demonstrate robust individual and group responses to a broadband noise across structures in the auditory pathway. In line with animal models, we show a significantly increased BOLD response to stimulus onset in individuals with high noise exposure compared to those with low noise exposure in all auditory structures assessed. We also show a trend towards individuals with high noise exposure exhibiting a greater sustained BOLD response.

3787
Computer 108
7T functioanl MRI reveals frequency-dependent responses during vibrotactile stimulation at somatosensory cortex
Boyi Qu1,2, Xiao Yu1,3, Kaiyue Wang1,2, Mengjie Xin1, and Hsin-Yi Lai2,4

1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China, 2College of Biomedical Engineering & Instrument Science,Zhejiang University, Hangzhou, China, 3Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, China, 4The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China

To investigate whether the brain can directly encode different vibrotactile frequencies, we made a MR-compatible lab-designed vibrotactilestimulator to presented pulse stimuli on middle finger (with a frequency difference in the same duration) andusing BOLD fMRI to explore the effectsofvibrotactilefrequencyin somatosensory cortex with 7T MR research system. The results showedthat the lab-designed MR compatible vibrotactile stimulator could elicit BOLD responsesin the somatosensory cortex. Also, the BOLD response was frequency-dependent with the peak at 6Hz.

3788
Computer 109
Effect of cue induced craving on brain morphometry and function in adolescent inhalant users
Shobhit Jain1, S Senthil Kumaran2, Anju Dhawan1, Raman Deep Pattanayak 1, and Raka Jain3

1Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India, 2Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 3National Drug Dependence Treatment Centre, All India Institute of Medical Sciences, New Delhi, India

Inhalants are legal, inexpensive substances that are often abused by adolescents. This study compared the BOLD changes in brain associated with cue-induced craving in adolescent inhalant users (n=13) and healthy controls (n=12)  to elucidate the neural mechanisms associated with cue-induced craving. The cases exhibited an increased activation of superior occipital gyrus, inferior parietal lobule, cingulate gyrus, thalamus, and culmen and a decreased activation of insula as compared to control group for craving cues. Visual cue reactivity was associated with activation of the areas responsible for visual perception, visuo-spatial attention and working memory, control and motivation.

3789
Computer 110
The faster the better: onsets of pre-SMA and right inferior frontal activations predict successful stopping in a stop-signal task
Hsin-Ju Lee1,2, Fa-Hsuan Lin3,4, and Wen-Jui Kuo2

1National Taiwan University, Taipei, Taiwan, 2National Yang-Ming University, Taipei, Taiwan, 3University of Toronto, Toronto, ON, Canada, 4Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland

Using fast fMRI (whole-brain 10 Hz sampling), we revealed BOLD activities in the pre-SMA and right inferior frontal gyrus are activated faster for successful than for unsuccessful stopping.


3790
Computer 111
Dopaminergic modulation of reasoning ability in non-demented Parkinson’s disease
Xiuqin Jia1, Tao Jiang1, Zihao Zhang1, Kun Li1, and Peipeng Liang2

1Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China, 2School of Psychology, Capital Normal University, Beijing, China

Patients with Parkinson's disease (PD) are more likely to suffer cognitive decline and experience difficulties in daily living requiring reasoning including medication use, financial management, and nutrition and food preparation even at early stage of the disease.1,2 The present study aimed to explore L-dopa modulation on the reasoning ability in PD. Twenty non-demented PD underwent reasoning fMRI examinations OFF-medication and ON-medication. It was found that ON-medication PD patients exhibited improved reasoning performance and recruited the striatum compared to OFF-medication. The current findings suggest that L-dopa treatment mediated the neural activity in the striatum and further improved the behavior performance.

3791
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Brain-to-Brain Interaction and Entanglement
Ray Lee1

1Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NJ, United States

      Recognizing that the coherence of proton nuclear spin ensembles in dyadic brains is periodically enforced by the RF excitation pulses so that superposition states may be embedded in MR signals, the mathematical language of quantum theory is utilized to describe a dyadic fMRI experiment. Within this platform, the data-driven dyadic communication model, two coupled three-layer neural networks, predicts not only brain-to-brain interaction operations but also entanglement operations which might profoundly expand our understanding of human social communication. 

3792
Computer 113
Neurocognitive modifications associated with auditory perception in children and adolescent group in early and late blind subjects: A functional magnetic resonance imaging study
Ankeeta Ankeeta1, S Senthil Kumaran2, N R Jagannathan2, and Rohit Saxena2

1Neurology, All India Institute of Medical Sciences, New Delhi, India, 2All India Institute of Medical Sciences, New Delhi, India

Perceiving the world without any visual cue in total absence of vision must often be based on verbal descriptions of events (for instance, following cricket on the radio). Congenitally blind people are therefore likely to depend more on memory in general, and on verbal memory in particular, to interact with the world. Visual cortex in blind subjects is also recruited for auditory processing and for nonvisual cognitive functions, providing further demonstrations that visual cortices can be reorganized to mediate nonvisual functions in the blind.

3793
Computer 114
A combined task based fMRI connectivity and VBM study to lateralization of memory function in pre-and post-surgery mesial temporal lobe epilepsy patients.
Kapil Chaudhary1, Senthil Kumaran2, Sarat P Chandra3, and Manjari Tripathi1

1Neurology, AIIMS, New Delhi, India, 2NMR, AIIMS, New Delhi, India, 3Neurosurgery, AIIMS, New Delhi, India

Patients with temporal lobe epilepsy (TLE) have associated cognitive dysfunction and memory impairment on anterior temporal lobe resection (ATLR). Semantic verbal memory reorganization was investigated using functional connectivity (FC) and VBM in pre-and post-operative TLE subjects and healthy controls. Reduction in GM concentration was observed in left temporal lobe post-operatively in comparison to pre-surgery session and healthy controls. Semantic verbal memory components revealed increased FC in right hemisphere with decreased memory scores at follow-up (6 months post-surgery) compared to that of pre-surgery, indicating damage in the medial temporal region due to surgical resection resulting in semantic verbal memory network dysfunction.

3794
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Working memory deficits in childhood cancer survivors: an fMRI study
Patricia Stefancin1, Christine Cahaney1, Robert Parker2, Thomas Preston1, Laura Hogan2, Rina Meyer2, Cara Giannillo1, Debra Giugliano1, and Tim Duong1

1Stony Brook Medicine, Stony Brook, NY, United States, 2Stony Brook Children's Hospital, Stony Brook, NY, United States

Little is known about the neural correlates of cognitive deficits in chemotherapy treated survivors of childhood cancer. We used event related fMRI to study working memory in childhood cancer survivors. Subjects underwent an n-back task to test working memory function. Patients showed reduced BOLD signal on correct responses compared to controls in the anterior cingulate, posterior cingulate, and sensory association cortices. Patients showed increased activation on error trials in the angular gyrus and superior parietal lobule. The affected brain regions are known to be involved in memory function, reward, motor planning and motivation. 

3795
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Detecting CBF to Explore Verbal Memory Impairment Mechanisms in Subcortical Stroke Patients
Caihong Wang1, Peifang Miao1, Sen Wei2, Kaiyu Wang3, and Jingliang Cheng1

1Department of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 3GE Healthcare MR Research, Beijing, China

In order to explore the neural substrates underlying verbal memory (VM) impairment in subcortical stroke patients, we recruited sixty patients with chronic subcortical stroke and sixty normal controls. 3D-ASL imaging was used to measure the resting-state values of voxel-wise cerebral blood flow (CBF) and the alterations of functional covariance network were detected. In this study, the different CBF levels in the stroke patients and the normal controls, as well as the close correlation between the CBF values and the VM scores, indicate that the VM impairment in stroke patients may be associated with the disconnection of frontal-lobe network. 

3796
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Influence of smoking cessation treatment by varenicline to brain—a resting-fMRI study
Peng Peng1, Chun-lin Li2, Bin Jing2, Shui-lian Chu3, Qing-lei Shi4, Xiu-qin Jia1, and Tao Jiang1

1Radiology, Beijing Chao-Yang Hospital, Beijing, China, 2School of biomedical engineering, Capital medical university, Beijing, China, 3Clinical research centre, Beijing Chao-Yang Hospital, Beijing, China, 4HC NEA DI MR Siemens Healthcare Ltd, Beijing, China

This study investigated the activation changes of brain regions in smokers before and after cessation treatment using a resting state fMRI. The results demonstrated that treated smokers will have improved functions of brain regions related to emotion and memory after using varenicline. This improvement is not only the direct benefit of quitting smoking, but also helps quitters cope with the discomfort and negative emotions of quitting. All subjects showed a decrease in smoking addiction and withdrawal response, suggesting that varenicline can help quitters maintain their withdrawal status.

3797
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Dynamic up- and down-regulation of large-scale cortical networks during task-on and task-off periods.
Katarzyna Anna Kazimierczak1,2, Karsten Specht1,3,4, Justyna Beresniewicz1,2, Kristiina Kompus1,2, René Westerhausen5, Renate Grüner4,6,7, Lars Ersland1,2,8, and Kenneth Hugdahl1,2,6,9

1Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway, 2NORMENT Centre of Excellence, University of Oslo, Oslo, Norway, 3Department of Education, The Arctic University of Norway, Tromsø, Norway, 4Mohn Medical Imaging and Visualization Centre, Haukeland University Hospital, Bergen, Norway, 5Institute of Psychology, Univeristy of Oslo, Oslo, Norway, 6Department of Radiology, Haukeland University Hospital, Bergen, Norway, 7Department of Physics and Technology, University of Bergen, Bergen, Norway, 8Department of Clinical Engineering, Haukeland University Hospital, Bergen, Norway, 9Division of Psychiatry, Haukeland University Hospital, Bergen, Norway

This study was intended to capture the dynamics of networks up- and down-regulation over time, with focus on the extrinsic mode network (EMN) and the default mode network (DMN), using functional magnetic resonance imaging (fMRI). Finite impulse response function (FIR) featured in the SPM software package was used to estimate the BOLD response. The results featured initial rapid activation of EMN in task-periods, while DMN began to drift towards up-regulation already by the end of the task-period. 

3798
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Abnormal local spontaneous brain activity revealed by resting-state fMRI as a biomarker for predicting radiation-induced neurocognitive dysfunction in patients with nasopharyngeal carcinoma
Yadi Yang1, Chuanmiao Xie1, Long Qian2, Zhipeng Li1, Yingwei Qiu3, and Xiaofei Lv1

1Department of Medical Imaging, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, China, 2GE Healthcare, MR Research China, Beijing, China, 3Department of Radiology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China

In this study, we hypothesize that radiation therapy induce longitudinal neurocognitive dysfunction in patients with nasopharyngeal carcinoma. To verify this hypothesis, resting-state functional magnetic resonance imaging (fMRI) was used to detect the local spontaneous brain activity in 38 patients with nasopharyngeal carcinoma 20 healthy controls at the baseline and follow-up examinations. The changes in brain activity at the early delayed stage after radiation therapy are then used to predict the brain functional impairment at a later stage. The results showed that radiation therapy may induce significant changes in reginal homogeneity in the brain, and such changes at early delayed stage may serve as a potential biomarker for predicting neurocognitive dysfunction at a later stage. 

3799
Computer 120
Abnormalities of intrinsic regional brain activity at resting state in schizophrenia: a meta-analysis of resting-state functional MRI
JiaYing Gong1,2, Junjing Wang3, Xiaomei Luo1, Guanmao Chen1, Huiyuan Huang4, Ruiwang Huang4, Li Huang1, and Ying Wang1

1Medical Imaging Center, First Affiliated Hospital of Jinan University, Guangzhou, China, 2Department of Radiology, Six Affiliated Hospital of Sun Yat-sen University, Guangzhou, China, 3Department of Applied Psychology, Guangdong University of Foreign Studies, Guangzhou, China, 4School of Psychology, Institute of Brain Research and Rehabilitation (IBRR), Center for the Study of Applied Psychology & MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou, China

Evidences of abnormal intrinsic brain activity in schizophrenia (SZ) are inconsistent demonstrated by previous studies. A meta-analysis that explored the differences of the ALFF between SZ patients (including first episode [FE] and chronic patients) and healthy controls were conducted. FE patients demonstrated decreased ALFF in the DMN and increased in the putamen, VN (visual network). Chronic patients showed decreased ALFF in the DMN, sensorimotor network, and VN and increased in the salience network, frontotemporal regions. Aberrant regional brain activity during the initial stage and widespread damage with the progression of disease contributes to understand the progressive pathophysiology feature of SZ.

3800
Computer 121
Graph theoretic analysis of language sub-networks in Arabic-English bilingual patients undergoing fMRI for pre-surgical planning
Shruti Agarwal1, Mona Mohamed1, Hanzhang Lu1,2, and Jay J Pillai1

1Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Kennedy Krieger Institute, Baltimore, MD, United States

Task fMRI is routinely performed on patients for pre-surgical planning to localize critical components of the language network and assess hemispheric language dominance. However, the cortical representation of language in bilingual patients (those who are fluent in more than one language) is more complex than in monolinguals, and may involve overlapping but distinct sub-networks. The focus of our current study is to assess the functional connectivity strength of language networks derived from task fMRI activation maps obtained using paradigms performed in both primary native (L1) and secondary (L2) languages in a group of Arabic-English bilingual patients.

3801
Computer 122
Altered connectivity following olfaction fMRI in Patients with Parkinson’s Disease: A comparative study using two different odors
Shefali Chaudhary1, S Senthil Kumaran1, Vinay Goyal2, Priyanka Bhat2, Ankita Sharma2, and Gauri Shanker Kaloiya3

1Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, India, 2Neurology, All India Institute of Medical Sciences, New Delhi, India, 3National Drug Dependence Treatment Centre, All India Institute of Medical Sciences, New Delhi, India

Olfactory impairments are one of the cardinal non-motor symptoms in Parkinson’s Disease (PD). Functional Connectivity analysis was carried out for olfaction task with floral fragrance (smell 1) and citrus fragrance (smell 2) on 10 PD patients (9M/1F, mean age ± SD=57.7±5.6 years). Main effects depicted heterogeneous connectivity and differential lateralization for both the smells. Amygdala and the thalamus were affected for both the smells in patients with PD and may be attributed to the pathology. Olfaction specificity for hippocampal connectivity in floral smell and for orbitofrontal, insula and anterior cingulate in citrus smell suggest differential recruitment of cognition linked areas.

3802
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Disrupted functional connectivity strength in overactive bladder syndrome patients
Long Zuo1, Shuangkun Wang1, Yang Zhou1, Hua Gu1, Biao Wang1, and Tao Jiang1

1Beijing Chaoyang Hospital, Beijing, China

A dysregulation of the brain-bladder control network has been revealed by the functional brain imaging studies. However, the brain functional connectivity strength (FCS) of OAB still remains unclear. Our study investigated the changes of intrinsic whole brain functional connectivity pattern in OAB using FCS. Patients with OAB have impaired pattern of FCS, which shows abnormal short-range and long-range FCS in brain regions associated with brain-bladder network. Behavioural treatments of the OAB based on fMRI may provide new sight into clinical practice.

3803
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Neuropsychological Assessments and ALFF across Multiple Categories of Carotid Artery Stenosis
MEI-YU YEH1,2, Changwei W. Wu2, Meng-Yang Ho3, Tsong-Hai Lee4, and Fu-Nien Wang1

1National Tsing Hua University, Hsinchu, Taiwan, 2Taipei Medical University, Taipei, Taiwan, 3Chang Gung University, Taoyuan, Taiwan, 4Chang Gung Memorial Hospital, Taoyuan, Taiwan

We explored the relationship between neuropsychological tests and ALFF based on three types of patients with carotid artery stenosis: unilateral stenosis, unilateral occlusion and bilateral stenosis. We found that patients with occlusion and bilateral stenosis had stronger ALFF than controls, but the neurophysiological results did not match the ALFF outcomes.

3804
Computer 125
Altered resting-state functional connectivity in patients with cervical vertigo
Cuili Kuang1, Yunfei Zha1, and Yang Fan2

1Renmin Hospital of Wuhan University, Wuhan, China, 2GE Healthcare China, Beijing, China

   As a pioneering work to cervical vertigo in functional connectivity perspective, in some extent, we discovered the potential specific spatiotemporal neuronal functional mechanisms alteration, and altered functional connections were correlated to clinical scale scores.  These findings might support complementary evidence for its clinical cognition.


MR-Guided HIFU & MR Thermometry

Exhibition Hall
Wednesday 13:30 - 14:30
 Interventional MRI

3805
Computer 126
Zero TE based screening for transcranial MR guided focused ultrasound
Jaime Caballero1, Rafael Rodríguez-Rojas1, Raul Martínez-Fernández1, Marta Del-Alamo1, Pablo Garcia-Polo2, and Jose A. Pineda-Pardo3

1hmCINAC, University Hospital HM Puerta del Sur, Móstoles, Spain, 2GE Healthcare, Madrid, Spain, 3Neuroimaging, hmCINAC, Móstoles, Spain

The high acoustic impedance of the skull limits the performance of tissue ablation applications with tcMRgFUS. Skull characterization is currently based on CT. Zero echo time (ZTE) images could represent a safer alternative in this matter. CT and ZTE images were acquired in sixteen essential tremor patients that underwent tcMRgFUS. Several skull measures were obtained for both images. ZTE and CT based metrics were strongly correlated. Furthermore skull thickness and the skull density ratio were able to predict the efficiency of the treatment. In conclusion, ZTE based measures are able to determine the suitability of a tcMRgFUS candidate.

3806
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Sacroiliac joint ablation in a chronic swine model using MRgFUS
Viola Rieke1, Ellen Liebenberg2, Eugene Ozhinsky3, Matthew Bucknor3, Carol Stillson3, Colin Yee3, Teri Moore3, and Roland Krug3

1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Orthopedic Surgery, University of California San Francisco, San Francisco, CA, United States, 3Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States

There is evidence that MRgFUS might be a very safe and effective minimally invasive technique to treat sacroiliac joint pain caused by arthritis and other degenerative changes. This study in a chronic swine model demonstrated safety and effectiveness of MRgFUS sacroiliac joint ablation and precise ablation of the posterior sacral nerve supply with MRgFUS. 

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Temporal changes in multiparametric imaging features of the prostate gland following MRgFUS ablation
Signy Holmes1, Ryan Brunsing1, Rachelle Bitton2, Bruce Daniel1, Geoffrey Sonn3, and Pejman Ghanouni1

1Department of Radiology, Stanford University School of Medicine, Stanford, CA, United States, 2Stanford University, Palo Alto, CA, United States, 3Department of Urology, Stanford University School of Medicine, Stanford, CA, United States

Magnetic resonance guided high intensity focused ultrasound (MRgFUS) can be used for focal therapy of prostate cancer. After treatment, these men remain in active surveillance. Effective monitoring of these men requires an understanding of the expected MRI appearance of the prostate after MRgFUS. Twenty-three patients treated with MRgFUS for focal, intermediate risk MR imaging-visible prostate cancer were followed with serial MRI for 6-24 months. We describe temporal changes in the qualitative and quantitative multiparametric imaging features of the prostate gland post-MRgFUS ablation to aid radiologists to better interpret follow-up examinations to detect residual or new disease.

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Longitudinal assessment of Focused ultrasound (FUS) induced Blood-Brain Barrier (BBB) opening in the non-human primate under 7T MRI
Kaiyue Wang1,2 and Chih-Hung Chai3

1Interdisciplinary Institute of Neuroscience and Technology (ZIINT), Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China, Hangzhou, China, 2College of Biomedical Engineering & Instrument Science,Zhejiang University, Hangzhou, China, Hangzhou, China, 3School of Medicine, Department of Electrical Engineering, Chang Gung University, Taoyuan, Taiwan, Taiwan, China

Microbubble-mediated focused ultrasound can noninvasively induce reversible blood-brain barrier (BBB) opening in both rodents and non-human primates. However, it remains unclear whether FUS-induced BBB opening is accompanied by neuromodulation. Here we longitudinally characterized the duration and the functional effects of FUS-induced BBB opening by measuring changes in contrast-enhanced T1-weighted images (T1-WIs) and blood-oxygen-level dependent (BOLD) responses, respectively. The results show that BBB recovered at 6.5h post-FUS exposure. The blood-oxygen-level dependent (BOLD) changes during the visual stimulus pre- and post- FUS exposure didn't show similar change trend in both hemispheres. The results of fMRI-guided FUS may contribute to the development of FUS-induced BBB opening for clinical applications.

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Rapid MR-guided-HIFU using Convolution-based Reconstruction and Parallel Imaging (CORE-PI)
Efrat Shimron1 and Haim Azhari1

1Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel

A novel reconstruction method for accelerated Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) thermometry is presented. This method utilizes multi-coil acquisition, k-space undersampling and the recently introduced Convolution-based Reconstruction for Parallel Imaging (CORE-PI) technique. The proposed method utilizes data sparsity in the Stationary Wavelet Transform (SWT) domain. It is a parameter-free, non-iterative and calibrationless method. Retrospective experiments with in-vivo data from clinical human prostate ablation treatments show that the proposed method produces accurate temperature maps from two-fold and three-fold subsampled k-space data. The method is therefore suitable for real time application.

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Enhancement of the HIFU thermal effect in ex-vivo kidneys using a new class of endovascular sono-sensitizers
Orane Lorton1, Pauline Guillemin1, Romain Breguet2, Stéphane Desgranges3, Laura Gui1, François Lazeyras4, Antonio Nastasi5, Lindsey A. Crowe2, Nicolas Taulier6, Christiane Contino-Pépin3, and Rares Salomir1,2

1Image Guided Interventions Laboratory, Faculty of Medicine, University of Geneva, Geneva, Switzerland, Geneva, Switzerland, 2Radiology Department, University Hospitals of Geneva, Geneva, Switzerland, Geneva, Switzerland, 3University of Avignon, CBSA-IBMM (UMR5247), Avignon, France, Avignon, Switzerland, 4Department of Radiology and Medical Informatics, University of Geneva, Switzerland, Geneva, Switzerland, 5Research and Development Laboratory, Visceral and Transplantation Service, University Hospital Geneva, Geneva, Switzerland., Geneva, Switzerland, 6Sorbonne Universités, UPMC Univ Paris 06, CNRS, INSERM, Laboratoire d’Imagerie Biomédicale (LIB), F-75006, Paris, France, Paris, Switzerland

Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) is a promising approach for the non-invasive ablation of localized tumors. Ablation of highly perfused tumors is challenging due to the heat sink effect. We developed a new concept of endovascular liquid core micro-droplets, used as sono-sensitizers for the enhanced absorption of the HIFU beam. We demonstrated the improvement of the HIFU thermal effect after adjunction of sono-activable micro-droplets in the perfusion fluid of freshly excised viable pig kidneys. Temperature maps were computed using the PRFS method to prove the enhancement of thermal contrast.

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Novel Acoustic Coupling Design to Improve MR Imaging Guidance for Focused Ultrasound Surgery
Steven P Allen1, Thomas Steeves2, Eli Vlaisavljevich3, Austin Fergusson4, Richey M Davis5, and Craig H Meyer1,6

1Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Department of Mechanical Engineering, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 3Department of Biomedical Engineering, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 4Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 5Department of Chemical Engineering, Virginia Polytechnic Institute and State School, Blacksburg, VA, United States, 6Department of Radiology, University of Virginia, Charlottesville, VA, United States

We explore the feasibility of an acoustic coupling medium that is invisible to both T2-weighted anatomical scans and MR thermometry scans during MR-guided focused ultrasound surgery and yet still preserves the cooling and acoustic coupling functions normally provided by water.

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Detecting T1-based Signal Reduction in Focused Ultrasound Heating of Bone using a 3D Spiral Ultra-Short Echo Time Sequence
Yekaterina K Gilbo1, Helen Sporkin1, Sam W Fielden2, John P Mugler3, Grady W Miller3, Steven P Allen1, and Craig H Meyer1

1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Autism and Developmental Medicine Institute, Geisinger Health System, Danville, PA, United States, 3Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States

MR-guided Focused Ultrasound (MRgFUS) is used transcranially to ablate brain tissue for the treatment of neurological diseases. Temperature monitoring of the skull is desired for increasing treatment safety and efficacy. Proton resonance frequency shift MR fails to detect heating in the cortical bone of the skull. T1-based MR thermometry uses T1 mapping to observe a linear increase in T1 with temperature but requires long acquisitions. We demonstrate a new thermometry method dependent on the linear relationship between signal magnitude from a T1-weighted 3D Spiral Ultra-short Echo Time sequence and test it across three scanners in multiple trials.

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Assessing the effect of pre-focal fat on the feasibility of delivering MR guided high intensity focused ultrasound (MRgHIFU) treatment of intra-pelvic tumors
Sharon L Giles1, Ian Rivens2, Gail R ter Haar2, and Nandita M deSouza1

1CRUK Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden Hospital, London, United Kingdom, 2Therapeutic Ultrasound, The Institute of Cancer Research, London, United Kingdom

Models were used to simulate the pre-focal tissue distributions encountered when treating intra-pelvic tumors with magnetic resonance guided high intensity focused ultrasound (MRgHIFU). Focal peak temperature and thermal dose volumes were considerably affected by depth and fat thickness. Exposures of 300 W for ≥20 s (≥6 kJ) were required to generate measurable 30EM dose contours 8 cm deep (6 cm pre-focal fat). The relative distributions of fat and muscle layers had minimal effect on focal heating, but influenced location of potentially damaging pre-focal heating. MRgHIFU treatments to deep-seated intra-pelvic tumors require methods for improving dose delivery at depth.

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Registration of In Vivo MR images to Volumetric Histopathology
Blake Zimmerman1, Sara Johnson1, Jill Shea2, Henrik Odeen3, Elaine Hillas2, Candace Winterton3, Robb Merrill3, Sarang Joshi1, and Allison Payne3

1Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, 2Department of Surgery, University of Utah, Salt Lake City, UT, United States, 3Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States

As MR guided focused ultrasound (MRgFUS) treatments evolve to treat oncological diseases, the ability to accurately assess the efficacy of treatment is critical. Although there are several MR metrics proposed for assessing MRgFUS treatments, they have not been rigorously validated against gold standard histopathology treatment assessment. Current validation studies that register MR to histopathology do not comprehensively account for all deformations during histological processing. We present a rigorous MR to histopathology registration pipeline that estimates deformation at every step that can be used to accurately validate the efficacy of oncological MRgFUS treatment. 

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Transcranial focused ultrasound localization in Money at 3T
Yangzi Qiao1, Chao Zou1, Jo Lee1, Xiaojing Long1, Teng Ma1, Changjun Tie1, Xin Liu1, and Hairong Zheng1

1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China

Focused ultrasound has been a fast developing technology for non-invasive neuromodulation. Monkey is a good animal model for studying the mechanism of focused ultrasound on neural network. However, the ultrasound beam would be greatly attenuated and distorted by the monkey skull, making the precise focal localization a crucial step. MR-ARFI with little thermal effect was an attracting tool for focus localization. In this study, we investigated the transcranial MR-ARFI in monkey at 3T system. With high performance of the customer designed monkey head coil and the strong gradient system, reliable and repeatable results were obtained. 

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Longitudinal Registration for Voxel-wise Correlation of MRgFUS Treatment Assessment Metrics
Sara L Johnson1, Blake Zimmerman1, Jill Shea2, Elaine Hillas2, Henrik Odéen3, Sarang Joshi1, and Allison Payne3

1Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, 2Department of Surgery, University of Utah, Salt Lake City, UT, United States, 3Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States

The acute assessment of MRgFUS therapies with metrics such as thermal dose and contrast-enhanced (CE) imaging have been shown to under- or over-estimate the final ablation lesion as assessed by delayed imaging or histological outcomes. The aim of this study is to longitudinally register MRgFUS treatment images to a final lesion outcome as determined by CE-T1w imaging three days post-treatment for voxel-wise analysis of these errors. MR thermometry (MRTI), cumulative thermal dose (CTD), and acute CE-T1w images are co-registered to Day 3 CE-T1w with millimeter accuracy and assessed for their predictive value. 

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Fast 3D MR thermometry using echo-shifted sequence with parallel acquisition acceleration
Rui Jiang1, Chao Zou1, Yangzi Qiao1, Changjun Tie1, Xin Liu1, and Hairong Zheng1

1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, CAS, Shenzhen, China

A high-precision, fast MR thermometry is always preferred for HIFU monitoring. However, the coverage of MRT is also important for the safety concern as the unwanted burn usually takes place in the tissue interface which might be far away from the focal area. In this work, we combined 3D echo-shifted GRE sequence with 2D parallel imaging acceleration to implement a fast 3D MRT.

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A Principal Component Analysis based Multi-baseline Phase Correction Method for PRF Thermometry
Waqas Majeed1, Rainer Schneider2, Sunil Patil1, Florian Maier2, Henrik Odéen3, Dennis L Parker3, John Roberts3, Adrienne E Campbell4, and Himanshu Bhat1

1Siemens Medical Solutions USA Inc., Malvern, PA, United States, 2Siemens Healthcare GmbH, Erlangen, Germany, 3Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 4Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States

The use of Proton Resonance Frequency (PRF) based thermometry with thermal therapy procedures is indispensable. Variation in background phase due to motion related changes in B0 is a major source of inaccuracy in PRF thermometry. In this work we propose a novel Principal Component Analysis (PCA) based multi-baseline phase correction approach. We compare this approach with two existing methods using in-vivo human brain and heart data, and demonstrate significant reduction in bias as well as variance of temperature difference estimates. The proposed approach may increase the accuracy of PRF thermometry in or near moving organs, and hence result in improved clinical outcome.

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Development of  2D Cartesian, radial and UTE MP2RAGE sequences for fast T1 mapping: application to MR thermometry
Thibaut L Faller1, Alice Rousseau1, Aurélien J Trotier1, Sylvain Miraux1, and Emeline J Ribot1

1CNRS - Univ. Bordeaux, CRMSB UMR 5536, Bordeaux Cedex, France

A surrogate strategy to the Proton Resonance Frequency technique that fails when short T2* tissue are present is the measurement of the longitudinal relaxation times T1. In order to monitor temperature in real-time, a 2D version of the Magnetization Prepared 2 Gradient Echo (MP2RAGE) sequence has been developed, and the cartesian encoding has been replaced by radial ones to obtain an ultra-short Echo Time (UTE). This enabled to measure T1 of short T2*-phantoms and to perform MR thermometry every 8s over a wide range of temperatures and consequently of T1.

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Active Tracking-based cardiac triggering of MR thermometry for MRI-guided cardiac ablation
Ronald Mooiweer1, Rainer Schneider2, Radhouene Neji1,3, Thomas Pohl2, Tom Lloyd4, Rahul K Mukherjee1, Mark O'Neill1, Reza Razavi1, and Sébastien Roujol1

1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2Siemens Healthcare GmbH, Erlangen, Germany, 3MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, 4Imricor Medical Systems, Burnsville, MN, United States

MR thermometry can be used for MRI-guided cardiac ablations, but ECG-triggering is not always effective. We propose to use the Active Tracking (AT) functionality included in the catheter to prospectively trigger the thermometry measurements. Modules measuring the position of the AT microcoil were interleaved with a thermometry sequence, which were repeated until a trigger condition is detected. Experiments showed successful triggering in a beating heart phantom, with a temperature stability of 1.12±0.36°C. For in-vivo interventional application, respiratory motion will need to be taken into account. 

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A flexible 11-channel coil array for MR-guided high-intensity focused ultrasound (HIFU) studies on rabbit leg muscle at 3 T
Qiaoyan Chen 1, Rui Jiang1, Changjun Tie1, Jianhong Wen1, Xing Yang2, Chao Zou1, Xiaoliang Zhang3,4, Xin Liu1, Hairong Zheng1, and Ye Li1

1Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2High Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China, Chengdu, China, 3Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 4UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, United States

    Signal-to-noise ratio (SNR) of the radio frequency (RF) receive coil array is a critical factor affecting the accuracy of temperature measurement in MR-guided high-intensity focused ultrasound (HIFU) for local heating. In this work, a flexible 11-channel coil array was designed, constructed and evaluated for MR-guided HIFU studies on rabbit leg muscle at a 3 T MRI scanner. Compared to a commercial available 4-channel flexible coil array, the dedicated 11-channel coil array provides improved performance in SNR, parallel imaging capability, and the accuracy of temperature measurement.

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Comparison of Cartesian MR thermometry approaches for focused ultrasound brain applications
Henrik Odéen1, Viola Rieke1, Sunil Patil2, John Roberts1, Himanshu Bhat3, Bradley D. Bolster Jr.4, and Dennis L Parker1

1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Siemens Healthineers, Baltimore, MD, United States, 3Siemens Healthineers, Boston, MA, United States, 4Siemens Healthineers, Salt Lake City, UT, United States

Magnetic resonance guided focused ultrasound using MR thermometry (MRT) for therapy guidance is a promising thermal therapy for a wide range of neurological disorders. The current MRT method acquires a single 2D slice with low readout bandwidth to increase SNR and MRT precision, compensating for the fact that the body coil is used to receive during treatments. In this work we investigate trade-offs between 2D and 3D GRE and EPI approaches of MRT for brain FUS applications. A comparison between using the body coil and two 4-channel flex coils is also performed.

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Improved MR thermometry using saturation bands to suppress water signal
Henrik Odéen1, Allison Payne1, Viola Rieke1, Sunil Patil2, Bradley D. Bolster Jr.3, Himanshu Bhat4, and Dennis L Parker1

1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2Siemens Healthineers, Baltimore, MD, United States, 3Siemens Healthineers, Salt Lake City, UT, United States, 4Siemens Healthineers, Boston, MA, United States

MR guided focused ultrasound (MRgFUS) treatments are routinely monitored by MR thermometry (MRT). Image quality and MRT precision can be significantly degraded by water motion in the water bath used to couple the FUS transducer to the target tissue. This problem is especially challenging when the water bath surrounds the target tissue. In this work we investigate the use of saturation bands to suppress the unwanted signal in dedicated breast and brain MRgFUS systems. It is shown that using saturation bands to suppress signal from the water bath significantly reduces artifacts and improves MRT precision with potentially shorter scan times.

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k-space MR Thermometry Using k-space Energy Spectrum Analysis
Shenyan Zong1, Bruno Madore2, Guofeng Shen3, and Chang-Sheng Mei4

1Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 2Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States, 3Med-X Research Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 4Department of Physics, Soochow University, Taipei, Taiwan

The goal of this work was to perform MR thermometry in the k-space domain, as opposed to the image domain, on the premise that a k-space approach might be better suited at capturing spatial trends. The method relies on the fact that spatial gradients in temperature cause k-space shifts in signals for heated materials. Traditional proton resonance frequency (PRF) thermometry was also performed, for validation purposes. 

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A Dual-Echo bSSFP Imaging Method for Proton Resonance Frequency-Based Thermometry and Analysis of Phase Behavior in bSSFP
Seohee So1, JaeJin Cho1, Kinam Kwon1, Byungjai Kim1, and HyunWook Park1

1School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea, Republic of

Proton resonance frequency thermometry is useful to estimate temperature change that is proportional to the resonance frequency change. In this study, we propose a dual-echo bSSFP thermometry method that generates a high intensity signal and linear phase to the frequency shift. Off-centered acquisition in the balanced steady-state free precession creates an imperfect linear phase with respect to the frequency shift. The dual-echo acquisition method compensates for the phase nonlinearity and generates phase information that is linearly proportional to the frequency shift. This phase linearization makes it possible to accurately measure the proton resonance frequency shift caused by temperature change.

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Design, evaluation and application of a 16-channel Frequency Synthesizer Module for Thermal Magnetic Resonance
Haopeng Han1, Shuailin Wang2, Thomas Wilhelm Eigentler1, Lukas Winter3, Eckhard Grass4,5, and Thoralf Niendorf1,6,7

1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 2Beijing Deepvision Technology Co., Ltd., Beijing, China, 3Physikalische Technische Bundesanstalt (PTB), Berlin, Germany, 4IHP – Leibniz-Institut für innovative Mikroelektronik, Frankfurt (Oder), Germany, 5Institute of Computer Science, Humboldt-Universität zu Berlin, Berlin, Germany, 6Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany, 7MRI.TOOLS GmbH, Berlin, Germany

Thermal Magnetic Resonance makes use of the physics of the radio frequency fields applied at ultrahigh field magnetic resonance imaging. While UHF-MRI enables measuring temperature in vivo, highly localized power deposition can be achieved by interfering RF waveforms with a shortened wavelength. This constitutes a means for supervised in vivo temperature modulation. The number of RF signals and the signals’ properties greatly affect the heating performance. In this work, a 16-channel frequency synthesizer module was developed as an RF signal source for Thermal MR. Preliminary experiments were conducted to demonstrate that the proposed module is suitable for Thermal MR.

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Ultra-Wideband Self-Grounded Bow-Tie Antenna Building Block for Thermal Intervention, Diagnostic MRI and MR Thermometry at 7.0 Tesla
Thomas Wilhelm Eigentler1, Lukas Winter2, Haopeng Han1, Eva Oberacker1, Andre Kuehne3, Laura Boehmert1, Hana Dobsicek Trefna4, and Thoralf Niendorf1,3,5

1Berlin Ultrahigh Field Facility, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 2Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany, 3MRI.TOOLS GmbH, Berlin, Germany, 4Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden, 5Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany

A compact resonator antenna for broadband thermal intervention, diagnostic proton (1H) and fluorine (19F) imaging and MR-Thermometry was developed for operating at 7.0T MRI. The antenna is based on the concept of a self-grounded bow-tie (SGBT) antenna to enable thermal intervention frequencies ranging from 250MHz to 516MHz. The self-grounded bow-tie resonator antenna is smaller and lighter compared to previous dipole-antenna designs, enabling a high-density multi-channel array. The proposed antenna is demonstrated to be suitable for diagnostic imaging, thermal intervention, and MR thermometry.

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Power Considerations for Radiofrequency Applicator Concepts for Thermal Magnetic Resonance Interventions in the Brain at 297 MHz
Eva Oberacker1, Andre Kuehne2, Celal Oezerdem1, Jason M Millward1, Cecilia Diesch1, Thomas Wilhelm Eigentler1, Jacek Nadobny3, Sebastian Zschaeck3, Pirus Ghadjar3, Peter Wust3, Lukas Winter4, and Thoralf Niendorf1,2,5

1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 2MRI.TOOLS GmbH, Berlin, Germany, 3Clinic for Radiation Oncology, Charite University Medicine, Berlin, Germany, 4Biomedizinische Magnetresonanz, Physikalisch Technische Bundesanstalt, Berlin, Germany, 5Experimental and Clinical Research Center (ECRC), joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany

There is a pressing need to implement Thermal MR therapies in the brain, particularly to sensitize treatment of aggressive cancers like glioblastoma multiforme. Given the high power transmission regime of Thermal MR therapies, it is crucial to understand the engineering constraints affecting RF power losses, since inaccurate estimates could compromise the efficiency and precision of the therapy. Here we conducted a thorough simulation of five RF applicator designs, using realistic loss estimates of material and electrical components, and considering antenna design, position and coupling. Results from simulated and patient-derived data underscore that clinical requirements must balance with practical engineering constraints.

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Flip angle optimization and in vitro demonstration of 2D DESPOT1-based fat thermometry
Beatrice Lena1, Clemens Bos1, Chrit T.W. Moonen1, Max A. Viergever1, and Lambertus W. Bartels1

1University Medical Center Utrecht, Utrecht, Netherlands

During MR-HIFU ablations, fat MR thermometry (MRT) is needed for monitoring temperature in adipose tissues (both in target regions and in subcutaneous fat in the near field of the ultrasound beam). It can be based on T1 mapping calculated with 2D-DESPOT1 method and corrected for the FA variation over the slice profile. However, difficulties arise in the choice of 2 flip angles optimized for the whole expected range of T1s in fat MRT. We identify the optimal settings through simulation and demonstrate the feasibility of fat MR thermometry through 2D DESPOT1 sequences in phantom experiments.


Non-Thermal Interventional MRI

Exhibition Hall
Wednesday 13:30 - 14:30
 Interventional MRI

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Performance of an aerosol jet-deposited wireless resonant marker: in vitro temperature measurements and in vivo visualization
Caroline D. Jordan1, Bradford R. H. Thorne1, Arjun Wadhwa2, Eugene Ozhinsky1, Vincent Fratello2, Sravani Kondapavulur1,3,4, Aaron D. Losey1, Teri Moore1, Carol Stillson1, Colin Yee1, Ronald D. Watkins5, Greig C. Scott6, Alastair J. Martin1, Xiaoliang Zhang1, Mark W. Wilson1, and Steven W. Hetts1

1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Quest Integrated, Kent, WA, United States, 3Graduate Program in Bioengineering, UC Berkeley-UCSF, Berkeley, CA, United States, 4Bioengineering and Therapeutic Sciences, University of California, Berkeley, Berkeley, CA, United States, 5Radiology, Stanford University, Stanford, CA, United States, 6Electrical Engineering, Stanford University, Stanford, CA, United States

Endovascular catheter-based procedures under MRI can be challenging as standard fabrication methods for markers are rigid and bulky, and new microfabrication methods need more analysis on their tracking characteristics. We analyzed a wireless resonant circuit tracking marker that was printed using aerosol jet deposition on a polymer catheter. In a phantom, we acquired bSSFP sequences and a B1+ map, and measured temperature using probes and MR thermometry. In vivo, in the carotid arteries, we acquired GRE sequences and a B1+ map. The marker demonstrated good signal, with minimal temperature increases, suggesting that these markers have good tracking characteristics.

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Motion-Adaptive Temporal Resolution for Radial Real-Time Imaging at a Low-Field MR-Linac
Florian Friedrich1,2, Philipp Mann3,4, C. Katharina Spindeldreier5, Peter Bachert1,2, Mark E. Ladd1, Sebastian Klüter5, and Benjamin R. Knowles1

1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany, 5Department of Radiation Oncology, University Hospital of Heidelberg, Heidelberg, Germany

Hybrid MRI linear accelerators (MR-linacs) enable real-time image guidance during radiotherapy. Under real-time MRI, a compromise must be found between spatio-temporal resolution and SNR, whereas to precisely track tumour position, both should be maximised. The presented method implements a motion-adaptive image reconstruction based on a golden-angle radial acquisition scheme. This allows producing SNR-optimised images under periods of small motion and images optimised for temporal resolution when motion is larger. The technique was implemented at a low-field MR-linac (0.35T) to image a free-breathing volunteer and a motion phantom.

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Interleaved White Marker Contrast with bSSFP Real-Time Imaging for Deep Learning based Needle Localization in MR-Guided Percutaneous Interventions
Jonathan Weine1,2, Rainer Schneider1, Urte Kägebein3, Bennet Hensen3, Frank Wacker3, and Florian Maier1

1Siemens Healthcare, Erlangen, Germany, 2TU Dortmund, Dortmund, Germany, 3Hannover Medical School, Hannover, Germany

Automatic localization of needles in real-time images can facilitate MR-guided percutaneous interventions. It enables automatic slice repositioning and targeting support and, thus, allows for faster workflows. The improvement of deep learning based passive needle tracking by using both, anatomical and positive contrast images as input was investigated. A prototype bSSFP sequence for interleaved acquisition of k-space lines for conventional and positive contrast with Cartesian readout was implemented and  evaluated ex-vivo and in-vivo. The U-Net segmentation algorithm showed superior performance when using both contrasts. In conclusion, this method is a promising approach for robust needle localization in real-time interventional workflows.

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A simple freehand technique for MRI-guided needle localization of suspicious breast lesions
Qing Zhang1, Zhiguo Zhuang1, Dandan Zhang1, Jianrong Xu1, and Jia Hua1

1radiology, Renji Hospital, Medical College of Shanghai Jiao Tong University, shanghai, China

A total of 273 patients who received needle localization with a bare-hand technique for suspicious breast lesions by using 1.5 T MR-guided were included in our study.  The puncture method was similar to CT-guided needle localization of lung nodule. The success rate of localization was 100% (273/273). Procedure time of all the cases ranged from 5 to 30 min (mean, 14.3 min). Our MRI-guided bare-hand needle localization of suspicious breast lesions is a handy, safe, rapid, and accurate interventional method. The lesions that are located at axillary region of breast,areola area, and the special area near the chest wall can all be precisely localized. 

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Highly Undersampled Radial Passive Marker Tracking with Phase-only Cross-Correlation (POCC) for Real Time Image Guidance
Andreas Reichert1, Simon Reiss1, Michael Bock1, Michael Vogele2, and Axel Joachim Krafft1

1Department of Radiology, Medical Physics, Medical Center ‐ University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Interventional Systems GmbH, Kitzbuehel, Austria

Marker tracking with phase-only cross correlation (POCC) is an efficient technique to localize instruments during percutaneous MR-guided interventions in closed-bore MR systems. Unfortunately, POCC is time-consuming, as additional marker images need to be continuously acquired. Here, we present a drastically accelerated POCC sequence that uses radially undersampled images to detect the passive marker. With a modified POCC algorithm this sequence can detect marker movements within less than 108ms thus providing a very fast position feedback. The precision of the POCC sequence was evaluated in phantom measurements, and a possible in vivo targeting scenario was demonstrated in a volunteer.

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Radial Simultaneous Multi Slice Imaging for Marker Tracking
Andreas Reichert1, Axel Joachim Krafft1, and Michael Bock1

1Department of Radiology, Medical Physics, Medical Center ‐ University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany

The phase-only cross correlation (POCC) algorithm efficiently and accurately detects passive MR markers used as needle guides. In a POCC sequence the marker is automatically detected in two cross-sectional images to continuously visualize the planned needle trajectory during motion. Image acquisition of the marker, however, is very time consuming which degrades the temporal resolution. Here, it is shown that two simultaneously acquired, highly undersampled radial images - together with the consideration of the point-spread-function in the POCC algorithm - can track the marker at substantially shorter acquisition times.

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MRI Driven Augmented Reality Image-Guidance Platform for Myocardial Cell Delivery
Mitchell Doughty1, Jill Weyers2, Xiuling Qi2, Graham Wright2, Michael Laflamme3, and Nilesh Ghugre2

1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Schulich Heart Research Program, Sunnybrook Research Institute, Toronto, ON, Canada, 3McEwen Centre for Regenerative Medicine, University Health Network, Toronto, ON, Canada

Myocardial infarction is a leading cause of heart failure, a condition with a 5-year mortality rate of ~50%. Current HF management techniques aim to slow disease progression rather than improve function. Cardiac regenerative medicine through cell-based approaches offers the potential to repopulate non-contractile scar tissue. However, regions of scar are not well delineated during the cell-delivery procedures, and accurate cell placement is vital to realize positive outcomes from therapy. We aim to develop a novel integrative image-guidance solution combining MRI for myocardial scar characterization with augmented reality via a head-mounted display to visualize critical MRI information intraoperatively and guide delivery.

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Phantom Study of Novel Biopsy Needle and Assisted Robotic System Designed for Prostate Biopsy Procedure under MRI
Davut Ibrahim Mahcicek1, Dursun Korel Yildirim1, Gokce Kasaci1, and Ozgur Kocaturk1

1Biomedical Engineering, Bogazici University, Istanbul, Turkey

In this study, a novel MRI guided prostate biopsy device was designed, produced and tested under MRI. In this scope, a MRI compatible, remote controlled, transrectal biopsy delivery system, a MRI compatible biopsy gun, a MRI compatible, biopsy needle which can be tracked under MRI, and a computer based control unit were designed and a prototype was produced. The robotic prostate biopsy device prototype was tested under MRI with in-vitro experiments using a commercially available prostate phantom.

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Ten Minutes for the Brain to Settle: an In-vivo Investigation of Positional Brain Shift
Stefano Zappala1, Nicholas Bennion2, Slawomir Kusmia3, Jing Wu1, Sam Evans2, Derek Jones3, and David Marshall1

1Computer Science and Informatics, Cardiff University, Cardiff, United Kingdom, 2School of Engineering, Cardiff University, Cardiff, United Kingdom, 3Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, United Kingdom

Positional brain shift (BS), as the physiological sagging of the brain under the effect of gravity, has a magnitude that is comparable to the accuracy of neuronavigational systems. It is a complex interaction of gravity, anatomical boundaries and tissue mesostructure. A comprehensive investigation of such deformation is needed. This study aims to provide a rich set of volumetric measures to infer the pattern of deformation as well as the time evolution of positional BS. Results show that positional BS is a relatively fast process, stabilised in 10 minutes, with local variations strongly dependent on the variability of anatomical structures between different subjects.

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Motion tracking using simultaneous MR and 4D ultrasound acquisition for image guided radiation therapy
Thomas KF Foo1, Bo Wang1, Jhimli Mitra1, David Mills1, L Scott Smith1, Heather Chan1, Aqsa Patel1, Shourya Sarcar1, Eric Fiveland1, Warren Lee1, Sydney Jupitz2, Alan McMillan3, James H Holmes3, Wes Culberson2, Michael Bassetti4, Andrew Shepard2, and Bryan Bednarz2

1GE Global Research, Niskayuna, NY, United States, 2Medical Physics, University of Wisconsin, Madison, WI, United States, 3Radiology, University of Wisconsin, Madison, WI, United States, 4Human Oncology, University of Wisconsin, Madison, WI, United States

An MR-compatible 4D ultrasound probe allows hands-free, simultaneous MR and ultrasound image acquisition. This new imaging capability provides a path for tracking tumor target motion during radiation therapy, as an alternative to an integrated MR-LINAC system. To facilitate this, the ability to track the motion of fiducial markers as an indication of respiratory state is essential. In our approach, as the MR images are acquired outside of the radiation therapy procedure, motion tracking of endogenous ultrasound fiducials is proposed to determine respiratory states.

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Catheter-based Arterial Input Function for Quantitative Perfusion Measurements with Intra-arterial Injection
Simon Stephan1, Simon Reiss1, Thomas Lottner1, Ali Caglar Özen1, and Michael Bock1

1Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany

MR-guided vascular interventions allow for direct injection of contrast agent (CA) through a catheter, which can be used for perfusion measurements of the target tissue, for example, the myocardium in MR-guided coronary catheterizations. For a quantitative perfusion measurement an arterial input function (AIF) is required that describes the CA concentration-time curve in the artery. In this work we show initial results of two methods to determine the AIF during an intervention and demonstrate the feasibility of measuring the AIF in intra-arterial CA injections based on the signal of an active guiding catheter.

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Modeling of Active Shimming of Metallic Needles for Interventional MRI
Saikat Sengupta1

1Department of Radiology, Vanderbilt University Medical Center, Nashville, TN, United States

Needle artifacts caused by large magnetic susceptibility differences between metallic needles and stylets and the surrounding tissue are a persistent problem in interventional MRI. In this abstract, we present the concept, design and modeling results of a active shim system for needles inspired from degaussing coils used in naval vessels. Field disturbance induced by a Titanium needle at 3 Tesla is modeled and an active orthogonal shim coil insert design is presented to demonstrate shimming of the field variation around the needle. This work lays the foundation for designing full generalized active shim systems for Interventional MRI probes. 

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A Machine Learning Based Biomechanical Model for Real-time MR-guided Neuro-intervention
Suhao Qiu1, Alexa Singer1,2, Changxin Lai1, Blanca Zufiria1,2, Danni Wang1, Yao Li1, Bomin Sun3, Yiping Du1, Zhi-Pei Liang4, and Yuan Feng1

1Biomedeical Engineering, Shanghai Jiaotong University, Shanghai, China, 2KTH Royal Institute of Technology, Stockholm, Sweden, 3Functional Neurosurgery, Shanghai Jiaotong University, Shanghai, China, 4Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States

Magnetic resonance (MR) guided neuro interventions could be combined with robotic assisted manipulation to achieve optimal performance. Patient specific model constructed from MR images of the brain could have the best biophysical fidelity but suffers from high computational cost. For real-time applications, we proposed to construct an Artificial Neural Network (ANN) based on the training from computational outputs of Finite element Analysis (FEA). Results demonstrate the ability to achieve accurate predictions given by a mean square error (MSE) of 0.0338 mm2 within 10ms. 

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MRI artifact simulation for clinically relevant MRI sequences for guidance of prostate HDR brachytherapy
Ellis Beld1, Marinus A. Moerland1, Max A. Viergever2, Jan J.W. Lagendijk1, and Peter R. Seevinck2

1Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands, 2Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

Object localization by MRI artifact simulation and template matching is valuable for MRI-guided HDR brachytherapy. Simulations of the artifacts induced by an HDR brachytherapy source and titanium needle were implemented for four types of MRI sequences: spoiled gradient echo, spin echo, bSSFP and bSSFP-SPAIR. The simulated artifacts were compared to MR images acquired in a phantom study and applied for object localization. High correspondences between the simulations and MR images were found as well as only slight variations between the obtained object positions for all applied sequences. This enables object localization for clinically relevant MRI sequences which allow anatomy visualization.

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Real-time Automatic Tip Tracking of Gadolinium-filled Balloon Wedge Catheter during MR-guided Cardiac Catheterization
Rohini Vidya Shankar1, Radhouene Neji1,2, Phuoc Duong1, Bram Ruijsink1, Kuberan Pushparajah1, Reza Razavi1, and Sébastien Roujol1

1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom

MRI-guided cardiac catheterisation procedures are commonly performed using balloon wedge catheters which are currently manually tracked. Furthermore, these procedures require frequent manual adjustment of the slice positioning during catheter navigation. In this study, we sought to develop a novel acquisition and reconstruction framework that enables automatic tracking of a gadolinium-filled balloon wedge catheter using (a) real-time partial saturation with increased spatial coverage, (b) automatic image-based estimation of the catheter balloon position, and (c) real-time slice tracking. The proposed framework is demonstrated during an MRI-guided cardiac catheterisation experiment in a 3D printed heart phantom.

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Ferromagnetic markers for interventional MRI devices at 0.55T
Burcu Basar1, Merdim Sonmez1, Ram Paul2, Ozgur Kocaturk1, Daniel A. Herzka1, Robert J. Lederman1, and Adrienne E. Campbell-Washburn1

1NIH, Bethesda, MD, United States, 2Cook Medical, Bloomington, IN, United States

Interventional cardiac MRI has been hampered for decades by the lack of safe and visible devices. Guidewires (long, elongated metals) risk RF-induced heating under MR, and often incorporate ferromagnetic markers (e.g.stainless steel) that can be used for image guidance. We propose MR-guided interventions at 0.55T to avoid RF-induced heating. Here we show that at 0.55T, ferromagnetic markers maintain visibility and create identical artifacts to those observed at 1.5T. We show that using a high-performance low field MRI system may enable progress in interventional MRI due to improved device safety with retained image quality. 

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Clinical MRI-guided right heart catheterization with standard metallic devices using a high performance 0.55T system
Adrienne E Campbell-Washburn1, Toby Rogers1, Jaffar M Khan1, Burcu Basar1, Rajiv Ramasawmy1, Laurie P Grant1, William H Schenke1, Delaney R McGuirt1, Annette P Stine1, Daniel A Herzka1, and Robert J Lederman1

1Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States

MRI-guidance of invasive cardiovascular procedures has been limited by the unavailability of safe devices. Most cardiovascular procedures require long conductive devices (eg. guidewires and catheters) that are susceptible to RF-induced heating. Because heating is related quadratically to field strength, we propose to reduce the MRI field strength to 0.55T. Using a custom high-performance 0.55T MRI system, we performed MRI-guided catheterizations on patients with commercial metallic guidewires using standard high flip angle bSSSP real-time imaging to produce good image quality and contrast without RF-induced heating. Low field MRI combined with high-performance hardware will be fundamentally enabling for MRI guidance of invasive procedures.

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Proof-of-concept of retrospective gating for interventional cardiac MRI using catheter microcoils readings.
Marylène DELCEY1,2,3,4, Pierre BOUR1,3,4, Valery OZENNE1,3,4, Wadie BENHASSEN2, and Bruno QUESSON1,3,4

1IHU LIRYC, PESSAC, France, 2Siemens Healthcare, Saint-Denis, France, 3Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France, 4INSERM U1045, Bordeaux, France

In the context of radiofrequency ablation of cardiac arrhythmia, a catheter is inserted into the heart for contact electrophysiology recording and/or ablating the arrhythmogenic substrate. In this context, we propose to exploit MR-compatible microcoils located near the catheter tip to estimate the local motion of the heart. For this, a tracking module was interleaved with segments of a radial acquisition in a FLASH sequence. k-space segments were sorted retrospectively according to tracking readings before image reconstruction. Using this approach, artifact free images of a pig in vivo could be reconstructed.

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3D CNN-based synthetic CT generation for head and neck radiotherapy using a clinically used turbo spin-echo T2-weighted sequence
Mateusz C. Florkow1, Anna M. Dinkla2, Frank Zijlstra1, Matteo Maspero2, Mark H.F. Savenije2, Patricia A.H. Doornaert2, Marijn van Stralen1,3, Marielle E.P. Philippens2, Cornelis A.T. van den Berg2, and Peter R. Seevinck1,3

1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 2Radiotherapy Department, University Medical Center Utrecht, Utrecht, Netherlands, 3MRIguidance, Utrecht, Netherlands

Deep learning-based synthetic CT (sCT) generation models are often based on T1-weighted gradient echo sequences. However, these sequences are generally not used for tumor/organs-at-risk delineation. In this study, we trained a U-Net type neural network using T2-weighted turbo spin-echo images from the clinical radiotherapy treatment planning protocol originally used for tumor/organs-at-risk contouring. The use of clinical images preserves scan times and facilitates soft tissue delineation on the source images of the sCTs, avoiding registrations. We showed that sCTs generated by the trained model provide accurate dosimetric results while limiting CT-induced streaking dental artefacts.

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MINIMA – Minimally invasive, image guided ablation using MRI
Chris Payne1, Rebecca Baker1, Matin J Mohseni1, John J Connell1, Peter Stephen Patrick1, Yichao Yu1, Bernard Siow1, Mark F Lythgoe1, and Quentin A Pankhurst2

1Centre for Advanced Biomedical Imaging, UCL, London, United Kingdom, 2Davy-Faraday Research laboratories, UCL, London, United Kingdom

Minimally invasive, focal therapies aim to deliver more effective treatment to the patient while reducing off target effects. As such, we have developed MINIMA, a minimally invasive, image-guided ablation MRI technique, whereby a magnetic thermoseed can be manoeuvred through tissue, localised with real time imaging and then heated to cause cell death. We demonstrate submillimetre precision of movement through ex vivo brain tissue and that the seed can be heated via application of radiowaves to cause well defined regions of cell death. These results show that MINIMA is a promising new technique that could help transform MRI into a brand new theranostic device.

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Imaging latency of Golden Angle 2D MRI using real-time GPU-accelerated image reconstruction for MR-guided radiotherapy
Pim Borman1, Bas Raaymakers1, and Markus Glitzner1

1Radiotherapy, UMC Utrecht, Utrecht, Netherlands

For tumor tracking in MRI-guided radiotherapy it is important to minimize the latency between the moment of anatomic change and its appearance on the MR image. By using a 2D golden angle sampling trajectory in combination with a sliding window reconstruction, the latency can be decoupled from the frame rate, yielding frame rates of up to one repetition time. We implemented a real-time GPU-accelerated reconstruction pipeline where k-space data is directly streamed to a reconstruction server during acquisition. Using this we investigated the influence of the sliding window width on the latency, reconstruction time, frame rate and image quality.

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Feasibility and Demonstration of Controlled, Comprehensive Delivery of Clot-busting Drugs for MR Image-Guided Intracerebral Clot Evacuation
Robert Moskwa1, Miles Olsen1, Jen Meudt2, Robby Weyker2, Morgan McCue2, Terry Oakes3, Ethan Brodsky1, Dhanansayan Shanmuganayagam2, Azam Ahmed4, and Walter Block1

1Medical Physics, University of Wisconsin, Madison, WI, United States, 2Animal Sciences, University of Wisconsin, Madison, WI, United States, 3Radiology, University of Wisconsin, Madison, WI, United States, 4Neurosurgery, University of Wisconsin, Madison, WI, United States

A recent NIH Trial has shown success in minimizing the effects of intracerebral hemorrhage through insertion of a minimally invasive catheter into the clot through a craniotomy. The catheter then injects 1 ml of clot-busting drugs followed by an 8 hour period of draining the lysed blood.  The conservative procedure is repeated for 3-5 days as only very small dosages can be administered due to CT’s inability to directly monitor the drug’s safe distribution.  We demonstrate how pressurized infusions can create broader treatments that lyse the clot rapidly while MRI visualizes the drug distributions to maintain safety. 

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EVALUATION OF FPI BASED CUSTOM FORCE SENSOR DESIGN FOR BIOPSY NEEDLES
Dogangun Uzun1, Okan Ulgen1, and Ozgur Kocaturk1

1Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey

In this work, an MRI compatible Fabry-Pérot Interferometry (FPI) based force sensor is designed and fabricated using novel methods, and integrated into an 18-gauge nitinol biopsy needle. The resolution of the FPI based sensor is increased by coating optical fibers with magnesium and titanium thin film. The force sensing needle is tested by in vitro experiments using a prostate phantom and in vivo animal experiments under MRI.

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A Body-Mounted Robot with Integrated Single Loop Coil for MR-Guided Arthrography
Reza Monfaredi1, Wolfgang Loew2, Christopher Ireland2, Viktoriya Beskin1, Ronald Pratt2, Randy Giaquinto2, Charles (Chuck) Dumoulin2, Kevin Cleary1, and Karun Sharma1

1Children's Hospital / SZI, Washington DC, DC, United States, 2Imaging Research Center, Cincinnati Children's Hospital, Cincinnati, OH, United States

The purpose of this project is to streamline the workflow for robotic-assisted MR-guided arthrography by integrating a single loop coil in the base / mounting adapter of the robot. This coil provides sufficient spatial coverage and sensitivity to localize anatomic points of interest and registration fiducials embedded in the robot. Integration of the coil with the robot places the imaging coil as close as possible to the patient and reduces the number of devices that need to be managed during an interventional procedure.  Quantitative results for SNR and an end-to-end targeting study using a phantom are reported in the abstract.

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Automatic pelvic bone registration of low-field MRI to pre-operative 3T-MRA for vascular interventions
Derk J. Slotman1,2, Jordy K. van Zandwijk1,2, Frank F.J. Simonis1, Ferdi van der Heijden3, Robert H. Geelkerken2, and Bennie ten Haken1

1Magnetic Detection & Imaging, University of Twente, Enschede, Netherlands, 2Vascular surgery, Medisch Spectrum Twente, Enschede, Netherlands, 3Robotics and Mechatronics, University of Twente, Enschede, Netherlands

Intra-operative low-field magnetic resonance imaging (LF-MRI) is characterized by poor spatial resolution limiting its use in endovascular catheter tracking with fluoroscopy. Fusion of LF-MRI with 3T-MRI may overcome this issue. To fuse both volumes, we automatically segmented a pelvis from an LF-MRI scan, based on cortical bone detection with Laplacian edge detection.  A similarity of 66% was reached between automatic and manual segmentation. Subsequently, the segmented volume was automatically registered to a 3T-MRA. Compared to a Procrustes based manual registration, the automatic registration resulted in a root-mean-square error of 3 mm. 


fMRI: Connectivity Methods

Exhibition Hall
Wednesday 14:30 - 15:30
 fMRI

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Brain connectivity assessed by mechanical covariance
Haitao Ge1,2, Armando Manduca3, David T. Jones4, Clifford R. Jack JR1, John Huston III1, Richard L. Ehman1, and Matthew C. Murphy1

1Radiology, Mayo Clinic, Rochester, MN, United States, 2School of Medical Imaging, Xuzhou Medical University, Xuzhou, China, 3Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States, 4Neurology, Mayo Clinic, Rochester, MN, United States

  • The human connectome is a comprehensive representation of the brain’s network architecture. Novel imaging tools may provide new insights into this organization in both health and disease. Given the established sensitivity of the brain’s mechanical properties to its function, we test whether MR elastography-based stiffness estimates can be used to measure brain connectivity. We show that the mechanical connectivity network (MCN) is significantly correlated with established structural and functional connectivity methods, and also exhibits the expected small world organization. Nonetheless, MCN topological measures significantly differ from the existing methods, suggesting MRE may provide a new perspective on the brain’s organization.The human connectome is a comprehensive representation of the brain’s network architecture. Novel imaging tools may provide new insights into this organization in both health and disease. Given the established sensitivity of the brain’s mechanical properties to its function, we test whether MR elastography-based stiffness estimates can be used to measure brain connectivity. We show that the mechanical connectivity network (MCN) is significantly correlated with established structural and functional connectivity methods, and also exhibits the expected small world organization. Nonetheless, MCN topological measures significantly differ from the existing methods, suggesting MRE may provide a new perspective on the brain’s organization.
MRI-based measures play an important role in the field of connectomics, which aims to map the brain’s network organization in health and disease. Novel imaging tools may provide new insights into this organization. In this work, we tested whether MR elastography-based stiffness estimates can be used to measure brain connectivity. The mechanical connectivity network (MCN) was significantly correlated with established structural and functional connectivity methods, and also exhibited the expected small world organization. Nonetheless, MCN topological measures significantly differed from the existing methods, suggesting MRE may provide a new perspective on the brain’s organization.


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Functional Connectome Fingerprinting using Recurrent Neural Networks Does Not Depend on the Temporal Structure of the Data
Gokce Sarar1, Shili Wang2, Jiawei Ren3, and Thomas T. Liu1

1UCSD Center for Functional MRI, La Jolla, CA, United States, 2Beihang University, Beijing, China, 3Canyon Crest Academy, San Diego, CA, United States

Functional connectome fingerprinting can identify individuals with high accuracy with long duration scans (> 6 min) but the performance significantly degrades with shorter (72s) duration scans.   It has been argued that Recurrent Neural Networks (RNN) can achieve high identification performance with short duration data by taking advantage of temporal information in the fMRI signals. We test this claim by permuting the temporal ordering of the data. We show that the RNN can achieve high accuracy for short duration data even when the temporal structure is destroyed, suggesting that the RNN performance depends primarily on the spatial correlation of the data. 

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Arterial spin labeling pre-processing strategies for functional connectivity analysis
Kalen J Petersen1, Daniel O Claassen1, and Manus J Donahue1,2

1Neurology, Vanderbilt University Medical Center, Nashville, TN, United States, 2Radiology, Vanderbilt University Medical Center, Nashville, TN, United States

Arterial spin labeling-based functional connectivity (ASL-FC) is an emerging method to identify synchronous brain networks from perfusion fluctuations. ASL-FC may compensate for some susceptibility-induced limitations in blood-oxygenation-level-dependent (BOLD)-FC, however ASL-FC processing strategies are only beginning to be investigated. We evaluate optimized ASL-FC pre-processing for network detection, testing the effects of six pre-processing strategies by comparing spatial and temporal features with BOLD-FC in major brain networks. Spatial smoothing, surround subtraction, and global signal regression are necessary to increase ASL-FC sensitivity. ASL-FC also allows for low frequencies to be interrogated, which contain high power but are inaccessible to common BOLD-FC analyses.

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Automatic Identification of ICA Components using A Generative Adversarial Network
Yiyu Chou1, Snehashis Roy1, Catie Chang2, John Butman3, and Dzung L Pham1

1Center for Neuroscience and Regenerative Medicine, Bethesda, MD, United States, 2Laboratory of Functional and Molecular Imaging, NINDS, Bethesda, MD, United States, 3Radiology and Imaging Sciences, NIH, Bethesda, MD, United States

Manual classification of the components derived from ICA analysis of rsfMRI data as particular functional brain resting state networks (RSNs) can be labor intensive and requires expertise; hence, a fully automatic algorithm that can reliably classify these RSNs is desirable. In this paper, we introduce a generative adversarial network (GAN) based method for performing this task. The proposed method achieves over 93% classification accuracy and out-performs the traditional convolutional neural network (CNN) and template matching methods.

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Simultaneous measurement of functional connectivity and cerebrovascular reactivity (CVR): feasibility of vasculature-normalized fcMRI
Xirui Hou1, Peiying Liu2, Hong Gu3, Micaela Chan4, Li Yang2, Shin-Lei Peng5, Yihong Yang3, Denise Park4, and Hanzhang Lu1,2

1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2The Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Neuroimaging Research Branch, National Institute on Drug Abuse, Baltimore, MD, United States, 4Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, United States, 5Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan

Although widely used in fMRI to assess functional connectivity (FC), the blood-oxygenation-level-dependent (BOLD) signal is not merely a representation of neural activity, but also inherently modulated by vascular physiology. It is therefore desirable to conduct FC mapping with consideration of vascular properties, ideally in the same scan. The present work demonstr