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Digital Poster - Monday
Weekend and Oral

Digital Poster (no CME credit)

Tuesday Digital Poster Wednesday Digital Poster Thursday Digital Poster

Monday Digital Poster (No CME Credit)

Musculoskeletal

08:15
1259 - 1433

Engineering

09:15
1434 - 1608

Body: Breast, Chest, Abdomen, Pelvis

13:45
1609 - 1777
14:45
1778 - 1950

Cardiovascular

16:00
1951 - 2124
17:00
2125 - 2224

Spectroscopy & Non-Proton MR

17:00
2225 - 2298

Muscle 1

Exhibition Hall
Monday 8:15 - 9:15
 Musculoskeletal

1259
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Characterizing respiratory muscle composition and function in Duchenne muscular dystrophy using dynamic MRI and chemical shift-encoded imaging
Alison Marie Barnard1, Donovan Lott1, Abhinandan Batra1, William Triplett1, Sean Forbes1, Samuel Riehl1, Rebecca Willcocks1, Barbara Smith1, Krista Vandenborne1, and Glenn Walter2

1Department of Physical Therapy, University of Florida, Gainesville, FL, United States, 2Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, United States

In Duchenne muscular dystrophy (DMD), respiratory muscle weakness leads to eventual respiratory failure.  For this investigation, dynamic MRI was utilized to characterize diaphragm and chest wall dynamics during breathing, and chemical shift-encoded imaging was utilized to assess fatty infiltration in accessory respiratory muscles in 36 individuals with DMD and 12 unaffected controls.  For maximal inspirations, individuals with DMD had significantly reduced anterior-posterior chest expansion, and a subgroup with poor respiratory function had decreased diaphragm descent (normalized to height).  The expiratory muscles had high levels of fatty infiltration, and muscle fat fraction was correlated with measures of expiratory muscle strength.  

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Can be Pi2 signal in 31P MR spectra a biomarker of critical limb ischemia in diabetic patients?
Petr Sedivy1, Monika Dezortova1, Miloslav Drobny1, Michal Dubsky2, and Milan Hajek1

1MR-Unit, Dept. Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic, 2Dept. Diabetology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic

A group of 65 diabetic patients with critical limb ischemia was studied by rest and dynamic phosphorous MR spectroscopy. An unknown signal in the position 5.2 – 5.4 ppm (labeled as Pi2) was observed in calf muscle spectra of 14 patients. Two hypotheses of the Pi2 signal explanation were taken into the consideration: a) phosphorus in alkaline phosphate pool or b) phosphorus in an unknown phosphomonoester. Results support hypothesis a) and we think that Pi2 signal at 5.4 ppm in patients with diabetic foot disease could be considered as the biomarker of the most severe muscular damage.

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Regional thigh muscle composition based on chemical shift encoding-based water-fat MRI and its association with muscle strength
Maximilian Thomas Löffler1, Sarah Schlaeger1,2, Stephanie Inhuber3, Michael Dieckmeyer1, Dominik Weidlich2, Ansgar Schwirtz3, Ernst J. Rummeny2, Claus Zimmer1, Jan S. Kirschke1, Dimitrios Karampinos2, and Thomas Baum1

1Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany, 2Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany, 3Department of Sport and Health Sciences, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany

Chemical shift encoding-based water-fat MRI derived proton density fat fraction (PDFF) of the thigh muscles bears potential as a surrogate marker in subjects with osteoarthritis, sarcopenia, and neuromuscular disorders. Muscle PDFF has shown to correlate with isometric strength at the thigh and spine. However, MR-based muscle fat quantification requires time-consuming segmentation of multiple muscle compartments. Therefore, we investigated if segmentation of single compartment muscles and of different levels of the thigh influences the relation of PDFF to isometric strength. The present study demonstrated that PDFF measurements can be limited to an entire muscle compartment, independent of sampling level.

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Evaluation of Muscle Degeneration in Amyotrophic Lateral Sclerosis Patients Using MR Cytography
Sudarshan Ragunathan1, Laura C Bell1, Ashley M Stokes1, Nicole Turcotte2, Shafeeq Ladha3, and C Chad Quarles1

1Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, 2Research-ALS, Barrow Neurological Institute, Phoenix, AZ, United States, 3Neurology, Barrow Neurological Institute, Phoenix, AZ, United States

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that affects motor neurons resulting in progressive muscle atrophy. The heterogeneous nature of disease progression has limited the reliability and robustness of current clinical indicators used in disease monitoring. To address the need for reproducible, quantitative biomarkers, we propose the applicability of Magnetic Resonance Cytography (MRC) to characterize ALS induced changes to muscle myofiber microstructure. In this clinical study, the role of MRC as a potential biomarker was demonstrated by identifying changes to muscle cytoarchitecture in the lower extremities among ALS patients when compared with healthy muscle.  

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Creatine CEST at 3T following in magnet exercise shows differences in heart failure patients with preserved ejection fraction compared to healthy and hypertensive controls
Neil Wilson1, Payman Zamani2, Elizabeth Proto2, Kevin D'Aquilla1, Dushyant Kumar1, Deepa Thakuri1, Hari Hariharan1, Shana McCormack3, Julio Chirinos2, and Ravinder Reddy1

1CMROI, University of Pennsylvania, Philadelphia, PA, United States, 2Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, United States, 3Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, PA, United States

Exercise intolerance is a hallmark of heart failure. Here, we have shown for the first time that parameters derived from ROI-based analysis of creatine-weighted CEST signals following exercise can be used to distinguish HFpEF patients from HTN and healthy controls. Identifying these group differences is uniquely possible because CrCEST can measure muscle specific metabolism with high spatial resolution and sensitivity.

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Aerobic exercise enhances 31P MRS measured mitochondrial function independent of statin use
Jill M Slade1, George S Abela2, David M Hurley1, and Ronald A Meyer3

1Radiology, Michigan State University, East Lansing, MI, United States, 2Medicine, Michigan State University, East Lansing, MI, United States, 3Physiology, Michigan State University, East Lansing, MI, United States

Phosphorus MRS is the gold standard measure of  in vivo mitochondrial function. In this study, 31P MRS was used to examine exercise-induced adaptations in mitochondrial function in the presence of concurrent statin use. The results show that aerobic exercise training significantly improved muscle oxidative capacity of the plantar flexor muscles in older adults independent of statin use. 

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The novel visualization technique of fast and slow muscle fibers using q-space imaging: Clinical study
Daisuke Nakashima1, Junichi Hata2,3,4, Yasushi Sera5, Takeo Nagura6, Morio Matsumoto1, Hideyuki Okano4, and Masaya Nakamura1

1Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan, 2RIKEN Brain Science Institute, Saitama, Japan, 3Central Institute for Experimental Animals, Kanagawa, Japan, 4Department of Physiology, Keio University School of Medicine, Tokyo, Japan, 5Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan, 6Department of Clinical Biomechanics, Keio University School of Medicine, Tokyo, Japan

Skeletal muscles include fast and slow muscle fibers. However, a non-invasive approach for appropriately investigating the characteristics of muscles is not available. The present study aimed to determine whether q-space imaging can distinguish between fast fiber dominant tibialis anterior muscle (TA) and slow fiber dominant soleus muscle (SOL). T2WI, FA and ADC maps could not represent the difference between TA and SOL. On the other hand, Kurtosis map could visualize the characteristics of TA and SOL. q-space imaging is a promising method to non-invasively estimate the fiber type ratio in skeletal muscles.

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Whole-Body Mapping of Spontaneous Mechanical Activities in Musculature
Martin Schwartz1,2, Petros Martirosian1, Thomas Küstner1,2,3, Günter Steidle1, Thorsten Feiweier4, Bin Yang2, and Fritz Schick1

1Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Tübingen, Germany, 2Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, 3School of Biomedical Engineering & Imaging Sciences, King’s College London, St. Thomas’ Hospital, London, United Kingdom, 4Siemens Healthcare GmbH, Erlangen, Germany

Whole-body quantification of spontaneous mechanical activities is of high interest for the assessment of the activity distribution in healthy and non-healthy population. Therefore, a measurement protocol and spatial mapping is investigated for accurate quantification of small subtle spontaneous activities in the human skeletal musculature over the whole-body. This work enables to assess spontaneous activity in muscular regions which are important for potential evaluation and grading in neuromuscular disorders.

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Deep Learning-Based Automatic Estimation of Volume and Fat Fraction in Abductor Muscles and their Associations with T1ρ and T2 in Hip Osteoarthritis Patients
Radhika Tibrewala1, Valentina Pedoia1, Carla Kinnunen1, Tijana Popovic1, Richard Souza1,2, and Sharmila Majumdar1

1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 2Physical Therapy and Rehabilitation Science, University of California San Francisco, San Francisco, CA, United States

In Osteoarthritis, cartilage degeneration can be accompanied by muscle weakness. T and T2 relaxation times have been used to probe cartilage degeneration. This study aims to develop an automatic machine-learning based segmentation and quantification pipeline to estimate the volumes and fat fractions of the three hip abductor muscles and study their associations with T and T2 relaxation times. Our results showed fast, reliable segmentations the hip abductor muscles and voxel based correlations between T and fat fraction and T2 and volumes of the muscles.

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Evaluation of inter- and intramuscular differences using multi-slice T2* measurements after an in-magnet stepping exercise.
Thom T. J. Veeger1, Celine Baligand1, Andrew Webb1, Jurriaan H. de Groot2, and Hermien E. Kan1

1Radiology, Leiden University Medical Center, Leiden, Netherlands, 2Rehabilitation, Leiden University Medical Center, Leiden, Netherlands

In this study we explored the feasibility of using an MR-compatible ergometer mimicking stair climbing to study differences in T2* after exercise between and within different thigh muscles. Four healthy subjects performed a 10-minute stepping exercise inside a 3T. Participants exercised at either a high rate of perceived exertion (RPE) or a low RPE. Clear differences between low and high RPE and different muscles, but not within muscles, were found. This shows that it is possible to use stair-climbing using an MR-compatible ergometer to study differences between and within muscles in response to exercise. 

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A neural network approach for estimating muscle perfusion from DCE-MRI data
Christopher C Conlin1, Xiaowan Li1, Stephen Decker2, Christopher J Hanrahan1, Gwenael Layec2, Nan Hu3, Vivian S Lee4, and Jeff L Zhang1

1Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, MA, United States, 3Division of Biostatistics, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States, 4Verily Life Sciences, Cambridge, MA, United States

Perfusion is an important aspect of calf muscle function that can be measured with dynamic contrast-enhanced (DCE) MRI. However, conventional methods for quantifying perfusion from DCE-MRI data require an appropriate tracer-kinetic model, which may not be available clinically. In this study, we examined the feasibility of neural networks (NNs) for quantifying calf-muscle perfusion from DCE-MRI data. We found that NNs estimate perfusion with accuracy comparable to conventional methods, without the need for a tracer-kinetic model. NNs like those developed in this study can be readily incorporated into ordinary MRI scanner software, facilitating routine quantitative perfusion analysis with DCE-MRI.

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Correlation between skeletal muscle fat content and insulin resistance in patients with type 2 diabetes mellitus
Fuyao Yu1, Huadong Zhou1, Fengzhe Wang1, Jiazheng Wang2, and Shinong Pan1

1Medical Imaging, Shengjing Hospital affiliated to China Medical University, Shenyang, Liaoning, China, 2Medical Imaging, Philips Healthcare, Beijing, China

To quantitatively investigate various parts of the thigh skeletal muscle fat content in patients with type 2 diabetes to explore its correlation with insulin resistance via MRI.

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Visualization of Aquaporin 4 using Time-dependent Diffusion MRI in Mouse Skeletal Muscle
Junichi Hata1,2,3, Takayuki Obata4, Yasuhiko Tachibana4, Yawara Haga1, Mai Mizumura1, Daisuke Nakashima2, Yasushi Sera2, Masaya Nakamura2, and Hideyuki Okano1,2

1Center for Brain Science, RIKEN, Wako, Japan, 2Keio University, Tokyo, Japan, 3Central Institute for Experimental Animals, Kanagawa, Japan, 4National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan

We focused on aquaporin 4 in skeletal muscle and attempted to visualize its function using time-dependent diffusion magnetic resonance imaging (MRI). In addition, the validity of the muscle cell type characteristics was evaluated by immunostaining. The diffusion time was adjusted with the PG-STE method using a 9.4-T MRI scanner. Diffusivity associated with a difference in the diffusion time was found to differ depending on the skeletal muscle type. Thus, it was possible to visualize the water molecule exchange rate of skeletal muscle cell membranes.

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Simulation based study of the effect of sub-voxel spatial distribution of permeability of muscle fibres as a function of diffusion time and b-value using a finite element model
Nadia A S Smith1, Jessica E Talbott1, Chris A Clark2, and Matt G Hall1,2

1National Physical Laboratory, Teddington, United Kingdom, 2UCL GOS Institute of Child Health, London, United Kingdom

We investigate the effect of the sub-voxel patterning of permeability in muscle tissue on the diffusion signal via a finite element simulation of diffusion MRI on a model of muscle tissue. We observe that permeability with a disordered pattern leads to statistically significant differences in diffusion signal at high b and longer diffusion times.

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The relation between fat calibration in multi-echo spin-echo water T2 mapping and STEAM fat T2 relaxation measurements
Martijn Froeling1, Eric Hughes2, Lara Schlaffke3, Hermien E Kan4, and Kieren G Hollingsworth2

1Department of Radiology, University medical center utrecht, Utrecht, Netherlands, 2Institute of Cellular Medicine, Newcastle University, Newcastle, United Kingdom, 3Department of Neurology BG, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany, 4Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands

The aim of this study was to quantitatively describe the relation between fat calibration in ME-SE water T2 mapping and STEAM fat T2 relaxation measurements in spectroscopy using j‑coupling simulations and investigate its effect on EPG water T2 mapping. Both ME-SE and STEAM T2 mapping methods to estimate the apparent fat T2 relaxation times are heavily influenced by J-coupling. As such the measured T2 relaxation time of fat using STEAM,  appears shorter and using ME-SE appears longer, ranging between values of 30 and 140 ms.

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Compressed-Sensing 4D Flow MRI of the Skeletal Muscle during Nerve vs Muscle Electrical Stimulation
Francesco Santini1,2, Nicolas Place3, Anna Hirschmann4, Ning Jin5, Oliver Bieri1,2, and Xeni Deligianni1,2

1Department of Radiology, Division of Radiological Physics, University Hospital Basel, Basel, Switzerland, 2Department of Biomedical Engineering, University of Basel, Basel, Switzerland, 3Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland, 4Department of Radiology, University Hospital Basel, Basel, Switzerland, 5Siemens Medical Solutions, Cleveland, OH, United States

The purpose of this study was to use dynamic 4D phase contrast MR imaging to compare the stimulation patterns of neuromuscular electrical stimulation of the calf muscles when delivered through the muscle belly or through the nerve trunk. Experiments were performed on healthy volunteers and strain maps were obtained for each stimulation modality. A more homogeneous activation of the muscle group was obtained for nerve stimulation, with overall lower strain values with respect to muscle stimulation.

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Extended phase graph model based tissue-water T2 estimation from CPMG image data in fat-infiltrated skeletal muscle: application in amyotrophic lateral sclerosis and Kennedy’s disease
Nick Zafeiropoulos1, Uros Klickovic1, Luca Zampedri1, Stephen J Wastling1, Christopher J Sinclair1, Jasper M Morrow1, Robert X Janiczek2, Enrico De Vita3, Tarek A Yousry1, Michael G Hanna1, Linda Greensmith1, Pietro Fratta1, and John S Thornton1

1UCL Queen Square Institute of Neurology, University College London, London, United Kingdom, 2Glaxo Smith Kline, London, United Kingdom, 3Department of Biomedical Engineering, King’s College London, London, United Kingdom

An MRI CPMG extended phase graph signal model was used to determine muscle-water T2 (T2m) in fat-infiltrated skeletal muscle, using a fixed two-component approximation to the fat signal. Stable estimates of T2m and apparent fat fraction (ffa) in the thigh muscles of amyotrophic lateral sclerosis and Kennedy’s disease patients and healthy controls were obtained. T2m were elevated in both patient groups, as was ffa with a distribution consistent with that obtained by 3-point Dixon MRI.

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Fascicle Ellipticity as an Explanation of Transverse Anisotropy in Diffusion MRI Measurements of Skeletal Muscle
Noel M. Naughton1, Anthony Z. Wang1, 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

Diffusion MRI of skeletal muscle exhibits a transverse anisotropy, the source of which has yet to be conclusively determined. To explore this, histological images were segmented into intracellular and extracellular domains and used to inform a direct numerical simulation of the Bloch-Torrey equation. Histology images were examined at the myocyte and fascicle scale and it was found that results from the fascicle images exhibited increased transverse anisotropy. These results suggest that fascicle organization may pay a hereunto unrecognized role in affecting dMRI in skeletal muscle. 

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Bidirectional Filtering for Psoas Major Muscle Magnetic Resonance Elastography
Surendra Maharjan1, Tomokazu Numano1, Tetsushi Habe1, Daiki Ito1, Takamichi Ueki1, Keisuke Igarashi1, and Toshiki Maeno1

1Radiological Sciences, Tokyo Metropolitan University, Tokyo, Japan

The purpose of this present work was to apply bidirectional spatio-temporal image filtering in the preferential direction of shear wave propagation in psoas major muscle Magnetic Resonance Elastography. The results suggested there was improvement in the wave propagation by using combined gaussian bandpass (GBP) and bidirectional filter in compared to GBP only. The calculation of local frequency estimate (LFE) stiffness value of PM muscle was not changed by applying the bidirectional filter.

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Gender- and age-related changes in trunk muscle composition using chemical shift encoding-based water-fat MRI
Egon Burian1, Daniela Franz2, Jan Syväri2, Christina Holzapfel3, Theresa Drabsch3, Jan S. Kirschke1, Ernst J. Rummeny2, Claus Zimmer1, Hans Hauner3, Dimitrios C. Karampinos2, and Thomas Baum1

1Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Munich, Germany, 2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Munich, Germany, 3Institute of Nutritional Medicine, Klinikum rechts der Isar, Munich, Germany

Chemical shift encoding-based water-fat MRI derived proton density fat fraction (PDFF) of muscles has been emerging as a surrogate marker for quantification of ectopic fat accumulation. Increased fatty deposits are a risk factor for metabolic and cardiovascular diseases. With skeletal muscle being the largest body compartment in adults, we are still at the beginning of understanding the functional consequences of these changes. The purpose of the present analysis was to investigate the gender- and age-related changes in PDFF of trunk musculature of healthy adults using chemical shift encoding-based water-fat MRI.

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Semi-quantitative MR muscle analysis of VCP inclusion body myopathy
Saya Horiuchi1,2, Hon J. Yu1, Toshimi Tando1, Taiki Nozaki2, Vincent J. Caiozzo3, Virginia E. Kimonis4, and Hiroshi Yoshioka1

1Department of Radiological Sciences, University of California, Irvine, Irvine, CA, United States, 2Radiology Department, St. Luke's International Hospital, Tokyo, Japan, 3Department of Orthopedics and Physiology & Biophysics, University of California, Irvine, Irvine, CA, United States, 4Division of Genetic and Genomic Medicine, Department of Pediatrics, University of California, Irvine, Irvine, CA, United States

This study was to demonstrate usefulness of semi-quantitative MR muscle analysis of VCP associated inclusion body myopathy associated with Paget and dementia (IBMPFD). Five-point scoring method was compared with quantification based on fat fraction analysis, and specific patterns of thigh muscle alterations were explored. The semi-quantification provided equivalent accuracy as quantification. The sartorius and adductor magnus were most affected by fatty infiltration, while the adductor longus and rectus femoris were well-preserved. Muscle volume decrease was more frequently seen in the hamstring and adductor muscles. This semi-quantitative method can be widely available in clinical settings and assist noninvasive initial/follow-up IBMPFD diagnosis.

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Quantitative evaluation of muscular microvascular permeability by DCE-MRI and texture analysis in diabetic rabbits
Bai Yu Liu1, Yun Fei Zha1, and Yang Fan2

1Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, China, 2GE Healthcare China, Beijing, China

Our purpose is to quantificationally evaluate the microvascular permeability and subtle changes in diabetic skeletal muscle by DCE-MRI and texture analysis. Alloxan-induced diabetic rabbits and normal rabbits were studied at fixed time points (0, 4, 8, 12, and 16 weeks). Permeability parameters Ktrans and Kep increased and then showed a downward trend, Ve increased and Vp decreased in diabetic group. Texture parameters based on Ktrans map showed difference between the two groups. We can draw a conclusion that the microvascular permeability of diabetic skeletal muscle increases while the perfusion decreases and texture analysis based on Ktrans map can detect these subtle changes in early stage.

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Multi-parametric MRI analysis of the temporal changes of induced damage and regeneration in dystrophic hind limb muscles
Ravneet Vohra1, Joshua Park1, Feng Zhang1, Guy Odom2, Jeffrey S. Chamberlain2,3,4, and Donghoon Lee1

1Department of Radiology, University of Washington, Seattle, WA, United States, 2Department of Neurology, University of Washington, Seattle, WA, United States, 3Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Washington, Seattle, WA, United States, 4Department of Biochemistery, University of Washington, Seattle, WA, United States

The mdx mouse model is one of the most commonly used animal models for Duchenne muscular dystrophy (DMD). Although the mdx model has a milder phenotype compared to patients with DMD, the model has shown the similarity in some histopathologic events resulting in wide utilizations in preclinical studies for both disease progression and therapeutic intervention. Over the years MRI has been increasingly being utilized to monitor the disease progression in dystrophic mice and DMD patients. We performed MRI to discriminate the time course of damage in regeneration in skeletal muscles if mdx mice.

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Mapping of myoglobin oxygen saturation dynamics in the calf during ischemia with a modified slab-selective 2D NMRSI pulse sequence at 3T.
Alfredo Liubomor Lopez Kolkovsky1,2, Martin Meyerspeer3,4, and Pierre G Carlier1,5

1NMR Laboratory, Institute of Myology, Paris, France, 2NMR Laboratory, CEA / DRF / IBFJ/ MIRCen, Paris, France, 3Division MR Physics, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, 4High Field MR Center, Medical University of Vienna, Vienna, Austria, 5NMR Laboratory, CEA / DRF / IBFJ / MIRCen, Paris, France

Myoglobin in its deoxygenated form is a 1H NMR visible biomarker of intracellular oxygenation. Its low concentration and very short relaxation times have been major challenges to map deoxy-myoglobin dynamically during a transient state, such as ischemia. Here, we interleaved the acquisition of a full 2D CSI data set at the dMb frequency (~79 ppm), a non-localized dMb spectrum and an anatomical image with radial encoding to track dMb dynamics during an ischemic bout with a temporal resolution of 3.5 seconds. Promising proof-of-concept results are shown. This method suggests a strong potential for energy metabolism studies in vivo.

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Simulated effect of diffusion time and skeletal muscle fiber size on the diffusion tensor
David Barnes Berry1, Erin Englund1, Vitaly Galinsky1, Chamindra Konersman1, Shaochen Chen1, Samuel Ward1, and Lawrence Frank1

1University of California, San Diego, La Jolla, CA, United States

The sensitivity of diffusion tensor imaging (DTI) to muscle fiber size is dependent upon diffusion time. However, there is no consensus on how to interpret data acquired at different diffusion times. In this study we simulated the relationship between muscle fiber size, diffusion time, and the resulting diffusion tensor in models with simplified and histology informed muscle fiber geometry, using a stimulated echo DTI pulse sequence. Maximum contrast between physiologically relevant fiber sizes was found at 130ms for diffusivity, and 170ms for fractional anisotropy measurements. This data may better inform pulse sequence parameter selection when performing DTI experiments in vivo.


Bone 1

Exhibition Hall
Monday 8:15 - 9:15
 Musculoskeletal

1284
Computer 26
Mapping collagen and water proton densities in tibial cortical bone using 3D ultrashort echo time cones (3D-UTE-Cones) MR imaging techniques
Saeed Jerban1, Yajun Ma1, Tan Guo1, Lidi Wan1, Hyungseok Jang1, Liang Li1, Eric Y Chang1,2, and Jiang Du1

1Radiology, University of california, San Diego, San Diego, CA, United States, 2Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

Spatial variations of cortical bone microstructure and mechanics can be described by mapping proton densities as exist in macromolecular, bound, and pore water pools. Comparing bone signal in ultrashort echo time MRI (UTE-MRI) and in inversion recovery UTE MRI against a known external reference signal enabled us to measure total, bound, and pore water proton densities. Measured total water proton density combined with macromolecular fraction from magnetization transfer modelling resulted in macromolecular proton density estimation. We observed strong correlation between proton densities and bone porosity. The developed technique was performed robustly on ten young subjects. This technique may aid diagnosing bone diseases and injuries.

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Ultrashort echo time MRI (UTE-MRI) quantifications of cortical bone varied between scans at room temperature and body temperature
Saeed Jerban1, Nikolaus Szeverenyi1, Yajun Ma1, Tan Guo1, Sarah To2, Eric Y Chang1,2, and Jiang Du1

1Radiology, University of california, San Diego, San Diego, CA, United States, 2Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

Several quantitative ultrashort echo time MRI (UTE-MRI) techniques have recently been employed to assess cortical bone microstructure. Such techniques were examined mostly ex vivo at room temperature and demonstrated strong correlations with bone microstructure as measured with micro computed tomography (μCT). However, MRI properties of cortical bone may differ in vivo due to higher temperature. We have investigated several UTE-MRI quantifications of cortical bone at body and room temperatures. Significant variations of bone UTE-MRI measures were observed between room and body temperatures. Implementing a linear correction method on UTE-MRI measures based on the presented results here might improve the validity of the techniques for in vivo studies.

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1H nuclei compartmentalization, exchange and self-diffusion in cortical bone by one- and two-dimensions NMR in homogeneous and inhomogeneous fields
Leonardo Brizi1, Marco Barbieri1, Claudia Testa1, and Paola Fantazzini1

1Physics and Astronomy, University of Bologna, Bologna, Italy

There is increasing interest in the study of water content, compartmentalization, exchange and its interaction with collagen in cortical bone for the evaluation of bone fracture risk. Here, we present the NMR characterization of 1H nuclei signals of the cortical bone. Different components (collagen, lipid, water) and different water compartments are identified measuring NMR properties and self-diffusion coefficients. The exchange between collagen and water protons is observed and an average residence time in the collagen is estimated. The results can contribute to optimize MRI protocols specifically for bone imaging and to characterize the role of water in this tissue.

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Perfect In-Phase Zero TE for Musculoskeletal Imaging
Mathias Engström1, Cristina Cozzini2, Michael Carl3, Graeme C McKinnon4, and Florian Wiesinger2

1GE Healthcare, Stockholm, Sweden, 2GE Healthcare, Munich, Germany, 3GE Healthcare, San Diego, CA, United States, 4GE Healthcare, Waukusha, WI, United States

Large FOV Zero Echo-Time (ZTE) has been challenging due to chemical shift artifacts, caused primarily by fat water dephasing, for low readout band-widths (rBW).  To correct for this Perfect In-Phase ZTE (pipZTE) is proposed where the chemical shift artifact is removed by acquiring data from multiple rBWs, and then separating the signal into an in-phase and off-resonance compartment in the reconstruction. In this work we explore the performance and properties of the pipZTE approach when scanning large FOV and demanding subjects.

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Comparison of Quantitative MRI Fat-Fraction measurement in SIJ joint on different scanner platforms
Alan Bainbridge1, Timothy J Bray2, Naomi Sakai2, Sarah Tansley3, Nicola Fulstow3, Raj Sengupta3, and Margaret A Hall-Craggs2

1Medical Physics and Biomedical Engineering, University College London Hospitals, London, United Kingdom, 2Centre for Medical Imaging, University College London, London, United Kingdom, 3Royal National Hospital for Rheumatic Diseases, Bath, United Kingdom

Proton density fat fraction (PDFF) measurements can quantify oedema and fat metaplasia in patients with spondyloarthritis.  The reproducibility of PDFF measurement in the bone marrow of the sacroiliac joint was assessed in volunteers on 3 systems from different manufacturers, using a range of specialist and base-level product protocols.   PDFF measurements on different platforms correlate well, but there is also a bias between the base-level and advanced methods.  Performing an offline reconstruction with a multi-peak fat model and a T2* correction term reduces this bias. 

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Age Estimation with the Greulich-Pyle Atlas using 3T MR Images of Hand and Wrist
Thomas Widek1,2, Pia Genet3,4, Thomas Ehammer1, Eva Scheurer5, and Thorsten Schwark1,6

1Ludwig Boltzmann Institute for Clinical Forensic Imaging, Graz, Austria, 2Medical University of Graz, Graz, Austria, 3University Centre of Legal Medicine, Lausanne University Hospital, Lausanne, Switzerland, 4University Centre of Legal Medicine, Geneva University Hospital, Geneva, Switzerland, 5Institute of Forensic Medicine, University of Basel - Health Department Basel-Stadt, Basel, Switzerland, 6Department of Forensic Medicine, Laboratoire national de santé, Dudelange, Luxembourg

Bone age estimation of the hand is very common both in a forensic context and for clinical purposes. Currently, this is done by assessing plain X-rays of the hand. This is a controversial issue, especially in the forensic context, as legal proceedings lack a medical indication for the use of ionizing radiation. The aim of the current study was to validate the use of the X-ray based Greulich-Pyle atlas method on hand MR images in a healthy male cohort. The results show that the application of the Greulich-Pyle method is feasible and that it can be used in daily routine.

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Fatty Acid Composition Assessed By 3T MRI in Systemic Lupus Erythematosus
Dimitri MARTEL1, Benjamin LEPORQ2, Ravinder R. REGATTE1, Stephen HONIG3, and Gregory CHANG1

1Radiology, NYU LANGONE HEALTH, New York City, NY, United States, 2Université de Lyon; CREATIS CNRS UMR 5220, Inserm U1206, INSA-Lyon, UCBL Lyon 1, Villeurbanne, France, 3Osteoporosis Center, Hospital for Joint Diseases, NYU LANGONE HEALTH, New York City, NY, United States

Systemic Lupus Erythematosus (SLE) is a chronic, inflammatory disease. Recent studies demonstrated an increased incidence of osteoporosis (OP) and fractures in SLE patients. Glucocorticoids (Gcs) are part of therapy for SLE and have with long-term intake deleterious effects on bone quality leading ultimately to Glucocorticoido-induced-osteoporosis. Our aim was to assess the marrow composition of a SLE population and compare it to that of OP patients, GCs user and young healthy women using 3T Chemical Shift Encoded- MRI (CSE-MRI). 

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Diffusion-Weighted MRI in Juvenile Osteochondritis Dissecans (JOCD) at 3T
Kai D. Ludwig1, Casey P. Johnson1,2, Stefan Zbyn1,2, Takashi Takahasi2, Shelly Marette2, Bradley J. Nelson3, Marc A. Thompkins3, Cathy S. Carlson4, and Jutta M. Ellermann1,2

1Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, United States, 2Radiology, University of Minnesota, Minneapolis, MN, United States, 3Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States, 4Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, United States

Diffusion-weighted MRI (DWI) may help elucidate the etiology and progression of juvenile osteochondritis dissecans (JOCD) by probing tissue/cellular characteristics of JOCD lesions and the underlying parent bone. In this study, we observed elevated DWI signal and increased apparent diffusion coefficient (ADC) values within and proximal to OCD lesions compared to surrounding bone marrow and control sites. ADC values within the lesion and the parent bone may help distinguish healing from non-healing lesions, thereby improving prognostication of JOCD and clinical decision making.

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An investigation of the relationship between type II collagen degradation products and MRI features of damage in knee osteoarthritis patients
Franklyn A Howe1, Vivian Ejindu2, Christine Heron2, Olakunbi Harrison3, Soraya Koushesh3, Lena Assi3, Anasuya Kuttapitiya4, Thomas R Barrick1, and Nidhi Sofat3

1Molecular & Clinical Sciences Research Institute, St George's, University of London, London, United Kingdom, 2St George's University Hospitals NHS Foundation Trust, London, United Kingdom, 3Institute of Infection & Immunity, St George's, University of London, London, United Kingdom, 4Great Ormond Street Hospital, London, United Kingdom

Knee osteoarthritis (OA) is a degenerative disease which produces pain and exhibits damage to cartilage, bone marrow and the development of synovitis. Biomarkers are needed to aid patient stratification for developing improved treatment strategies. We have investigated how type II collagen degradation products (CTX2), which are generated during OA, relate to MRI features of knee damage and patient reported pain. CTX2 was strongly related to synovitis and cartilage damage whereas reported pain was more strongly related to depression and BMI. CTX is thus complementary to pain scores as a marker of OA severity.

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Prevalence and Clinical Significance of Residual or Reconverted Red Bone Marrow on Knee MRI in Young Adults
Benny Antony1, Jasveen Kaur1, Tao Meng1, Alison Venn1, Flavia Cicuttini2, Lyn March3, Marita Cross3, Terence Dwyer4, Andrew Halliday5, Graeme Jones1, and Changhai Ding1

1Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia, 2Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia, 3Institute of Bone and Joint Research, University of Sydney, Sydney, Australia, 4Murdoch Childrens Research Institute, Melbourne, Australia, 5Radiology, Royal Hobart Hospital, Hobart, Australia

An abnormal distribution of residual or reconverted red bone marrow (RBM) has been identified on routine knee MRI. We aimed to identify the prevalence and the association between RBM and symptoms and structural abnormalities in a young population (n=327, aged 31-41 years). The presence of RBM in the distal femoral, proximal tibial and fibular metaphysis was graded based on the percentage of the metaphysis occupied (grade 0 to 3). Reconverted or residual RBM around the knee joint was present only among females and always involved the distal femoral region. RBM was associated with overweight measures and knee joint pain.

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Variation of ADC of skull bone marrow with age and pubertal status in a pediatric population
Erika Pace1,2, Andrew D Mackinnon2,3, and Nandita M deSouza1,2

1Cancer Research UK Imaging Centre, The Institute of Cancer Research, Sutton, United Kingdom, 2MRI Unit, The Royal Marsden Hospital NHS Foundation Trust, Sutton, United Kingdom, 3Department of Neuroradiology, Atkinson Morley Regional Neuroscience Centre, St George's University Hospitals NHS Foundation Trust, London, United Kingdom

ADC measurements were possible from the clivus of children. Values showed a significant negative correlation with age. Following puberty, there was a reduction in ADC and a left shift in centile histogram values, likely as a result of fat replacement. This was independent of gender. Bone marrow within the clivus behaves like marrow from tubular bones after puberty, and does not retain a cellular morphology expected from red hematopoietic bone marrow.

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Trabecular Bone Imaging Using a 3D Adiabatic Inversion Recovery Prepared Ultrashort Echo Time Cones (3D IR-UTE Cones) Sequence
Ya-Jun Ma1, Liang Li1, Yanjun Chen1, Saeed Jerban1, Michael Carl2, Eric Y Chang1,3, and Jiang Du1

1Radiology, University of California, San Diego, San Diego, CA, United States, 2GE health care, San Diego, CA, United States, 3VA San Diego Healthcare System, San Diego, CA, United States

The trabecular bone is both functionally and biomechanically important for vertebrates, including humans. Evaluation of trabecular bone provides important information about risk of both osteoporosis and bone fracture. Direct MR imaging of trabecular bone is difficult due to its ultrashort T2* and low water content, resulting in little or no signal when conventional pulse sequences are used. The purpose of this study was to develop and evaluate a 3D adiabatic inversion recovery prepared UTE Cones (3D IR-UTE-Cones) sequence for volumetric imaging of trabecular bone ex vivo and in vivo on a clinical 3T scanner in clinically acceptable scan times.

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Comparison of ZTE vs UTE for MR Bone Imaging
Michael Carl1, Yajun Ma2, Ricardo Mello2, Jiang Du2, and Eric Y Chang2,3

1General Electric, Global MR Applications & Workflow, San Diego, CA, United States, 2UCSD, San Diego, CA, United States, 3VA San Diego Healthcare System, San Diego, CA, United States

We compared different center-out 3D radial trajectories (ZTE and UTE) and assessed their advantages and disadvantages for bone imaging. We found that while ZTE and UTE show similar results at the same read BW, the higher BWs available with UTE can help reduce undesired background signals in the final bone images.

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Estimating the diagnostic value of IDEAL-IQ for vertebral compression fractures caused by osteoporosis and metastasis
Zhaolong Zheng1, Qingliang Niu2, Shasha Wu2, and Weiqiang Dou3

1Department of Radiology, WeiFang Traditional Chinese Hospital, Wei Fang, Shandong,P.R. China, China, 2WeiFang Traditional Chinese Hospital, Wei Fang, Shandong,P.R. China, China, 3GE Healthcare, MR Research China, Beijing, P.R. China, China

Traditional imaging methods are challenging to diagnose the vertebral compression fractures caused by osteoporosis and metastasis.  In this study, the iterative decomposition of water and fat with echo asymmetry and the least squares estimation quantification sequence (IDEAL-IQ)technique, as a novel fat quantification technique, was applied to quantitatively determine the bone marrow fat content for the patients with osteoporosis caused and metastasis caused vertebral compression fractures. We  found that the fat fraction (FF) and FF ratio of bone marrow fat in the vertebral body lesions of metastasis were significantly reduced compared with the acute compression fractures due to osteoporosis. Therefore, IDEAL-IQ has been proven an effective method for quantitative diagnosis of vertebral compression fractures.

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Discriminating between normal and cam positive hips using MRI texture and gradient-boosted decision trees
Rebecca E Thornhill1,2, Taryn Hodgdon1,2, Gerd Melkus1,2, Nick D James3, Paul E Beaulé4, and Kawan S Rakhra1,2

1Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada, 2Radiology, University of Ottawa, Ottawa, ON, Canada, 3Information Services, The Ottawa Hospital, Ottawa, ON, Canada, 4Division of Orthopaedic Surgery, The Ottawa Hospital, Ottawa, ON, Canada

Cam-type femoroacetabular impingement (FAI) results in altered biomechanics and acetabular pathology that has been associated with osteoarthritis of the hip. These early changes can be difficult to detect with routine clinical imaging. Texture analysis offers a more quantitative approach for characterizing gray-level patterns. The purpose of this study was to determine the MRI texture profile of acetabular subchondral bone in normal, asymptomatic cam positive and symptomatic cam-FAI hips with the assistance of gradient-boosted decision trees. This work demonstrates that MRI textural features can be used to generate machine learning models that can identify cam positive hips, regardless of symptom status.

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Optimal flip angle for imaging and T2* mapping of the human skull using ultra-short echo-time (UTE) imaging
Martin Krämer1, Benedikt Herzau1, and Jürgen R Reichenbach1,2,3,4

1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, 2Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, Germany, 3Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany, 4Center of Medical Optics and Photonics, Friedrich Schiller University Jena, Jena, Germany

To investigate the influence of the flip angle on imaging and T2* mapping of the human skull, multi-echo 3D ultra-short echo-time (UTE) imaging was performed for multiple flip angles ranging from 5° to 49°. Results based on difference images between two echoes indicate that higher flip angles are better suited for separating the skull from adjacent tissues. In addition, a strong dependency of the skulls T2* values on the flip angle was observed

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3D visualization of the cranial bone using fully automated segmentation based on ultra-short echo-time (UTE) imaging
Martin Krämer1, Benedikt Herzau1, and Jürgen R Reichenbach1,2,3,4

1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, 2Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, Germany, 3Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany, 4Center of Medical Optics and Photonics, Friedrich Schiller University Jena, Jena, Germany

To enable 3D-visualization of the cranial bone based on multi-echo ultra-short echo-time (UTE) data, a fully automated segmentation algorithm is presented. The algorithm concatenates several easy to implement processing steps while taking T2* maps calculated from three or more echoes or difference images calculated from the first two echoes of a UTE sequence as input. Comparison between a CT-based segmentation and the UTE-based segmentation showed very good agreement. The 3D visualization allowed easy assessment of the location and the course of cranial sutures as well as of diploic veins. 

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Quantitative Evaluation of Vertebral Marrow Fat content with Aging in Healthy Human using MRS and Dixon technique
Shao-Chieh Lin1, Hou-Ting Yang2, Yi-Jui Liu3, Hing-Chiu Chang4, Xiang-Wei Xie5, Wing P. Chang5, Yu-Chen Cheng1, and Yi-Zong Liou1

1Master 's Program of Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung City 407, Taiwan, 2Program of Electrical and Communications Engineering, Feng Chia University, Taichung City 407, Taiwan, 3Department of Automatic Control Engineering, Feng Chia University, Taichung City 407, Taiwan, 4Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, Hong Kong, Hong Kong, Hong Kong, 5Department of Radiology, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan, Taipei, Taiwan

Subjects with osteoporosis have increased fat marrow, and fat content also increases progressively in the normal aging people. Although MRS has shown the potential probing the bone marrow content characteristics of the vertebra body in previous studies, all of them were a ROI analysis and loss local information. The purposes of this study were using MRS and Dixon technique to investigate the change of fatty marrow content with aging in human vertebra body. Our results have demonstrated the water-fat separation could quantitate vertebral marrow adiposity, which will be a potential method to provide local information for osteoporosis-related research fields. 

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Evaluating Gadolinium Deposition in Rabbit Cortical Bone by Using Ultrashort Echo Time T1 Mapping: Preliminary Results
Kaixuan Zhao1, Shisi Li2, Yingjie Mei1,3, Qinqin Yu2, Keyan Yu2, Cuiling Zhu2, Jian Wang2, Hanwen Deng1, Xiaodong Zhang2, Jiang Du4, and Yanqiu Feng1

1School of Biomedical Engineering, Guangdong Provincial Key Laborary of Medical Image Processing, Southern Medical University, Guang Zhou, China, 2Imaging department of Southern Medical University affiliated the third hospital, Guang Zhou, China, 3Philips Healthcare, Guang Zhou, China, 4Department of Radiology, University of California San Diego, San Diego, California., San Diego, CA, United States

Gadolinium based contrast agents (GBCA) injection for enhanced MRI can induce gadolinium deposition in bones. In this work we investigated the feasibility of evaluating gadolinium deposition in rabbit cortical bone by using ultrashort echo time (UTE) T1 mapping at 7T. Lower T1 values were observed in the GBCA injection group than those in the control group (341±17.6ms vs. 450±10ms). This preliminary result indicates that UTE T1 mapping may be a feasible technique for evaluating bone gadolinium deposition.

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HIGH RESOLUTION IMAGING AND QUANTIFICATION OF VASCULATURE WITHIN CORTICAL BONE POROSITY USING DCE-MRI AND HR-pQCT
Matthew Gibbons1, Po-hung Wu1, Sarah Foreman1, Misung Han1, Roland Krug1, Jing Liu1, Thomas Link1, and Galateia Kazakia1

1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States

Cortical bone porosity is a major determinant of bone strength. However, the causes of pathological pore growth are not well understood. The prevalence of blood vessels or marrow fat in pores may serve as an indicator for vessel- or marrow-driven processes. We present an algorithm to combine high resolution CT for pore identification and dynamic contrast enhanced MRI for blood vessel identification. Using this algorithm, imaged vessels are associated with specific pores and pore content is quantified.

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Vertebral bone marrow fat content changes in postmenopausal women receiving combined aromatase inhibitor and bisphosphonate therapy after one year
Michael Dieckmeyer1,2, Stefan Ruschke2, Alexander Rohrmeier2, Jan Syväri2, Ingo Einspieler2, Jan S. Kirschke1, Ernst J. Rummeny2, Claus Zimmer1, Dimitrios C. Karampinos2, and Thomas Baum1

1Department of Diagnostic and Interventional Neuroradiology, Technical University of Munich, München, Germany, 2Department of Diagnostic and Interventional Radiology, Technical University of Munich, München, Germany

In recent years in-vivo assessment of vertebral bone marrow (VBM) fat composition has been increasingly used in the investigation of osteoporosis and bone metabolism. Postmenopausal women represent a population of particular interest because they are at higher risk for osteoporosis resulting from estrogen deficiency which can be potentially aggravated by aromatase inhibitor (AI) therapy. The present study demonstrated a relative increase in vertebral bone marrow fat content quantified by chemical shift encoding-based water-fat MRI in patients receiving simultaneous AI and bisphosphonate (BP) therapy, contradicting previous findings reported in the literature.

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Research on the feasibility of MR imaging of patients receiving anterior cervical surgery using MAVRIC SL-STIR sequence at 3T
Renjie Yang1, Yunfei Zha1, Yu Zhang1, and Yang Fan2

1Renmin Hospital of Wuhan University, Wuhan, China, 2GE Healthcare, Beijing, China

Metal implants are now very common in modern joint and spine surgeries. However, conventional MR images are significantly compromised by implant-induced magnetic susceptibility artifacts. A novel metal artifacts reduction technique, termed MAVRIC SL was proposed. The purpose of this study is to evaluate its clinical feasibility and diagnostic value in patients after anterior cervical surgery compared with routine 2D FSE sequence at 3T. As a result, although the image quality of MAVRIC SL is limited at 3T, it can still provide important additional diagnostic information through substantially reduced metal artifacts.

1306
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Value of zero echo time imaging and CT in diagnosis of bone destruction of bone tumors and tumor-like lesions
Liping Shi1, Nianyun Li1, Jie Meng1, Han Wang1, Yong Zhang2, Bing Wu2, and Yanhong Xu1

1Radiology, Shanghai General Hospital, Shanghai, China, 2GE Healthcare, Shanghai, China

The purpose of the study was to evaluate the clinical applicability of zero echo time (ZTE) MR and compare the image quality between CT and ZTE imaging of bone tumor and tumor-like lesions. Thirty-six patients including 18 males and 18 females were recruited to undergo ZTE MR and CT. Agreement was assessed between raters and Weight Kappa statistics were performed. The difference of image quality between ZTE and CT imaging were not significant. Our results confirm that ZTE MR imaging provides accurate imaging of bone morphology with CT-like contrast that is not available with standard MR sequences.

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Evaluation of the effects of age and gender on water-fat composition of the lumbar vertebral bone marrow with magnetic resonance IDEAL-IQ sequence
QING FAN1, HUIPENG REN1, XIAOHU WANG1, LINGYUN SUO1, and Xiaocheng Wei2

1Baoji Center Hospital, Baoji, China, 2GE Healthcare China, Beijing, Christmas Island

This study revealed the proton density fat fraction (PDFF) of lumbar vertebral bone marrow in different age groups and gender of normal adults using iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL) technique. We demonstrated significant differences of lumbar vertebral bone marrow PDFF across three age groups. Particularly, the highest PDFF was found in the oldest group. We also found a moderate positive correlation between age and PDFF, while the correlation was higher in female than in male. Taken together, our findings pave the way for exploring age-related lumbar vertebral diseases and metabolic disorders.

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7T Arterial Spin Labeling Imaging of Epiphyseal Bone Marrow in Distal Femoral Condyle – A Feasibility Study
Xiufeng Li1, Casey Johnson1, and Jutta Ellermann1

1Radiology-Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

Perfusion imaging of epiphyseal bone marrow in the distal femoral condyle can provide valuable insights into the pathophysiological mechanism of knee injuries or diseases, and has a great potential to facilitate the management of developmental knee diseases. A previous study at 3T indicated that low perfusion signal-to-noise ratio (SNR) imposed a great challenge to achieve high-quality bone marrow arterial spin labeling (ASL) images. 7T can benefit ASL imaging due to greatly increased blood T1 and imaging SNR. The presented study evaluated the feasibility and challenges of epiphyseal bone marrow ASL imaging in the distal femur at 7T.


Cartilage 1

Exhibition Hall
Monday 8:15 - 9:15
 Musculoskeletal

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Transfer Learning in Hip MRI Segmentation: Geometry Is More Important Than Contrast
Claudia Iriondo1,2, Michael Girard3, Valentina Pedoia1, and Sharmila Majumdar1

1Radiology and Biomedical Imaging, University of California, San Francsico, San Francisco, CA, United States, 2Bioengineering, University of California, Berkeley, Berkeley, CA, United States, 3Center for Digital Health Innovation, University of California, San Francsico, San Francisco, CA, United States

Transfer learning for medical image segmentation tasks is a promising technique that has the potential to overcome the challenges posed by limited training data. In this study we investigate the contribution of geometrically-similar and contrast-similar features for transfer learning to a hip MR segmentation task. We show pretraining with a geometrically similar task leads to more rapid convergence, can stabilize segmentation accuracy as datasets become reduced in size, and leads to more reliable biomarker extraction.

1310
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BEES Knees: Bilateral Expedited Exam Supporting Quantitative Imaging of Knees
Emma Bahroos1, Radhika Tibrewala1, Misung Han1, Bruno Astuto Arouche Nunes1, Valentina Pedoia1, and Sharmila Majumdar1

1Radiology, UCSF, San Francisco, CA, United States

Osteoarthritis (OA) is a degenerative joint disease that commonly affects bilateral joints. This study combined simultaneous bilateral knee MRI with an automatic image processing for faster acquisition to image biomarker extraction.  Simultaneous bilateral knee MRIs of 5 healthy volunteers was compared to singularly acquired knee images. Isotropic 3D CUBE FSE were used to automatically segment cartilage.  Voxel based relaxometry from 3D combined T1ρ/T2 was evaluated for both types of acquisition. Our results show the ability of dual coil configuration allows for high resolution isotropic images, while also retaining the accuracy of quantitative data when compared to singly acquired bilateral knees.

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Quantitative Articular Cartilage Assessment in Patients with Juvenile Osteochondritis Dissecans (JOCD) at 3T MRI
Kai D. Ludwig1, Casey P. Johnson1,2, Stefan Zbyn1,2, Shelly Marette2, Takashi Takahasi2, Jeffrey A. Macalena3, Bradley J. Nelson3, Marc A. Thompkins3, Cathy S. Carlson4, and Jutta M. Ellermann1,2

1Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, United States, 2Radiology, University of Minnesota, Minneapolis, MN, United States, 3Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States, 4Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, United States

Juvenile osteochondritis dissecans (JOCD) is a disease affecting the knee joint of young active patients that can lead to early osteoarthritic changes. JOCD lesions are formed deep to the articular cartilage with late changes in the overlying articular cartilage. Our study was motivated by clinical observations that the opposing articular cartilage might be affected early. In this study, we observed a significant increase in T2* relaxation times in the articular cartilage of the medial tibia directly opposing the lesions when compared to the control region on the lateral site. These findings might indicate compositional changes in the tibial cartilage matrix due to increased biomechanical loading. Further study of T2* mapping as a potentially clinically realizable method to stage and prognosticate JOCD are warranted.

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Diffusion Tractography of the Rat Knee at Microscopic Resolution
Nian Wang1, Gary Cofer1, Yi Qi1, and G. Allan Johnson1

1Center for In Vivo Microscopy, Department of Radiology, Duke University, Durham, NC, United States

Application of DTI to map the complex collagen fibril structures in preclinical studies of the knee joint is still challenging, due to the limited spatial resolution previously used, relative low FA values, and relatively low signal-to-noise (SNR). We imaged the rat knees in a preclinical 9.4 T system with powerful gradients (2000 mT/m) to minimize TE. A modified 3D diffusion-weighted spin-echo pulse sequence was used to achieve isotropic spatial resolution at microscopic scale. 

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Assessment of the Angular Dependence of 3D Ultrashort Echo Time Cones Adiabatic T1ρ (3D UTE-Cones-AdiabT1ρ) Imaging
Mei Wu1,2, Yajun Ma1, Lidi Wan1, Tan Guo1, Saeed Jerban1, Hyungseok Jang1, Eric Y Chang1,3, and Jiang Du1

1Department of Radiology, University of California, San Diego, San Diego, CA, United States, 2Department of Radiology, Guangzhou First People’s Hospital, School of Medicine, South China University of Technology, Guangzhou, China, 3Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

In this study we aimed to evaluate the magic angle sensitivity of the 3D UTE-Cones-AdiabT sequence in imaging the cadaveric human Achilles tendon and patellar cartilage samples on a clinical 3T scanner. The 3D UTE-Cones-AdiabT shows much reduced magic angle effect than regular T and T2*. The superficial layers show reduced magic angle effect compared to the middle and deep layers of articular cartilage. The 3D UTE-Cones-AdiabT sequence may provide magic angle insensitive evaluation of all the major knee joint tissues, thus providing a truly “whole-organ” approach for more accurate diagnosis of early OA.

1314
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T1ρ at low spin-lock amplitudes is more sensitive to degenerative changes in articular cartilage
Abdul Wahed Kajabi1,2, Victor Casula1,2, Juuso Ketola1, Jaakko K. Sarin3,4, Irina A.D. Mancini5, Jetze Visser5, Harold Brommer5, P. René Van Weeren5, Jos Malda5,6, Juha Töyräs3,4,7, Mikko J. Nissi3,4, and Miika T. Nieminen1,2,8

1Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, 2Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland, 3Department of Applied Physics, University of Eastern Finland, Kuopio, Finland, 4Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland, 5Department of Equine Sciences, Utrecht University, Utrecht, Netherlands, 6Department of Orthopaedics, University Medical Center Utrecht, Utrecht, Netherlands, 7School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, 8Department of Diagnostics Radiology, Oulu University Hospital, Oulu, Finland

In this study, continuous wave T scans at various spin-lock amplitudes (γB1 = 100, 200, 300, 400, 500, 600, 800, 1000 and 2000 Hz) were utilized to evaluate multiple articular cartilage regions at increasing distances from a surgically induced lesion in equine specimens. Significant differences were observed between regions adjacent and distant to the lesion, and the differences between the compared sites were larger at lower spin-lock amplitudes. The variations were in agreement with biomechanical properties (determined via indentation testing) of the regions. The findings suggest that T at low spin-lock amplitudes is more responsive to progressive alterations in articular cartilage.

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UTE-based adiabatic T1ρ is sensitive to enzymatic proteoglygan degradation in human articular cartilage
Lidi Wan1,2, Adam C Searleman1, Yajun Ma1, Jonathan H Wong3, Mark E Murphy4, Jiang Du1, Guangyu Tang2, and Eric Y Chang1,3

1Department of Radiology, UC San Diego, San Diego, CA, United States, 2Department of Radiology, Shanghai Tenth People's Hospital of Tongji University, Shanghai, China, 3Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States, 4Orthopaedic Surgery Service, VA San Diego Healthcare System, San Diego, CA, United States

A series of quantitative UTE techniques have been developed to assess articular cartilage. The early stage of osteoarthritis is characterized by proteoglycan (PG) loss in cartilage. This study aimed to determine if quantitative UTE-based biomarkers are sensitive to PG loss induced by chondroitinase ABC in cadaveric human cartilage. Pure cartilage wafers were exposed to sequential enzymatic digestion. MR imaging was performed before and after sequential digestion. PG loss was observed after digestion, with a corresponding increase in UTE adiabatic T1ρ values as compared to controls.

1316
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Cartilage T2 Mapping of the Knee Using Fast Spin-Echo Multi-Band Acceleration
Robert Moskwa1, Fang Liu1, Graeme McKinnon2, Rob Peters2, and Richard Kijowski1

1Radiology, University of Wisconsin, Madison, WI, United States, 2Applied Science Laboratory, GE Healthcare, Waukesha, WI, United States

A T2 mapping sequence was performed in the axial and sagittal planes with multi-band (MB) acceleration (T2-MB) and without MB acceleration (T2) on the knees of seven healthy volunteers and three subjects with knee osteoarthritis at 3.0T.  The use of MB acceleration provided a 50% reduction in scan time.  The T2 and T2-MB sequences showed very similar pixel-by-pixel patellar cartilage T2 values in the axial plane and very similar regional knee joint cartilage T2 values in the sagittal plane for all subjects.  However, there was a slight bias toward lower cartilage T2 values when using MB acceleration.

1317
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Quantitative hip cartilage MRI of patients with hip dysplasia: Evaluation of dGEMRIC, T1ρ and T2* mapping
Gerd Melkus1,2, Paul E Beaulé3,4, Geoffrey Wilkin3,4, and Kawan Rakhra1,2

1Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada, 2Radiology, University of Ottawa, Ottawa, ON, Canada, 3Division of Orthopaedic Surgery, The Ottawa Hospital, Ottawa, ON, Canada, 4Medicine, University of Ottawa, Ottawa, ON, Canada

Developmental dysplasia of the hip is a common risk factor of early osteoarthritis. Knowledge of the molecular health of cartilage using quantitative MR methods could diagnose and stage the disease and may also allow for treatment stratification. In this study, we evaluated and compared three different biochemical sensitive MR methods (dGEMRIC, T1ρ and T2*) for cartilage imaging on patients with developmental dysplasia of the hip. Quantitative T1ρ as well as T2* mapping of the hip cartilage correlated significantly with the dGEMRIC method and could possibly replace the contrast-based method.

1318
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Longitudinal T1ρ mapping of contralateral hip in patients with unilateral cam-type femoroacetabular impingement (FAI)
Gerd Melkus1,2, Kawan Rakhra1,2, and Paul E Beaulé3,4

1Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada, 2Radiology, University of Ottawa, Ottawa, ON, Canada, 3Division of Orthopaedic Surgery, The Ottawa Hospital, Ottawa, ON, Canada, 4Medicine, University of Ottawa, Ottawa, ON, Canada

Cam-type femoroacetabular impingement (FAI) is a major cause of hip osteoarthritis. Quantitative T1ρ MRI has the potential to detect early cartilage degeneration due to its sensitivity to proteoglycan. In this study we performed longitudinally (124 days (average) after surgery and 4.8 years (average) follow up) T1ρ mapping in patients with bilateral (symptomatic and asymptomatic) cam-type FAI on the asymptomatic side after the symptomatic cam-FAI was surgically corrected. The cartilage of the contralateral hip did not show significant proteoglycan depletion and therefore no further degeneration between the initial and the follow up scan was detected. The contralateral hips remained stable.

1319
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Multiple-echo steady-state (MESS): Simultaneous water-fat separation, $$$T_2$$$, $$$T_2^{'}$$$, and $$$T_2^*$$$ mapping in the knee at 3 tesla
Frank Zijlstra1 and Peter R Seevinck1

1Image Sciences Institute, UMC Utrecht, Utrecht, Netherlands

This study proposes an extension of the double-echo steady-state (DESS) sequence to include multiple readouts. This multiple-echo steady-state (MESS) sequence supports quantification of water, fat, $$$T_2$$$, $$$T_2^{'}$$$, and $$$T_2^*$$$ in a single, efficient acquisition. These parameters may provide additional tissue-specific MRI biomarkers for early detection and grading of osteoarthritis (OA), on top of the $$$T_2$$$ quantification of cartilage provided by the DESS sequence. In vivo results show that parameter quantification using MESS corresponds well with quantification on water-selective DESS images.

1320
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Evaluating the Relationship Between gagCEST MRI and Cartilage Biochemical Composition in Juvenile Bovine Articular Cartilage
Lauren Watkins1, Feliks Kogan2, Elka Rubin2, Marianne Black3, Marc Levenston2,3, and Garry Gold2

1Bioengineering, Stanford University, Stanford, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3Mechanical Engineering, Stanford University, Stanford, CA, United States

Chemical exchange saturation transfer of glycosaminoglycans (gagCEST) is a quantitative MR technique with potential for detecting early changes in cartilage composition. However, its relationship to tissue glycosaminoglycan (GAG) content has not yet been validated using standard biochemical assays. Here, we examine the relationship between gagCEST at 3T and 7T to cartilage biochemical properties using immature bovine femoral cartilage. Comparison of deep and superficial gagCEST asymmetry maps suggest that while gagCEST reflects the laminar differences in biochemical GAG composition, there is a weak correlation between gagCEST asymmetry and GAG content at 7T and 3T.  

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Assessment of Cartilage pH Using AcidoCEST-UTE MRI at 3T with Histological Correlation
Rachel High1,2, Yajun Ma2, Qingbo Tang2,3, Jonathan Wong2,3, Lidi Wan2, Jiang Du2, and Eric Y Chang2,3

1University of Arizona, Tucson, AZ, United States, 2Department of Radiology, University of California San Diego, San Diego, CA, United States, 3Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

The poor correlation between structural abnormalities of osteoarthritis (OA) and OA pain complicates treatment and pain management. Acidosis is heavily implicated in pain, and thus may be used to identify areas of pain not associated with structural damage. In this study, we used a pH-sensitive imaging method known as chemical exchange saturation transfer (acidoCEST) MRI to assess acidosis in cadaveric cartilage tissue and assess the relationship between pH and osteochondral vascularity as determined on histology. We show that acidoCEST MRI can measure extracellular pH (pHe) in cartilage, enabling further studies into the complex relationship between acidification, osteochondral channels, and pain. 

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Detecting Early Changes in ACL-Reconstructed Knee Cartilage: Cluster Analysis of T2 Relaxation Times in Superficial and Deep Cartilage and ADC Analysis
Marianne Black1,2, Daehyun Yoon2, Kate Young2, Akshay S. Chaudhari2, Feliks Kogan3, Garry Evan Gold2,4,5, Marc Elliot Levenston1,2,5, and Brian Hargreaves2,5,6

1Mechanical Engineering, Stanford University, Stanford, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3Stanford University, Stanford, CA, United States, 4Orthopedic Surgery, Stanford University, Stanford, CA, United States, 5Bioengineering, Stanford University, Stanford, CA, United States, 6Electrical Engineering, Stanford University, Stanford, CA, United States

ACL-injured subjects are at an increased risk of developing osteoarthritis. There is a need to detect early osteoarthritic changes for the development of treatments that can slow or stop osteoarthritis progression. T2 and ADC are considered reflective of the structure and composition of cartilage, and may be valuable for detecting early osteoarthritis. This study used two qDESS acquisitions to obtain T2 and ADC maps in 10 ACL-reconstructed subjects and 10 controls 3-weeks, 3-months and 9-months post-surgery. Our results show that T2 cluster analysis was able to detect changes to the ACL-reconstructed knee as early as 3-months post-surgery.

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T1ρ Relaxation of Human Articular Cartilage Using Time-fractional Order Model
Lixian Zou1,2, Haifeng Wang1, Yuanyuan Liu1, Weitian Chen3, Yanjie Zhu1, Dong Liang1,4, and Xin Liu1

1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Shenzhen, China, 3Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, HongKong, China, 4Research Center for Medical AI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China

T imaging is a promising non-invasive diagnostic tool for early detection of articular cartilage degeneration. A mono-exponential model is normally used to describe the T relaxation process. However, mono-exponentials may not adequately to describe NMR relaxation in complex, heterogeneous, and anisotropic materials, such as articular cartilage. Fractional-order models have been successfully used to describe complex relaxation phenomena in the laboratory frame in cartilage matrix components. In this work, we develop a time-fractional order (T-FACT) model to analyze T relaxation in human articular cartilage. The results show the proposed method can better represent the T relaxation in human articular cartilage.

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ARCADE: An efficient anisotropic $$$R_2$$$ relaxation mapping for human knee cartilage at 3T
Yuxi Pang1, Riann Palmieri-Smith2, Dariya Malyarenko 1, and Scott Swanson1

1Department of Radiology, University of Michigan, Ann Arbor, MI, United States, 2School of Kinesiology and Department of Orthopedic Surgery, University of Michigan, Ann Arbor, MI, United States

Water proton $$$R_2$$$ relaxation in cartilage at 3T contains both an isotropic and an anisotropic contributions, with the latter being more sensitive to degenerative changes. A composite relaxation ($$$R_2-R_{1ρ}$$$) mapping could be used to separate two contributions; however, its lengthy protocol had prevented it from being adopted in clinical applications. Here, we propose an efficient alternative based on a single T2W sagittal image to isolate an anisotropic $$$R_2$$$ and compare it with $$$R_2-R_{1ρ}$$$ on five live human knees. The comparable results demonstrate that the developed method could be easily used in clinical studies to characterize anisotropic $$$R_2$$$ of articular cartilage.

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Toward an orientation-independent MR relaxation metric from $$$R_{1ρ}$$$ dispersion in articular cartilage
Yuxi Pang1

1Department of Radiology, University of Michigan, Ann Arbor, MI, United States

Residual dipolar interaction is the dominant mechanism for $$$R_2$$$ relaxation in cartilage, leading to the well-known "magic angle effect" observed in clinical MR imaging that makes reliable diagnostics challenging. Here, we show that the orientation-dependent factor in $$$R_2$$$ could be eliminated by a correlation time $$$τ_b$$$ derived from $$$R_{1ρ}$$$ dispersion in terms of order parameter. This predication was tested on orientated bovine patellar cartilage specimens at 9.4T and on one live human knee at 3T. The preliminary data showed that the derived anisotropic $$$R_2$$$ and $$$τ_b$$$ had respectively significantly high and moderate positive correlations in good agreement with the predication.

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Simultaneous image super-resolution and contrast synthesis techniques applied to routine clinical magnetic resonance images of the knee for advanced automated processing of joint cartilage
Ales Neubert1, Pierrick Bourgeat1, Jose Manjon2, Craig Engstrom3, Shekhar S Chandra3, Stuart Crozier3, and Jurgen Fripp1

1AeHRC, CSIRO, Brisbane, Australia, 2ITACA institute, Universidad Politécnica de Valencia, Valencia, Spain, 3University of Queensland, Brisbane, Australia

While high resolution 3D MR images are well suited for automated cartilage segmentation in the human knee joint, they are not routinely acquired in clinical practice which limits opportunities for reliable segmentation of cartilage using automated algorithms. We propose a neural network for generating synthetic MR images with enhanced contrast and higher spatial resolution from routine, low resolution clinical knee scans. Segmentation results showed that accurate cartilage segmentation can be obtained using the synthesised images.

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Localization of the bright ultra-short echo time MRI signal at the osteochondral interface
Olli Juhani Nykänen1, Henri Leskinen1, Mikko Finnilä1,2, Sakari Karhula2, Simo Saarakkala2,3, and Mikko J Nissi1,2

1Department of Applied Physics, University of Eastern Finland, Kuopio, Finland, 2Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, 3Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland

In this study, we investigated the bright signal feature that has been observed at the bone-cartilage interface using ultrashort echo time imaging sequences. We used micro-CT imaging of the same specimens to locate the origin of the signal in SWIFT-MRI images. The results indicated that the bright signal originates from the deep non-calcified cartilage region instead of the calcified cartilage, which has been previously hypothesized to be part of the signal location. The physiological origin of this signal as well as its role in the diagnosis of osteoarthritis remains to be evaluated.

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Diagnostic performance of three-dimensional fast-spin echo(3D MATRIX) accelerated with compressed sensing(CS) for internal injury of the knee
Yakui Wang1, Xiao Jin1, Qiang Zhao1, Ning Lang1, and Huishu Yuan1

1Peking University Third Hospital, Beijing, China

    We aimed to evaluate the diagnostic performance of a three-dimensional fast-spin echo(3D MATRIX) accelerated with compressed sensing(CS) for internal injury of the knee joint.Sixty-two knee joints with trauma were examined at 3T MRI system including conventional 2D FSE protocol and 3D MATRIX before arthroscopic operations. Signal-to-noise ratio(SNR), contrast signal-to-noise ratio(CNR) and diagnostic performance were compared between two sequences. We found that 3D MATRIX had significantly higher SNR and CNR, and provided higher sensitivity but lower specificity for diagnosing cartilage injury compared to conventional 2D FSE. And the two sequences had similar diagnostic performance for ACL and meniscus tear.

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Comparison of Single-Component and Multi-Component T2 Parameters and Mechanical Parameters of Human Patellar Cartilage at 3.0T
Matthew Grondin1, Fang Liu2, Michael Vignos1, Jiang Du3, Corrinne Henak1, and Richard Kijowski2

1Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, United States, 2Radiology, University of Wisconsin-Madison, Madison, WI, United States, 3Radiology, University of California-San Diego, San Diego, CA, United States

Multi-component Driven Equilibrium Single Pulse Observation of T1 and T2 (mcDESPOT) was used to measure single-component T2 relaxation time (T2Single) and the fraction of the fast relaxing macromolecular bound water component (FF) of 24 human patellar cartilage samples at 3.0T.  The cartilage samples underwent unconfined compression testing to measure linear modulus and energy dissipation at 0.01Hz and 10Hz.  There were low and marginally statistically significant (p=0.052-0.084) negative correlations between T2Single and linear modulus and energy dissipation.  There were moderate and statistically significant (p<0.002) positive correlations between FF and linear modulus and energy dissipation. 

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MRI texture analysis of vertebral subchondral bone
Feifei Zeng1, Yunfei Zha2, and Yang Fan3

1Radiology, Renmin Hospital of Wuhan University, Wuhan, China, 2Renmin Hospital of Wuhan University, Wuhan, China, 3GE Healthcare China, Bejing, China

The purpose of this study is to assess the feasibility of MRI texture analysis as a method of quantifying vertebral subchondral bone (VSB) in early intervertebral disk degeneration (IDD). Sagittal T1WI, T2WI and T2* mapping images of lumbar vertebra were scanned at 3T MRI. Texture parameter values(mean, variance, skewness, correlation and entropy) of VSB (on T1WI) and T2* value of CEP were used for statistical evaluations. It was found that Significant differences in VSB texture parameters (mean ,variance and entropy) and T2* value of CEP were demonstrated between groups at the cephalic and caudal. Accordingly, texture parameter-mean showed significantly higher diagnostic accuracy than other texture parameters (variance and entropy) and T2* value for differentiating early IDD. MRI texture analysis can be used to assess human lumbar early IDD.

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gagCEST effect strongly depends on GAG molecular composition
Emma Olsson1, Pernilla Peterson1, André Struglics2, Michael Gottschalk3, Patrik Önnerfjord4, and Jonas Svensson1,5

1Medical Radiation Physics, Department of Translational Medicine, Lund University, Malmö, Sweden, 2Orthopaedics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden, 3Lund University Bioimaging Center, Lund University, Lund, Sweden, 4Rheumatology and Molecular Skeletal Biology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden, 5Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden

gagCEST has been suggested as a method for in vivo evaluation of cartilage GAG content. The main type of GAG in cartilage is chondroitin sulfate (CS), most commonly CS-A and CS-C. Validation of gagCEST have mostly been performed using CS-A but the main type in mature human articular cartilage is CS-C. In this study we evaluate the gagCEST effect from GAG in different forms. Our results indicate that mainly CS-A is contributing to gagCEST effect in cartilage, while no or little effect is seen from CS-C. gagCEST may therefore not correctly reflect the GAG content of human articular cartilage. 

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Rapid Quantitative Simultaneous Bilateral Knee Imaging with Fully Automated Femoral Cartilage Analysis: Toward Knee Asymmetry Evaluation.
Marco Barbieri1,2, Arjun D. Desai2, Feliks Kogan2, Valentina Mazzoli2, Elka Rubin2, Gastone Castellani1, Garry E. Gold2,3, Brian A. Hargreaves2,3,4, and Akshay S. Chaudhari2

1Department of Physics and Astronomy, University of Bologna, Bologna, Italy, 2Department of Radiology, Stanford University, Stanford, CA, United States, 3Department of Bioengineering, Stanford University, Stanford, CA, United States, 4Department of Electrical Engineering, Stanford University, Stanford, CA, United States

Quantitative bilateral knee MRI and whole femoral cartilage analysis is currently limited by costs and scan time. We propose a rapid, simultaneous bilateral knee MRI protocol followed by a fully automated pipeline to perform quantitative T2 analysis of the whole femoral cartilage plate of both knees. Five healthy subjects and a subject with an ACL reconstruction were scanned in this study and the results demonstrated high scan-rescan repeatability and a good agreement between manual and automatic segmentation. The proposed acquisition method with automated analysis may make bilateral imaging more feasible and efficient for use in longitudinal and cross-sectional studies.

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Short-Term Effects of Running on T2 Relaxation Times of Femoral Cartilage in Female Runners
Hollis A Crowder1, Valentina Mazzoli2, Marianne Black1, Lauren Watkins3, Feliks Kogan2, Brian Hargreaves2,4, Marc Levenston1,3, and Garry Gold2,3

1Mechanical Engineering, Stanford University, Palo Alto, CA, United States, 2Radiology, Stanford University, Palo Alto, CA, United States, 3Bioengineering, Stanford University, Palo Alto, CA, United States, 4Electrical Engineering, Stanford University, Palo Alto, CA, United States

This study tracks changes in water content in femoral cartilage from running by comparing T2 relaxation times of cartilage at baseline, time 0, and time 60 minutes post-run. Significant decreases in T2 relaxation times between baseline and time 0/time 60 minutes post-run scans occurred in superficial and deep cartilage, and a significant increase in T2 relaxation time occurred between time 0 and time 60 minutes post-run scans in deep cartilage, suggesting a reduction and partial recovery of cartilage water content. This study demonstrates the high sensitivity of T2 to cartilage loading patterns during running and supports the potential of using this setup as a method for identifying early changes in cartilage health.


Muscle 2 & Other MSK

Exhibition Hall
Monday 8:15 - 9:15
 Musculoskeletal

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Evaluation of input data and UNet based convolutional network architectures for automated muscle annotation in 2D and 3D
Martijn Froeling 1, Lara Schlaffke2, Marlena Rohm2, Ivana Isgum3, Hermien E Kan4, and Jelmer M Wolterink3

1Department of Radiology, University medical center utrecht, Utrecht, Netherlands, 2Department of Neurology BG, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany, 3Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 4Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands

Manual annotation of muscle is still one of the most time-consuming steps in skeletal muscle MRI research. In this study we have investigated three aspects of automated muscle annotation using deep convolutional networks. First, we directly compare five different network architectures. Second, we compare the effect of providing various input data all based on Dixon imaging. Third, we investigate the effect of the amount of training data provided to the network. In summary we found that UNet-like convolutional networks allow for accurate and precise annotation of calf muscle in 2D and 3D and that the data provided is the strongest predictor of success.

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Assessing diffuse muscle fibrosis by ECV estimation, T1 and T2 relaxometry in a non-dystrophic murine model
Aurea Martins Bach1, Ericky C. A. Araujo1, Julien Le Louër1, Jean Marc Boisserie1, Yves Fromes1, and Pierre G. Carlier1

1NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, CEA/DRF/IBFJ/MIRCen, Paris, France

Skeletal muscle fibrosis, a key pathological feature in muscle disorders, is still inaccessible by NMR. In this study, we investigated the effects of diffuse muscle fibrosis on T2, natT1, and extracellular volume (ECV, estimated from muscle and plasma T1 pre and post-Gd injection). In order to reduce interfering effects with fibrosis, we developed a new non-dystrophic mouse model with increased muscle fibrosis, but limited levels of inflammation and no fat infiltration. A positive correlation between ECV and collagen content could be observed. Collagen content presented a weak positive correlation with T1, and a weak but significant negative correlation with T2.

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Longitudinal Analysis of Spontaneous Mechanical Activities in Resting Leg Musculature Assessed by Diffusion-Weighted Imaging: Preliminary Results
Martin Schwartz1,2, Günter Steidle1, Petros Martirosian1, Thomas Küstner1,2,3, Jürgen Machann1,4,5, Anja Böhm4,5,6, Cora Weigert4,5,6, Bin Yang2, and Fritz Schick1

1Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Tübingen, Germany, 2Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, 3School of Biomedical Engineering & Imaging Sciences, King’s College London, St. Thomas’ Hospital, London, United Kingdom, 4Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany, 5German Center for Diabetes Research (DZD), Tübingen, Germany, 6Department of Endocrinology and Diabetology, Angiology, Nephrology and Clinical Chemistry, University Hospital Tübingen, Tübingen, Germany

Accurate quantification and grading of spontaneous mechanical activity of musculature of healthy and non-healthy subjects as measurable by single-shot diffusion-sensitive MRI requires certain long-term stability in order to reflect changes in the underlying muscular condition. Up to now, no longitudinal studies have been conducted, thus short- as well as long-term variation in the same subject under examination is unknown. This work examines the impact of the time of day when the examination takes places as well as long-term changes over 23-62 months in several subjects.

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IVIM imaging of muscle following moderate and high-intensity exercise
Erin K Englund1, David B Berry2, Samuel R Ward1,3, Lawrence R Frank3, and Bahar Shahidi1

1Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA, United States, 2Department of Nanoengineering, University of California San Diego, La Jolla, CA, United States, 3Department of Radiology, University of California San Diego, La Jolla, CA, United States

IVIM imaging provides insight into microvascular blood flow. Here, we investigate IVIM parameters following moderate and high-intensity exercise protocols, activating the plantar flexors and dorsiflexors of the leg. By interleaving b=0 images throughout the diffusion-weighted acquisition, we were additionally able to evaluate T2 changes following exercise. We observed an increase in T2 and diffusion coefficient, D, following high-intensity exercise. Changes were less obvious following moderate-intensity exercise. 

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Pulse sequence and reconstruction methods for extraction of spatial variation in multicomponent T2 relaxation for diagnosis of fluid and muscle disorders
Ashvin Bashyam1,2, Chris J Frangieh1,2, and Michael J Cima2,3

1Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2David H. Koch Institute For Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States, 3Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States

Significant unmet diagnostic need exists for diseases characterized by changes in T2 relaxation properties of tissue, especially those related to changes in fluid volume status and muscle disorders. Current methods for quantifying these disorders, such as MRI, are resource-intensive limiting widespread adoption. We introduce a novel method of quantitative tissue separation using single-sided magnetic resonance sensors. We explore pulse sequences and fitting techniques to characterize distinct tissue compartments in heterogeneous samples. We then extend these techniques to in vitro and in vivo models, and we finally apply them to measure the progression of acute muscle edema in an animal model.

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Fatty infiltration of paraspinal muscles is associated with bone mineral density of lumbar spine
xiaodong zhang1, Yinxia Zhao1, Mingqian Huang2, Shaolin Li3, and Chuan Huang2

1The Third Affiliated Hospital of Southern Medical University (Orthopaedic Hospital of Guangdong Province), guangzhou, China, 2Stony Brook Medicine, Stony Brook, NY, United States, NY, NY, United States, 3The Fifth Affiliated Hospital of Sun Yet-sen Univeristy, zhuhai, China

Paraspinal muscle fatty infiltration (FI) is an important factor affecting spinal function. However, there is no previous study investigating the relationship between paraspinal muscle FF and spinal BMD. Our study demonstrated that fat fractions of erector spinae (ES), multifidus(MF) and psoas(PS) of subjects with normal bone density were all significantly less than those of subjects with osteopenia and those with osteoporosis. There is an inverse correlation between paraspinal muscle FF and vertebral BMD after controlling for age, sex and BMI. Our results show paraspinal muscle FI increases while vertebral BMD decreases. 

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Quantitative evaluation and correlation analysis withperiacetabular muscle MRI in children with Slipped Capital Femoral Epiphysis (SCFE)
Yue Gao1, Xiao hong Lv2, Qi Li3, Jiazheng Wang4,5, and Shinong Pan1

1Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China, 2Department of Radiology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, China, 3Department of Radiology, Liaoning Electric Power Center Hospital, Shenyang, China, 4Philips Healthcare, Beijing, China, 5Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom

This work compared theperiacetabular skeletal muscle between the healthy and the affected sides for the slipped capital femoral epiphysis (SCFE) patients using MRI. The correlation was studied between the disease progression and the muscle atrophy or fat infiltration to provide a potential criteria in MR images for the

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Permanent and non-permanent changes of skeletal muscle diffusion properties in triathletes and non-athletes detected by diffusion tensor imaging and T2 mapping
Sarah Keller1,2, Enver Tahir2, Jitka Starekova2, Gunnar Lund2, Zhiyue J. Wang3,4, and Jin Yamamura2

1Radiology, Charité University Medicine, Berlin, Germany, 2Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany, 3Radiology, UT Southwestern Medical Center, Dallas, TX, United States, 4Radiology, Children's Medical Center, Dallas, TX, United States

The combined application of MRI Diffusion tensor imaging (DTI) and T2 mapping in professional triathletes and healthy controls at rest and hours after triathlon enables the detection of changes induced in skeletal muscle diffusion properties, and thus microstructure, caused by daily professional training and intensive exercise.

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A preliminary study on the correlation between fat infiltration and muscle asymmetry in lumbar intervertebral disc herniation by using IDEAL-IQ
Hui Hao1, Jiayin Tong1, Xiaocheng Wei2, Jianxin Guo1, Xijun Jiao1, Xianghui Zhang1, and Jian Yang1

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

Disc herniation is one of the most common conditions of the lumbar spine.More and more people are suffering from this symptoms.Our study focused on fat infiltration of bilateral lumbar multifidus muscle in patients with lumbar disc herniation. Based on the IDEAI-IQ technology, proton density fat fraction of lumbar multifidus muscle is evaluted. The preliminary results show that the degree of fat infiltration in the lumbar spine protrusion is relatively higher in the herniated side than contralateral side.Our results can reflect the degree of fat infiltration quantitatively, which can be further expanded into the quantitative classification of different populations and different causes.

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Intravoxel Incoherent Motion (IVIM) Perfusion Imaging of the Shoulder Muscles Activated by Tennis Playing: Initial Results
Patrick Bosshard1, Luciano Pescatore2, Sebastian Kozerke1, and Christian Federau1,3

1Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland, 2University of Zürich, Zürich, Switzerland, 3Radiology, University Hospital of Basel, Basel, Switzerland

Playing tennis involves complex simultaneous motion patterns of several muscles of the shoulder. Intravoxel incoherent motion (IVIM) perfusion imaging offers the possibility to map muscle activation by measuring changes in local blood flow. In this preliminary work four healthy right-handed volunteers were examined after tennis exercises using IVIM perfusion imaging. The results indicate a particular use of m. subscapularis and m. pectoralis major during forehand strokes and of the of m. subscapularis during service.

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Changes in strain tensor resulting from atrophy induced by Unilateral Limb Suspension of the calf muscle.
Vadim Malis1, Usha Sinha2, Ryuta Kinugasa3, and Sinha Shantanu4

1Physics, UC San Diego, San Diego, CA, United States, 2Physics, San Diego State University, San Diego, CA, United States, 3Kanagawa University, Yokohama, Japan, 4Radiology, UC San Diego, San Diego, CA, United States

We quantified 3D strain tensor in the principle and muscle fiber basis along with two invariants (volumetric and octahedral shear strain) from multi-slice velocity encoded phase contrast images of the in-vivo human calf muscle under isometric contractions.  Significant decreases in the medial gastrocnemius and soleus contractile strain eigenvalue and in the invariants with suspension may potentially arise from changes in muscle contractility and/or from extracellular remodeling. The significant reduction in shear strain may indicate a decrease in lateral transmission of force that may account for the disproportionate loss of force to loss of mass with atrophy.

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Creatine and phosphocreatine mapping of mouse skeletal muscle by a polynomial and Lorentzian line-shape fitting CEST method
Lin Chen1,2, Peter B. Barker1,2, Robert G. Weiss2,3, Peter C. M. van Zijl1,2, and Jiadi Xu1,2

1F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Kriger Institute, Baltimore, MD, United States, 2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, 3Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, United States

Wild type (WT) mice and Guanidinoacetate N-Methyltransferase deficiency (GAMT-/-) mice that have low Cr and PCr concentrations in muscle were used to assign the Cr and PCr peaks in the skeletal muscle Z-spectrum. A PLOF method was proposed to simultaneously extract and quantify the Cr and PCr CEST signal by assuming two Lorentzian functions for the Cr and PCr peaks and a polynomial function for the background signal. High-resolution PCr and Cr maps of mouse skeletal muscle were obtained by the PLOF CEST method after calibration with in vivo MRS.

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Intramuscular magnesium measured by 31P-MRS is more closely associated with age and muscle function than is serum magnesium
Donnie Cameron1,2, Ailsa Welch2, Fatemeh Adelnia1, Christopher M. Bergeron1, David A. Reiter3, Nicholas A. Brennan1, Kenneth W. Fishbein1, Richard G. Spencer1, and Luigi Ferrucci1

1National Institute on Aging, National Institutes of Health, Baltimore, MD, United States, 2Norwich Medical School, University of East Anglia, Norwich, United Kingdom, 3Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States

We evaluate the relationships between muscle strength and intramuscular magnesium, measured by phosphorus magnetic resonance spectroscopy (31P-MRS), or serum magnesium. We further evaluate the relationships between these measures of magnesium status and age, sex, and muscle strength. Data were collected from participants in the Baltimore Longitudinal Study of Aging, a large cohort of normatively aging subjects encompassing a broad age range. Results showed that intramuscular magnesium was more closely associated with age and muscle function than was serum magnesium and may therefore represent a better clinical measure of magnesium status.

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Spatial heterogeneities of calf muscle perfusion and its implications
Nan Hu1, Xuenchen Wang2, Christopher Conlin3, Xiaowan Li3, Christopher Hanrahan3, Gwenael Layec4, Lei Zhang5, and Vivian S Lee6

1Internal Medicine, University of Utah Huntsman Cancer Institute, Salt Lake City, UT, United States, 2Population Health Sciences, University of Utah, Salt Lake City, UT, United States, 3University of Utah, Salt Lake City, UT, United States, 4University of Massachusetts at Amherst, Amherst, MA, United States, 5Radiology, University of Utah, Salt Lake CIty, UT, United States, 6Health Platform, Verily, Cambridge, MA, United States

For the study groups of young healthy subjects, aged healthy subjects and peripheral artery disease patients, we measured exercise-stimulated perfusion in calf muscles using both T1-weighted DCE MRI. We found that the heterogeneity and texture complexity of calf muscle (specifically, the medial gastrocnemius and soleus muscle groups) perfusion decreased with exercise load among the young healthy subjects, and decreased with age among all healthy subjects.  In addition, the heterogeneity of the calf muscle perfusion is greater among young healthy subjects when compared with peripheral artery disease patients. 


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How to segment muscle images using qNMRI to obtain the highest discriminant power in natural history studies of muscle diseases in adult patients?
Harmen Reyngoudt1,2, Jean-Marc Boisserie1,2, Julien Le Louër1,2, Cedi Koumako1,2, Benjamin Marty1,2, and Pierre G. Carlier1,2

1NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France, 2NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France

Fat fraction (FF), as calculated from water-fat (Dixon) NMR images, is a largely accepted, if not fully validated, muscle imaging biomarker, which has been proposed as an outcome measure in most neuromuscular disorders these last few years. The question remains, however, as to whether specific muscle or muscle groups should be taken into consideration for longitudinal evaluation in specific neuromuscular diseases. Here, we looked into a cohort of patients suffering from three different neuromuscular disorders: immune-mediated necrotizing myopathy, (sporadic) inclusion body myositis and GNE myopathy. The aim of this work was to compare whole-segment FF with individual muscle and muscle group FF values and identify the most efficient procedure to quantify disease progression, by comparing the standardized response means.

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T2, MTR, and diffusion tensor quantitative MRI methods reliably monitor AAV-mediated gene therapy treatment in a murine muscular dystrophy model
Yasser Nazari1, Joshua Park1, Guy Odom2, Ravneet Vohra1, Jeff Chamberlain2, and Donghoon Lee1

1Department of Radiology, University of Washington, Seattle, WA, United States, 2Department of Neurology, University of Washington, Seattle, WA, United States

Herein we investigate the capability of multi-parametric MRI to reliably and decisively monitor both minute qualitative and quantitative changes in the skeletal muscle microenvironment in a Duchenne muscular dystrophy mouse model, namely mdx4Cv. Through the use of an assortment of pulse sequences, including T2, magnetization transfer ratio, and diffusion tensor imaging, the progression of a recombinant adeno-associated viral vector treatment, by the delivery of a truncated micro-dystrophin gene, is monitored in these mice and better understood. This study fundamentally seeks to understand and confirm the practicality of MRI as a diagnostic and prognostic measure in muscular dystrophy models.

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Longitudinal evaluation of myofiber microstructural changes in an ALS model using MR Cytography
Laura C. Bell1, Alberto E. Fuentes1, Deborah R. Healey1, Natenael B. Semmineh1, Ashley M. Stokes1, and C. Chad Quarles1

1Barrow Neurological Institute, Phoenix, AZ, United States

Amyotrophic lateral sclerosis (ALS) is a fatal upper and lower motor neuron degradation disease that leads to progressive myofiber abnormalities (e.g. decreased size and distribution). With recently FDA-cleared treatments, it is critical to identify non-invasive biomarkers of early disease onset, progression and therapy response. In this study, we validate the potential of a recently developed MR Cytography approach to detect myofiber microstructural changes in an ALS mouse model over three time points by comparison to relevant histologic markers. 

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MRI Differentiation of Morel-Lavallee Lesions from Prepatellar Bursitis
Stephen Broski1 and Justin Friske1

1Radiology, Mayo Clinic, Rochester, MN, United States

Differentiation of prepatellar bursitis from post-traumatic degloving injuries (Morel-Lavallee lesions) about the knee can occasionally present a diagnostic dilemma for clinicians and radiologists, although several features have been described as suggestive of a MLL etiology. 

 

Our study adds to the evidence suggesting that intralesional fat globules and fluid extension beyond the confines of the normal prepatellar bursa are common findings in MLL lesions about the knee and suggestive that a lesion is unlikely to be an isolated prepatellar bursitis.


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A 1x1x1mm isotropic resolution CUBE-FLEX for imaging piriformis syndrome
Daehyun Yoon1, Brian Hargreaves1, Christopher Beaulieu1, and Amelie Lutz1

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

Piriformis syndrome is one of the more common causes for sciatica-type symptoms, defined as impingement of the sciatic nerve by the piriformis muscle. MRI can be very useful in identifying the causative anatomic configuration for presurgical planning, but the conventional 2D sequences can be very challenging for the evaluation of the complex oblique anatomy of the piriformis muscle and sciatic nerve. We present a 5-minute isotropic resolution (1mm3) 3D fast-spin-echo sequence with fat-water separation, allowing arbitrary reformats to specify the causative anatomy as well as T2-weighted contrast to detect abnormal signal of the nerve in the context of associated neuropathy.

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High resolution assessment of intramuscular fat content in the calf using T2-weighted MRI
Xiaowan Li1, Conlin C Christopher1, Christopher Hanrahan1, Vivian S Lee2, and Jeff Lei Zhang1

1Department of Radiology and Imaging Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States, 2Verily Life Sciences, Cambridge, MA, United States

Intramuscular fat is an important indicator of the health of the lower extremities. It can be difficult with conventional Dixon techniques to acquire high resolution fat-fraction maps, which may be helpful for detailed analysis of the muscle tissue. We propose to use a linear model to generate a high resolution fat-fraction map from high resolution T2-weighted images. The results show that the proposed method and the conventional Dixon method have good agreement. The high resolution fat fraction maps generated with the proposed method reveal anatomic details of intramuscular fat not visible with the conventional method.

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Magnetic resonance (MR) imaging-based fat signal fraction quantification of paraspinal back muscle: Comparison of T1, T2 and gradient-echo m-Dixon method
Seong Jong Yun1, Wook Jin1, and Na-Young Choi1

1Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Korea, Republic of

To compare the T1 and T2 m-dixon sequences with GRE mdixon sequence in FF quantification of paraspinal muscles and to evaluate the association of all sequences in FF quantification. Fat fraction quantification of the paraspinal muscles on three m-Dixon MR sequences were different from one another. But, they have the same tendency and strong correlation.

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A quantitative and clinical evaluation of nerve root in lumbosacral radiculopathy using diffusion tensor imaging
Yin Shi1, Weiqiang Dou2, and Haibin Shi1

1The First Affiliated Hospital With Nanjing Medical University, NanJing, China, 2GE Healthcare, MR Research China, Beijing, China

In this study, we aimed to investigate if diffusion tensor imaging technique can quantitatively evaluate nerve root in lumbosacral radiculopathy by measuring MR fractional anisotropy (FA) values. By measuring 34 patients with unilateral disc related lumbosacral nerve root compression, we found that the mean FA value of nerve root correlate significantly with JOA score that is performed on the clinical function of the patients. Therefore, we can demonstrate that DTI can quantitatively and clinically evaluate nerve root by measuring FA values in disc related lumbosacral radiculopathy.

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Evaluation of the risk of osteoporosis in diabetic patients by IDEAL-IQ
Yu Song1, Qingwei Song1, Nan Zhang1, Yanwei Miao1, Ailian Liu1, and Lizhi Xie2

1Department of Radiology, the First Affiliated Hospital of Dalian Medical University, Dalian Liaoning, China, 2GE Healthcare, Beijing, China

Osteoporosis is characterized by "decreased bone strength and increased risk of fracture”. Osteoporosis caused by diabetes is metabolized caused by decreased bone mass, bone microstructural destruction, increased bone fragility and prone to fracture. It is found that IDEAL-IQ can monitor bone marrow fat changes, diagnose bone marrow lesions or evaluate their functional status.

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Evaluation of local changes in femoral bone marrow during a mountain ultra-marathon with quantitative MRI
Hoai-Thu Nguyen1, Thomas Grenier2, Benjamin Leporq2, Loïc Bey1,3, Magalie Viallon 1,3, and Pierre Croisille1,3

1Univ Lyon, UJM-Saint-Etienne, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, Inserm, CREATIS UMR 5220, U1206, F-42023, Saint-Etienne, France, 2Univ Lyon, INSA‐Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F-69621, Villeurbanne, France, 3Department of Radiology, Centre Hospitalier Universitaire de Saint-Etienne, Université Jean-Monnet, Saint-Etienne, France

This study investigates the local changes in femoral bone marrow in a longitudinal MRI dataset of mountain ultra-marathon runners acquired during the Tor des Géants 2014 based on the MRI quantitative metrics with a rigorous statistical analysis procedure. The results highlight the different characteristics of different quantitative metrics that provides multiple insights into the data and open various perspectives for further analysis.

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MR evaluation of hips following surgical reduction for developmental hip dysplasia: Are there quantitative and qualitative predictors of avascular necrosis?
Christian Barrera1 and Jie C Nguyen2

1Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, United States, 2Radiology, Children's Hospital of Philadelphia, philadelphia, PA, United States

The purpose of our study is to investigate whether there are qualitative and quantitative imaging markers on the post reduction MR study that can predict the development of AVN using follow-up pelvic radiographs as reference standards.  Post-reduction contrast-enhanced MR studies from thirty-seven infants with unilateral DDH were retrospectively reviewed which showed focally (27%) or globally decreased femoral head enhancement (22%).  None of the clinical and imaging markers, including both qualitative and quantitative imaging factors present on the post reduction contrast-enhanced MR, can predict the future development of AVN, which sheds light on our incomplete understanding of the underlying pathophysiology.  



Bone 2 & MSK Tumors

Exhibition Hall
Monday 8:15 - 9:15
 Musculoskeletal

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Quantitative comparison of conventional and synthetic MRI for cortical and trabecular bone architecture: ex vivo study of bovine coccyx
Miyuki Takasu1, Yuji Akiyama2, Akira Nishikori2, Yoko Kaichi1, Shogo Maeda1, and Kazuo Awai1

1Department of Diagnostic Radiology, Hiroshima University Hospital, Hiroshima, Japan, 2Department of Radiology, Hiroshima University Hospital, Hiroshima, Japan

Synthetic MRI has recently been shown to offer comparable performance to conventional pulse sequences in the assessment of intracranial abnormalities with greater time efficiency. We assessed the capability to predict bone architecture from MRI by comparing T1 and T2 relaxation times calculated by conventional and synthetic MRI and bone indices determined by micro-CT using bovine coccyx. This experimental study demonstrated that cortical porosity was significantly correlated with the cortical bone T2 relaxation time calculated from synthetic MRI. Synthetic MRI is feasible for assessing bone architecture and bone quality in clinically relevant acquisition time without radiation exposure.

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A fully automatic and robust system for quantitative measurement of lumbar curvature
Yao Wang1, Fei Gao2, Mei Yang1, Shui Liu3, Xiaodong Zhang3, Jue Zhang1,2, and Xiaoying Wang1,3

1Academy for Advanced Interdisciplinary Studies, Peking University, beijing, China, 2College of Engineering, Peking University, beijing, China, 3Department of Radiology, Peking University First Hospital, beijing, China

The change of lumbar curvature is used as the intuitionistic reflection for nearly all lumbar spine lesions, such as low back pain. Although several automatic segmentation methods have been proposed for the lumbar spine, those techniques cannot be directly applied to the diagnosis of spinal lesions due to the lack of quantitative estimation in lumbar curvature. In this study, by using a machine learning strategy, we designed an analysis pipeline and developed a fully automated measurement system of lumbar curvature, then validated it against a dataset of 45 subjects with T2w images.

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Intravoxel Incoherent Motion Outperforms Monoexponential and Kurtosis Models of Diffusion Attenuation in Normal and Inflamed Bone Marrow
Timothy JP Bray1, Alan Bainbridge2, Margaret A Hall-Craggs1, and Hui Zhang3

1Centre for Medical Imaging, University College London, London, United Kingdom, 2Magnetic Resonance Imaging Physics, University College London Hospitals, London, United Kingdom, 3Centre for Medical Image Computing, University College London, London, United Kingdom

Recently, there has been interest in the use of diffusion-weighted imaging (DWI) for quantifying inflammation of the skeleton. In spondyloarthritis, inflammatory exudates in the bone marrow increase the apparent diffusion coefficient (ADC), likely reflecting increased extracellular water. However, the ADC is a simplistic ‘summary’ measure and fails to disentangle the complex pathophysiological changes occurring at inflamed sites. Here, we show that the intravoxel incoherent motion (IVIM) model captures both the rapid ‘perfusion’ component and the slower ‘tissue’ components of the bone marrow diffusion signal, and thus provides a more accurate description of the signal than monoexponential and kurtosis models.

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Percentage fat fraction in magnetic resonance imaging: an upgrade of the osteoporosis detecting parameter
Rong Chang1, Xiaowen Ma1, and Ming Zhang2

1Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an,Shaanxi, China, 2First Affiliated Hospital, Medical College Xi'an Jiaotong University, Xi'an, Shaanxi, China

   The diagnosis of osteoporosis (OP) is mainly based on orthopedic imaging approaches. The percentage fat fraction (FF%) in magnetic resonance imaging (MRI) has the potential to be used to predict and diagnose OP. In both 1-H MRS and mDIXON Quant MRI, the FF% exhibited a negative correlation with BMD. Among the three groups, the OP patients had significantly higher FF% compared to healthy subjects. In addition, the FF% according to mDIXON exhibited a positive correlation with age, and BMD showed a negative linear relationship with age. Furthermore, females had a higher FF% level compared to males. Furthermore, height was correlated with BMD but not FF%. MRI investigation (especially the FF% according to the mDIXON Quant imaging system) is useful in OP assessment. Parameters including gender and age, as well as height, are important factors for OP prediction and diagnosis.

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Evaluation of the Condylar Position and Volume in the Temporomandibular Joint Using Zero Echo Time MRI
Wei-Yin Liu1, Hung-Ta Wu2, Chien-Yuan Eddy Lin3, Hsiao-Ling Lee3, and Wan-You Guo2

1Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan, 2Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan, 3GE Healthcare, Taipei, Taiwan

The first clinical application with zero echo time (ZTE) based MR bone depiction and segmentation in the temporomandibular joint (TMJ) was presented in this study. Our result revealed that ZTE showed computed tomography (CT)-like bone contrast and more detailed demonstration of bony structures, which contributed more reliable structure images and volume measurements. A potential alternative radiation-free diagnostic approach, especially for patients who receive initial workups or serial follow-ups, can be adopted to assess the staging of temporomandibular disorder (TMD) by segmenting cortical bone of the condyle into normal bone, erosion, and sclerosis. 

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Construction of a population-based anatomical knee atlas and a probabilistic map of the spatial BML distribution
Christoph Arthofer1,2,3, Yasmine Zedan1,2,3, Brigitte Scammell1,3,4, Thomas Kurien1,3,4, David Walsh1,3,4, Robert Kerslake1,2,3, and Dorothee Auer1,2,3

1National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham, United Kingdom, 2Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 3Arthritis Research UK Pain Centre and NIHR Nottingham BRC, University of Nottingham, Nottingham, United Kingdom, 4Division of Rheumatology, Orthopaedics and Dermatology, University of Nottingham, Nottingham, United Kingdom

The distribution of bone marrow lesions (BMLs) is an important factor in the assessment of osteoarthritis (OA) in the knee. We present a population-based (PB) anatomical atlas of the knee and a probabilistic map of the spatial distribution of BMLs.

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Evaluation of the Activity of Ankylosing Spondylitis by Diffusion Kurtosis Imaging in Sacroiliitis
zhengyang zhou1, Jian He1, and Weibo Chen2

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

Forty-four patients with AS underwent MRI including DKI to evaluate the disease activity of AS. Four disease activity states were chosen: inactive disease and moderate, high, and very high disease activity. The D and ADC values of sacroiliac joints in the active group were significantly higher, while the K value was significantly lower than those of the inactive group. The D value performed best in distinguishing different activity grades. The D and ADC values correlated positively, while the K value correlated negatively, with activity grade significantly. DKI of sacroiliac joints might be useful to evaluate the disease activity of AS.

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Cardiovascular Risk Factors for degenerative disc diseases of the thoracolumbar Spine in a Healthy General Population: Results from the KORA MRI Study
Sven Stephan Walter1, Elke Wintermeyer2, Roberto Lorbeer3, Sergios Gatidis4, Konstantin Nikolaou1, Fabian Bamberg5, and Mike Notohamiprodjo1

1Department for Diagnostic and Interventional Radiology, University Hospital Tuebingen, Tuebingen, Germany, 2Department for Trauma and Reconstructive Surgery, BG Trauma Center Tuebingen, Tuebingen, Germany, 3University Hospital Munich, Munich, Germany, 4Department for Diagnostic and Interventional Radiology, Univeristy Hospital Tuebingen, Tuebingen, Germany, 5Radiology, University Hospital Freiburg, Freiburg, Germany

Evidence has grown that disc degeneration may be influenced by cardiovascular risk factors. Thus, the purpose was to assess the association in a healthy sample from the general population. Disc degeneration as well as disc bulging and protrusion of the thoracic and lumbar spine was assessed using the Pfirrmann-score and correlated to risk factors such as obesity, hypertension and diabetes. Hypertension dependently while age and BMI independently associated with disc degeneration. Diabetes increased disc degeneration at Th7/8 and L3/4. Lifestyle conditions had no influence. In conclusion, certain cardiovascular risk factors are associated to disc degeneration and disc bulging and protrusion.

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Assessment of the influence of metabolic syndrome on hip osteoarthritis by magnetic resonance imaging in subjects from the general population.
Sven Stephan Walter1, Elke Wintermeyer2, Roberto Lorbeer3, Sergios Gatidis4, Konstantin Nikolaou1, Fabian Bamberg5, and Mike Notohamiprodjo1

1Department for Diagnostic and Interventional Radiology, University Hospital Tuebingen, Tuebingen, Germany, 2Department for Trauma and Reconstructive Surgery, BG Trauma Center Tuebingen, Tuebingen, Germany, 3University Hospital Munich, Munich, Germany, 4Department for Diagnostic and Interventional Radiology, Univeristy Hospital Tuebingen, Tuebingen, Germany, 5Radiology, University Hospital Freiburg, Freiburg, Germany

With being two of the leading chronic diseases, the purpose was to evaluate the effect of the metabolic syndrome on osteoarthritis of the hip in a healthy sample from the general population. Osteoarthritis was assessed according to the Kellgren-Lawrence classification, while the components of the metabolic syndrome were obtained as part of the clinical study protocol. Blood glucose was found to be a borderline non-dependent factor, while there was no correlation for waist circumference, triglyceride, blood pressure, and HDL. The overall metabolic syndrome was also not significantly correlated. In conclusion, metabolic syndrome and osteoarthritis of the hip are not associated.

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Bone marrow adipose tissue with 3T CSE-MRI in vivo:  Preliminary study for long-term repeatibility assessment
Dimitri MARTEL1, Benjamin LEPORQ2, Ravinder R. REGATTE1, Stephen HONIG3, and Gregory CHANG1

1Radiology, NYU LANGONE HEALTH, New York City, NY, United States, 2Université de Lyon; CREATIS CNRS UMR 5220, Inserm U1206, INSA-Lyon, UCBL Lyon 1, Villeurbanne, France, 3Osteoporosis Center, Hospital for Joint Diseases, NYU LANGONE HEALTH, New York City, NY, United States

Bone is composed of two tissues: a mineralized cortical and trabecular bone component and a fatty and hematopoietic marrow component. Osteoporosis is a disease of weak bone and increased fracture risk due to low bone mass. Recent studies pointed link between bone marrow adipose tissue (bMAT) and osteoporosis notably in term of bMAT composition. Chemical Shift- Encoded MRI (CSE-MRI) allows detection of fat amount and fat composition. Our aim was to assess long term repeatability of CSE-MRI in proximal femur bMAT.

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T2* quantification of the cranial bone using ultra-short echo-time (UTE) imaging
Benedikt Herzau1, Martin Krämer1, and Jürgen R Reichenbach1,2,3,4

1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, 2Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, Germany, 3Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany, 4Center of Medical Optics and Photonics, Friedrich Schiller University Jena, Jena, Germany

Quantification of T2* of the human cranial bone was performed by using high resolution multi-echo ultra-short echo time (UTE) imaging. Due to the extracted different short T2* values across the skull, it became possible to identify and differentiate the three-layer structure of the cranial bone consisting of the two compact bone layers lamina externa and lamina interna as well as the spongy interlayer diploe. Significant differences between the spongy interlayer and the two compact layers were obtained as regards their respective T2* relaxation times.

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Bone Fraction Mapping with SyNthetic Auto-interpolated in-Phase (SNAP) MRI
Naomi Sakai1, Timothy Bray1, Stuart Taylor1, Margaret Hall-Craggs1, and Alan Bainbridge2

1UCL Centre for Medical Imaging, University College London, London, United Kingdom, 2Department of Medical Physics, University College London Hospitals, London, United Kingdom

Quantification of bone mineral density (BMD) and/or bone fraction (BF) has long been a goal of MRI research, but thus far no method has successfully translated into clinical practice. Methods including R2* mapping, susceptibility mapping and ultrashort echo time MRI have shown promise but remain difficult to implement. A simpler approach to BMD/BF quantification is to measure the signal loss occurring in bone-containing voxels compared to the signal occurring in a bone-free voxel. We propose a method called SyNthetic Auto-interpolated in-Phase (SNAP) imaging which uses this principle and accounts for spatial variations in B1/coil sensitivity, enabling practical estimation of BMD/BF.

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Impact of Hardware Timing Errors on Quantification of Bone Water with UTE and ZTE
Xia Zhao1, Hyunyeol Lee1, Hee Kwon Song1, and Felix W. Wehrli1

1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States

Radial MR sequences are sensitive to system timing errors, particularly for ultra-short echo time (UTE) and zero echo time (ZTE) techniques. The effects of these timing errors on image quality were systematically evaluated with both simulation and imaging experiments, and their impact on bone water quantification investigated in vivo. Error in bone water concentration in the mid-tibia was found to be up to 35.4% using UTE and 16.6% for ZTE in the presence of timing errors as small as 6 μs. Further, the severity of image artifacts were spatially dependent, with objects further from FOV center more highly distorted.

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Differentiation of Vertebral Fracture Types using Five Different Convolutional Neural Network Approaches
Lee-Ren Yeh1, Yang Zhang2, Jeon-Hor Chen1,2, Peter Chang2, Daniel Chow2, and Min-Ying Lydia Su2

1Department of Radiology, E-Da Hospital and I-Shou University, Kaohsiung, Taiwan, 2Department of Radiological Sciences, University of California, Irvine, CA, United States

Differentiation of benign from malignant vertebral fracture is challenging yet very important for therapeutic planning. In this study, deep learning was conducted to automatically differentiate the fracture types using 5 different convolutional neural networks, including ResNet50, DenseNet, Xception, xceptionResNetV2, and InceptionV3. The final segmentation model was developed using 10-fold cross-validation applied in two different input methods, i.e. single slice or each slice combined with its two neighboring slices. Overall, the prediction accuracy was improved when each slice combined with its two neighboring slices was used as the input. Among the five deep learning approaches, XceptionResnetV2 showed the highest prediction accuracy.  

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Small-sized soft tissue tumor with deep location: Can MRI be used to differentiate benign from malignancy?
Ji Hyun Lee1, Hyun Su Kim1, Young Cheol Yoon1, Wook Jin2, and Jang Gyu Cha3

1Radiology, Samsung Medical Center, SEOUL, Korea, Republic of, 2Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Korea, Republic of, 3Radiology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea, Republic of

Small deep soft tissue tumors often results in dilemmatic clinical situation and raise clinical concern that deep location is one of risk factor for malignancy. We conducted this study hypothesizing that DWI with ADC value as well as conventional MRI parameters could help differentiation of benignity and malignancy for small deep soft tissue tumors; univariable and multivariable analyses were performed for all tumors and non-myxoid non-hemosiderin tumors. Although only small tumors were enrolled, lesion size was still important for differentiation of benign and malignant soft tissue tumors, being the most significant parameter in non-myxoid non-hemosiderin group.

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Differentiation of Soft Tissue Lymphoma from Undifferentiated Sarcoma: ADC Histogram Analysis of Whole Tumor Volume and Single-Slice ADC Measurements at 3T
Won-Hee Jee1, Sunyoung Whang1, Chan Kwon Jung2, Joon-Yong Jung1, Yohan Son3, Mun Young Paek3, Yang-Guk Chung4, and Seok-Goo Cho5

1Radiology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea, Republic of, 2Pathology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea, Republic of, 3Siemens Healthineers, Seoul, Korea, Republic of, 4Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea, Republic of, 5Hematology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea, Republic of

Diffusion-weighted MR imaging should be included in differentiating soft tissue lymphoma from undifferentiated sarcoma to avoid unnecessary surgery in soft tissue lymphoma.

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Clinical-Radiomics Nomograms for Preoperative Differentiation of Sacral Chordoma and Sacral Giant Cell Tumor Based on 3D Computed Tomography and Multiparametric Magnetic Resonance Imaging
Ping Yin1, Sicong Wang2, and Nan Hong1

1Department of Radiology, Peking University People's Hospital, Beijing, China, 2Pharmaceutical Diagnostic team, GE Healthcare, Life Sciences, Beijing, China

The purpose of our study was to build and evaluate clinical-radiomics nomograms for the preoperative differentiation of SC and SGCT. We compared individual features and mixed features based on CT and MRI respectively. And we also added clinical data to compare these models in terms of their performance of distinguishing SC and SGCT. Our results reveal that the model based on DWI features had the highest performance among individual scans. Mixed CT features performed better than individual scan, while mixed MR features achieved a low performance. Radiomics model can perform better when combined with clinical data.

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Whole body MRI in myeloma: Optimising scan acquisition and read times.
Saurabh Singh1, Elly Pilavachi1, Alexandra Dudek1, Timonthy JP Bray1, Arash Latifoltojar1, Kannan Rajesparan1, Shonit Punwani1, and Margaret Hall-Craggs1

1Centre of Medical Imaging, University College London, London, United Kingdom

The study aim was to identify the highest value sequences for assessment of multiple myeloma by whole body MRI (WBMRI) to optimize scan acquisition and read times. Individual sequences (Dixon -/+ contrast, and diffusion imaging) were assessed in a prospective cohort of 29 patients with newly diagnosed multiple myeloma. Scan sensitivity, positive predictive value and reader confidence in detecting myeloma lesions and lesion conspicuity were assessed. Post-contrast water only Dixon and diffusion weighted images performed best. The results suggest that scan acquisition and read time can be reduced by focussing on WO contrast enhanced and diffusion images.  

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Diffusional kurtosis imaging in the differentiation of benign and malignant bone tumors
Ying Li1, Cuiping Ren1, Jingliang Cheng1, and Zhizheng Zhuo2

1First affiliated hospital of Zhengzhou university, Zhengzhou, China, 2Clinical Science, Philips Healthcare, Beijing, China

This work investigated and evaluated the role of magnetic resonance (MR) diffusion kurtosis imaging(DKI) in characterizing the bone tumors, and furtherly evaluate the ability of DKI parameters to differentiate benign and malignant tumors by using receiver operating characteristic curve(ROC), which might be helpful for clinical diagnosis and studies.

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Feasibility study of intra-voxel incoherent motion MR imaging for the differentiation of benign and malignant bone tumors
Ying Li1, Cuiping Ren1, Jingliang Cheng1, and Zhizheng Zhuo2

1First affiliated hospital of Zhengzhou university, Zhengzhou, China, 2Clinical Science, Philips Healthcare, Beijing, China

This work investigated and evaluated the role of intra-voxel incoherent motion(IVIM) MR imaging in characterizing the bone tumors, which might be helpful for clinical diagnosis and studies.

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Exploratory evaluation of magnetic resonance fingerprinting confirms increased T1 and T2 in metastatic breast and prostate cancer lesions compared with normal marrow and volunteer values
Matthew R Orton1, Mihaela Rata1,2, Nina Tunariu1,2, Julie Hughes2, Erica Scurr2, James A d'Arcy1, Martin O Leach1, Wei-Ching Lo3, Mark Griswold3,4, Yun Jiang3, Vikas Gulani3,4, and Dow-Mu Koh1,2

1CRUK Cancer Imaging Centre, Division of Radiotherapy and Imaging, Institute of Cancer Research, London, United Kingdom, 2Department of Radiology, Royal Marsden NHS Foundation Trust, London, United Kingdom, 3Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 4Department of Radiology, Case Western Reserve University, Cleveland, OH, United States

Magnetic resonance fingerprinting (MRF) is a rapid imaging technique that allows generation of multiple, co-registered quantitative maps from a single sequence. This technique has been evaluated in the brain, abdomen, prostate, breast and heart, but has not been applied to metastatic disease in the skeleton.  This abstract documents T1 and T2 values obtained with MRF in metastatic bone disease, muscle, fat and bone marrow, compares them with values obtained in volunteers using gold-standard imaging and MRF and demonstrates increased T1 and T2 in lesions compared with normal marrow and values in volunteers.

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Diagnostic value of MR imaging with metal artifact reduction sequences in local recurrence of malignant bone tumor after joint replacement
Hanqi Wang1 and Yong Lu1

1Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China

Effective imaging evaluation after joint replacement is important for patients with malignant bone tumor. This study investigated the diagnostic value of MR imaging with metal artifact reduction sequences (MARS) in local recurrence of malignant bone tumor after joint replacement. The sensitivity, specificity, coincidence rate and Kappa value of MARS in the diagnosis of local recurrence were higher than FSE sequences. The ICC was 0.961 between MR images and pathology in measuring recurrent tumor volume. MR imaging with MARS has significant diagnostic value in local recurrence of malignant bone tumor after joint replacement. 

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Usefulness of 3-dimensional MR Texture Analysis (3D-MRTA) for Distinguishing Well-differentiated Liposarcoma fom Lipoma
Seong Jong Yun1, Wook Jin1, Na-Young Choi1, and Kyung Nam Ryu2

1Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Korea, Republic of, 2Department of Radiology, Kyung Hee University Hospital, Seoul, Korea, Republic of

Although magnetic resonance (MR) imaging has been used as standard imaging tool, because of overlapping imaging features, the discrimination between well-differentiated liposarcoma and lipoma is not always clear. Also, no study has evaluated the diagnostic usefulness of 3-dimensional MR texture analysis (3D-MRTA) for distinguishing well-differentiated liposarcoma from lipoma. Therefore, the purpose of this study is to evaluate the usefulness of 3D-MRTA for differentiation between well-differentiated liposarcoma and lipoma, diagnosed on the basis of histopathological features. Regarding mean, MPP, kurtosis, and entropy, values on all sequences were significantly higher in well-differentiated liposarcoma than those in lipoma (p<0.001). The two best performing 3D-MRTA parameters were kurtosis on T2WI (AUC, 0.86; 95 % CI, 0.77-0.95) and entropy on FS-T1CE (AUC, 0.83; 95 % CI, 0.74- 0.93). There were good or excellent interobserver agreements for all measurements (ICC, 0.750–0.885).

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Assessment of Multiple Myeloma pH Using AcidoCEST-FISP MRI at 7T
Rachel High1,2, Adam Searleman2, Yajun Ma2, Qingbo Tang2,3, Jonathan Wong2,3, Jiang Du2, Patrick Frost4, Mark D Pagel5, and Eric Y Chang2,3

1University of Arizona, Tucson, AZ, United States, 2Department of Radiology, University of California San Diego, San Diego, CA, United States, 3Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States, 4Research Service, Greater Los Angeles Veterans Administration Healthcare System, Los Angeles, CA, United States, 5Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, United States

Hypoxic conditions in multiple myeloma (MM) lesions drive anaerobic glycolysis and tumor acidosis, which contributes to tumor aggression and metastasis. In vivo imaging of acidosis in these lesions is important for determining the role of extracellular pH (pHe) in the pathology and spread of MM tumors. In this study, we use a novel imaging technique called chemical exchange saturation transfer (CEST) MRI to measure acidosis in vivo. We show that we are able to measure pH in MM lesions located in both vertebral bodies and regions of the knee using CEST MRI. 

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The parameters of Intravoxel Incoherent Motion Diffusion-Weighted Imaging for evaluating microstructure of bone marrow in myeloproliferative diseases: a Pilot Study
jinliang niu1, wenqi wu1, rong fan1, kaiyu wang2, and weiguo li3

1The second hospital of Shanxi Medical University, taiyuan, China, 2Healthcare,MR Research China, Beijing, China, 3Department of Radiology, Northwestern University, Chicago, American Samoa

Many myeloproliferativediseases,e.g., anemia and acute leukemia, impair microstructure of bone marrow. However, it is unclear the relationship between parameters of IVIM and microstructure of bone marrow (cellullarity, and microvessel density).Texture analysis was performed on D, D* and fmaps of the spinal bone marrow extracted from IVIM MRI on 48 patients (28 patients with acute leukemia and 20 patients with anemia). Bone marrow cellularity and MVD were significantly different between two groups. The f values in group of acute leukemia were significantly higher than that of anemia . The texture parameters of D, D* and f mapping has potential to reveal heterogeneous feature of microstructure in bone marrow.


Cartilage 2, Meniscus, Tendon & Ligament

Exhibition Hall
Monday 8:15 - 9:15
 Musculoskeletal

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Uncompromised MRI of knee cartilage while incorporating sensitive sodium MRI
Sander Brinkhof1, Aidin Ali Haghnejad2, Keita Ito3,4, Karin Markenroth Bloch5, and Dennis Klomp1

1Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2WaveTronica, Utrecht, Netherlands, 3Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 4Orthopaedics, University Medical Center Utrecht, Utrecht, Netherlands, 5BioImaging Center, Lund University, Lund, Sweden

The goal of this work is to implement a dual tuned sodium-proton coil as transceiver for sodium and transmitter for hydrogen with a high-density proton receive array and compare the proton imaging performance with a state-of-the-art single tuned knee coil.  A double-tuned knee coil was constructed as a shielded birdcage and 15 channel proton receiver coil embedded within the double-resonant birdcage. The double-tuned coil was implemented with comparable proton quality and acceleration possibilities compared to the single-tuned alternative while also being able to acquire high SNR sodium images.

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Minimized PET Attenuation in PET-MRI Knee Scanning with Flexible, Screen-Printed MR Coils
Feliks Kogan1, Lauren E Watkins1, Jacob Thoenen1, Peder Larson2, and Garry E Gold1

1Radiology, Stanford University, Stanford, CA, United States, 2Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, United States

Simultaneous PET-MRI imaging is an exciting new technology for quantitative assessment of whole-joint disease in osteoarthritis (OA). Attenuation correction (AC) for MRI hardware is a challenge for PET quantification in hybrid PET-MRI systems. In this work, we tested a new, lightweight, screen-printed, flexible, 12-channel phased-array MR coil which reduces PET photon attenuation from MR hardware in a PET phantom to below 3%, potentially removing the need to correct for it.  Further, the close proximity of coil elements to the knee show promise for high SNR MRI knee imaging.

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Optimized echo-times for biexponential T2-weighted imaging of the knee cartilage
Nima Gilani1

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

T2-weighted MR signal of the cartilage knee has shown to be better explained by the biexponential relaxation model. The short and long T2 signal components presumably describe tightly bound and loosely bound macromolecular water components of the knee, respectively. More precise estimation of these two parameters might help in the better diagnosis of Osteoarthritis in reasonable scanning times. Here, Cramér-Rao Lower Bound method was used to find optimum echo times that improve estimation of these relaxation components. It was shown that using maximum echo times of twice as much as what is routinely used might substantially improve the biexponential estimates. Echo time optimization might play a role as important as increasing acceleration factors in reducing acquisition times. 

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The b-value dependence of apparent diffusion coefficient (ADC) values in the knee cartilage
Daehyun Yoon1, Sanghee Choi2, Bragi Sveinsson3, and Brain Hargreaves1

1Radiology, Stanford University, Stanford, CA, United States, 2Radiology, Sungkyunkwan University, Suwon, Korea, Republic of, 3Radiology, Harvard Medical School, Charlestown, MA, United States

Apparent diffusion coefficient (ADC) can be a useful marker to track the degeneration of the knee cartilage during the early stage of osteoarthritis. We recently observed that the estimated ADC values change depending on the adopted b-values used in a DW-EPI sequence. We tested our hypothesis about this b-value dependence of ADC with in-vivo knee scans of 7 healthy subjects. Our statistical test result shows that the ADC estimated with the smaller b-values (0~150 s/mm2) is significantly higher than the ADC estimated with the larger b-values (0~800 s/mm2), suggesting the possibility of multi-component diffusion in the knee cartilage.  

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The role of contrast-enhanced whole-body joint MRI in juvenile idiopathic arthritis (JIA)
Lu Yutong1 and Tamotsu Kamishima1

1Faculty of Health Sciences, Hokkaido University, Sapporo, Japan

Due to the limitations of clinical description in diagnosis of juvenile idiopathic arthritis(JIA) with subjective factors, this study attempts to explore the role of contrast-enhanced whole-body MRI(WBMRI) in the JIA. We evaluated the WBMRI images of 156 joint regions of 7 patients, including image quality and positive findings, and compared the results with clinical descriptions. The results showed that WBMRI could observe the lesion of joints more objectively and comprehensively than the clinical description, and could show the changes of the lesions with treatment. Therefore, WBMRI may be used to help diagnose JIA and to evaluate the therapeutic effect.

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Quantification of Non-calcified and Calcified Zones in Articular Cartilage using MRI and PLM at Microscopic Resolution
Farid Badar1 and Yang Xia1

1Physics, Oakland University, Rochester Hills, MI, United States

The zone of calcified cartilage is the least explored region of cartilage in MRI, due to a strong dipolar interaction and a high mineralization of the subchondral region in articular cartilage. T2 weighted images by standard SE and GE sequences show little intensity of ZCC, whereas T2 and T1 weighted at the magic angle can highlight some parts of the region. Quantitative UTE can measure T2 of ZCC down to a fraction of a millisecond. With the aid of PLM, we can correlate the quantitative µMRI data with the optical properties of the ZCC. 

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Quantitative Evaluation of the Relationship Between the Femoral Trochlear Dysplasia and the Degeneration of the Patellofemoral Cartilage by MR T2mapping Technique
Siran Chen1, Xinwei Lei1, Yingying An1, Ying Zhan1, Zhizheng Zhuo2, and Jin Qu1

1Department of Radiology, Tianjin First Center Hospital, Tianjin, China, 2Clinical Science, Philips Healthcare, Beijing, China

Femoral trochlear dysplasia (FTD) is one of the common causes of early injury of knee cartilage in young people, and most of patients of FTD with the history of patellar dislocation, which seriously affects the quality of patients’ life. We focus on all the lateral, medial, deep and superficial layers of both patella and femoral trochlear cartilage in young people with quantitative T2 mapping. We find the superficial layers of lateral patellofemoral cartilage is mainly dehydration change in FTD, and there is more range of cartilage biochemical changes in age<30 years, compared to in age≧30 years, because the controls may appear the cartilage degeneration with increased in age. Compared to the type A of FTD, there are more and wider areas of cartilage dehydration in type B-D, and one of them involve the deep layer and show edema.

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UTE T2* cartilage mapping: Regional differences in asymptomatic hips
Tony T Wong1, Patrick Quarterman1, Diego Jaramillo1, Thomas S Lynch2, and Sachin T Jambawalikar1

1Department of Radiology, Columbia University Medical Center, New York, NY, United States, 2Department of Orthopedic Surgery - Center for Shoulder, Elbow, and Sports Medicine, Columbia University Medical Center, New York, NY, United States

UTE T2* images were acquired in 8 asymptomatic hips. The hip cartilage was segmented into anterosuperior, superior, and posterosuperior regions. Differences in mean T2* values between these regions were assessed. Results demonstrated a significant increase in the mean value of the anterosuperior region compared to the posterosuperior region. 

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CAN PREOPERATIVE MR IMAGING FINDINGS PREDICT EARLY FAILURE FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION?
Michele Mastio1, Alejandra Duarte2, Jose Raya3, Laith Jazrawi1, and Jenny T. Bencardino4

1NYU Langone Orthopedic Center, NYU Langone Health, New York, NY, United States, 2NYU Center for Biomedical Imaging, New York, NY, United States, 3Radiology, NYU Center for Biomedical Imaging, New York, NY, United States, 4Radiology, NYU School of Medicine, Great Neck, NY, United States

Despite all the attention given to anterolateral ligament injury as potential outcome predictor in the postoperative ACL knee, we found that MM tears perform best at predicting early ACRL failure. Preserving the integrity of the MM during ACLR procedure may be crucial in minimizing the risk for early ACLR failure.

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Comparison of Radial and Spiral UTE MRI and T2* quantification of the Knee Joint
Jeehun Kim1, Richard Lartey1, Kecheng Liu2, Tiejun Zhao2, Thomas Benkert3, Heiko Meyer3, and Xiaojuan Li1

1Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, Cleveland, OH, United States, 2Siemens Medical Solution Inc, Malvern, PA, United States, 3Siemens Healthcare GmbH, Erlangen, Germany

The ultrashort TE (UTE) sequences allow measurement of fast-decaying signal from short T2* tissues in the joint such as tendon, ligament, and meniscus. By acquiring multiple echoes along the decay, T2* map can be generated, which has a potential to be used as a biomarker for diseases such as arthritis and tendinopathy. However, the comparison of T2* maps from different UTE sequences has not been fully explored. In this study, UTE based on stack of spirals and 3D radial acquisition were compared.

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High-resolution ultra-short echo-time (UTE) ex-vivo imaging of Achilles tendons at 9.4T by water content alteration
Martin Krämer1, Karl-Heinz Herrmann1, Nicholas M Brisson2, Stefan Zachow3, Georg N Duda2, and Jürgen R Reichenbach1,4,5,6

1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, 2Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité – Universitätsmedizin Berlin, Berlin, Germany, 3Zuse Institute Berlin, Berlin, Germany, 4Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, Germany, 5Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany, 6Center of Medical Optics and Photonics, Friedrich Schiller University Jena, Jena, Germany

To enable high-resolution imaging of ex-vivo ovine and porcine Achilles tendons, samples were extracted and stored in distilled water for up to 7 days to induce water intake and prolonged T2. One sample was measured continuously to quantify the change in T2 over time, while the other/second sample was used to acquire high-resolution structural images using a cryogenic measurement coil at 9.4T.

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Time-resolved mapping of T2* in the patellar tendon during active knee flexion using multi-echo ultra-short echo-time (UTE) imaging
Martin Krämer1, Nicholas M Brisson2, Stefan Zachow3, Georg N Duda2, and Jürgen R Reichenbach1,4,5,6

1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, 2Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité – Universitätsmedizin Berlin, Berlin, Germany, 3Zuse Institute Berlin, Berlin, Germany, 4Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, Germany, 5Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany, 6Center of Medical Optics and Photonics, Friedrich Schiller University Jena, Jena, Germany

To investigate the distribution of T2* in the patellar tendon, and its dependency on factors such as tendon rotation angle and tendon composition, real-time ultra-short echo-time (UTE) imaging was performed during active knee flexion. While T2* is known to depend on the magic angle, it may also be influenced by the underlying tendon structure, which changes its composition when approaching the entheses.

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T1 and T2* relaxation parameter mapping of the patellar and quadriceps tendon by using ultra-short echo-time (UTE) imaging at 3T
Marta Brigid Maggioni1, Martin Krämer1, and Jürgen R. Reichenbach1,2,3,4

1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich Schiller University, Jena, Germany, 2Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University, Jena, Germany, 3Abbe School of Photonics, Friedrich Schiller University, Jena, Germany, 4Center of Medical Optics and Photonics, Friedrich Schiller University, Jena, Germany

The tendon tissues in the knee are characterized by a short T2 relaxation time due to their fibrous structure and their high collagen content. Conventional MRI technique are unable to pick up such fast decaying signal, thus new methods and sequences such as UTE have been introduced. In this work a 3D UTE sequences was applied to quantify the T2* and T1 relaxation parameters for the patellar and quadriceps tendons.

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Improving the Conspicuity of Meniscal Tears in Knee MRI at 3T and 7T
Venkata Veerendranadh Chebrolu1, Peter Kollasch1, Benjamin Howe2, Matthew Frick2, Suzanne L Carlson2, Daniel B Spence2, and Kimberly K Amrami2

1Siemens Healthineers, Rochester, MN, United States, 2Department of Radiology, Mayo Clinic, Rochester, MN, United States

In this work we propose the application of a small percentage of fat-saturation (fat-sat) using Spectral Heterogeneity Adaptive RF Pulses (SHARP) to improve the conspicuity of meniscal tears at 3T and 7T. Knee Turbo-spin-echo (TSE) MRI without fat-sat was compared with TSE MRI with a small percentage of fat-sat applied using SHARP to demonstrate the improvement in conspicuity of meniscal tears with SHARP at 3T and 7T.

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Three-Dimensional Ultrashort Echo Time(3D UTE) MRI of Achilles Tendon at 4.7TMRI With Comparison to ConventionalSequences in an Experimental MurineModel of Spondyloarthropathy
benjamin dallaudiere1, aurelien trotier1, emeline ribot1, sebastien lepreux1, sylvain miraux1, and olivier hauger1

1CNRS, UMR 5536, Université de Bordeaux, bordeaux, France

Unlike bSSFP T2 sequences, 3D-UTE sequences enable visualization of normal enthesis anatomy and early detection of abnormalities in pathological conditions.

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The comparison of two ultra-short echo time methods for T2* mapping in Achilles tendon and enthesis
Vladimir Juras1,2, Peter Latta3, Martin Kojan3, Zenon Starcuk4, Xeni Deligianni5, Oliver Bieri5, and Siegfried Trattnig1

1High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria, 2Institute of Measurement Science, Slovak Academy of Sciences, Bratislava 4, Slovakia, 3Central European Institute of Technology, Masaryk University, Brno, Czech Republic, 4Institute of Scientific Instruments, Czech Academy of Sciences, Brno, Czech Republic, 5Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland

We compared the performance of two MR techniques, ultra-short TE (UTE) and variable-echo time (vTE), to estimate mono- and bi-exponential T2* in Achilles tendon and enthesis at 3T. In axial slice orientation, the mean T2* values for UTE were (mono, short, long) 4.1 ± 1.1 ms, 0.9 ± 0.3 ms and 19.6 ± 7 ms, for vTE we found the values 10.5 ± 3.9 ms, 1.4 ± 0.4 ms and 25 ± 3 ms. In sagittal slice orientation, the mean T2* values for UTE were (mono, short, long) 2.8 ± 0.5 ms, 0.4 ± 0.1 ms and 10.5 ± 1.7 ms, for vTE we found the values 5.3 ± 1.5 ms, 1.6 ± 0.3 ms and 22.3 ± 5.6 ms. T2* values calculated with vTE are overestimated in comparison to UTE, however, the clinical value of vTE might be higher, since it provides more slices with reduced blurring and lower scan times.

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Utility of radial reformatted images created from 3T high-resolution 3D wrist MRI in evaluation of the radioulnar ligaments.
Taiki Nozaki1, Saya Horiuchi1,2,3, Akimoto Nimura3,4, Atsushi Tasaki5, Nobuto Kitamura5, Keiichi Akita3, Yasuyuki Kurihara1, and Hiroshi Yoshioka2

1Department of Radiology, St.Luke's International Hospital, Tokyo, Japan, 2Department of Radiological Sciences, University of California, Irvine, Irvine, CA, United States, 3Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan, 4Department of Functional Joint Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan, 5Department of Orthopaedic Surgery, St.Luke's International Hospital, Toyo, Japan

The radioulnar ligament (RUL) has been thought as the major stabilizer of the distal radioulnar joint (DRUJ) under dynamic loading. A detailed depiction of the dorsal and palmar RULs on MRI is very important. However, identification of the RULs including their ulnar styloid attachment on MRI is very difficult on the routine coronal plane, due to not only their small size with complexity of structures but the partial volume effect. The purpose of this study was to investigate the value of radial-slice MPR images sourced from 3D isotropic high-resolution MR images for the depiction of the RULs.

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The value of 30°flexed knee MRI in evaluating anterior cruciate ligament tears
Xiao Jin1, Yakui Wang1, Qiang Zhao1, Ning Lang1, and Huishu Yuan1

1Radiology, Peking University Third Hospital, Beijing, China

The study aimed to investigate the value of 30°flexed knee MRI in evaluating anterior cruciate ligament (ACL) tears. 64 patients with knee trauma and hospitalized for arthroscopy were included and performed knee MRI in slightly flexed(about 17°) and 30° flexed positions successively. Images of both positions have high sensitivity, specificity and accuracy in diagnosing ACL tears.30°flexion images were superior to 17°in delineating ACL full length, torn ACL’s disrupted sites and ligament remnants, while no significant difference was found in delineating ACL double-bundle structure. Thus 30°flexed knee MRI was recommended in patients suspecting ACL tears.

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Could the 3D CAIPIRINHA accelerated SPACE imaging replace the conventional 2D MRI in routine knee examination?
Ruyi Xie1, Dong Sun1, Xiaoyue Zhou2, Qiong Zhang3, and Xiaoming Li1

1Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wu Han, China, 2Siemens Healthcare Ltd., Shanghai, China, Shanghai, China, 3Siemens Healthcare Ltd.,Shenzhen, China, Shen Zhen, China

3D CAIPIRINHA accelerated SPACE is a newly developed technic that can achieve faster acquisition and high resolution isotropic 3D imaging of the knee. However, its clinical diagnostic performance in knee joint hasn’t been proved yet. In this study, we compared the clinical diagnostic performance of 3D CAIPIRINHA accelerated SPACE and the conventional routine knee MRI in patients with knee injuries. We found that 3D CAIPIRINHA accelerated SPACE was able to detect more cartilage lesions and meniscus tear than the conventional 2D knee protocol. Whereas, the clinical diagnostic performance of the other lesions, such as bone marrow edema and ligaments tear were similar of the two protocols.

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Effects of sampling window on quantitative imaging of major tissues in the knee joint using 3D ultrashort echo time (UTE) Cones sequences
Lidi Wan1,2, Yajun Ma1, Saeed Jerban1, Micheal Carl3, Eric Y Chang1,4, Guangyu Tang2, and Jiang Du1

1Department of Radiology, UC San Diego, San Diego, CA, United States, 2Department of Radiology, Shanghai Tenth People's Hospital of Tongji University, Shanghai, China, 3GE healthcare, San Diego, CA, United States, 4Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

We have developed a series of 3D UTE-Cones MRI techniques for quantitative assessment of all major tissues in the knee joint. Continuing improvements in scan time will facilitate their clinical use, but it remains unclear how acceleration affects quantification. This study focused on the effects of stretching sampling windows on quantitative UTE biomarkers in cadaveric human knee joint tissues. We found that extending sampling windows results in vastly reduce scan time without adverse effects on quantitative accuracy of T1, AdiabaticT1ρ, macromolecular fraction and MTR of articular cartilage, menisci, tendons and ligaments in the knee joint.

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Assessing the performance of knee meniscus segmentation with deep convolutional neural networks in 3D ultrashort echo time (UTE) Cones MR imaging
Michal Byra1,2, Mei Wu1, Xiaodong Zhang1, Hyungseok Jang1, Yajun Ma1, Eric Chang1,2, Sameer Shah3, and Jiang Du1

1Department of Radiology, University of California, San Diego, CA, United States, 2Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States, 3Departments of Orthopedic Surgery and Bioengineering, University of California, San Diego, CA, United States

Automatic segmentation of the knee menisci would facilitate quantitative and morphological evaluation in diseases such as osteoarthritis. We propose a deep convolutional neural network for the segmentation of 3D UTE-Cones Adiabatic T1ρ-weighted volumes of the meniscus. To show the usefulness of the proposed method, we developed the models using regions of interests provided by two radiologists. The method produced strong Dice scores and consistent results with respect to meniscus volume measurement. The inter-observer agreement between the models and the radiologists was very similar to that of the radiologists alone.

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Fat suppression based on single point Dixon for morphological and quantitative UTE imaging
Hyungseok Jang1, Yajun Ma1, Michael Carl2, Saeed Jerban1, Eric Y Chang1,3, and Jiang Du1

1Department of Radiology, University of California San Diego, San Diego, CA, United States, 2GE Healthcare, San Diego, CA, United States, 3Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

Use of fat saturation pulses with UTE sequences can improve short T2 contrast and parameter estimation, but can reduce the short T2 signal due to the broad spectrum. Moreover, conventional two-/three-point Dixon-based methods can misestimate fat contents due to the short T2* decay in UTE imaging. In this study, we demonstrate feasibility and efficacy of a single point Dixon method to suppress fat for morphological and quantitative UTE imaging. We evaluate the proposed framework in in vivo experiments in a clinical 3T MR system: morphological UTE imaging and UTE-T1 mapping in knee joints and UTE-bone imaging in a leg. 

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Meniscal Tear Detection with Machine Learning: Initial Experience
Eric M Bultman1, Akshay S Chaudhari1, Arjun D Desai1, and Garry E Gold1

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

Despite rapid recent advances in convolutional neural networks used for image classification, generalizability of these networks to medical image data has not been thoroughly investigated.  In this work, we utilize two networks designed to classify ImageNet natural-image data – Inception-v3 and ResNet-50 – and investigate their performance in classifying meniscal tears on MR examinations of the knee.  Using limited segmentation and manual tear identification, slice-wise sensitivity of 0.68 and 0.58 is achieved for the respective networks.  Applying the “two-slice-touch” rule, sensitivity is significantly increased, but with concomitant decrease in specificity.  Our results support the feasibility of utilizing CNNs for meniscal tear identification.

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Accurate 3D T2 Relaxometry with Simultaneous High-Resolution Structural Imaging using Deep Learning
Akshay S Chaudhari1, Arjun D Desai1, Zhongnan Fang2, Eric M Bultman1, Jin Hyung Lee3, Garry E Gold1, and Brian A Hargreaves1

1Radiology, Stanford University, Palo Alto, CA, United States, 2LVIS Corporation, Palo Alto, CA, United States, 3Neurology, Stanford University, Palo Alto, CA, United States

Rapidly obtaining high-resolution structural magnetic resonance images (MRI) and generating quantitative biomarkers, such as the T2 relaxation time, using a single sequence is useful for musculoskeletal imaging. However, high-resolution is at odds with high signal-to-noise ratio (SNR) in MRI, which makes it challenging to simultaneously optimize for image quality and quantitative accuracy. In this study, we demonstrate how deep-learning-based super-resolution can create high-resolution images with accurate T2 values using a prospectively-sampled 5-minute quantitative double-echo steady-state sequence. We validate this method using high-SNR reference sequences for T2 accuracy and high-resolution reference sequences and a reader study for image quality assessment.

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Prospective Fast T1ρ Mapping of Knee Articular Cartilage using Compressed Sensing
Mingrui Yang1, Jeehun Kim1,2, Chaoyi Zhang3, Leslie Ying3, and Xiaojuan Li1

1Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, Cleveland, OH, United States, 2Electrical Engineering, Case Western Reserve University, Cleveland, OH, United States, 3Electrical Enigeering, University of Buffalo, Buffalo, OH, United States

Quantitative magnetic resonance (MR) mapping is known to provide additional information compared to the conventional qualitative weighted MR images. Relaxation times such as spin-spin relaxation time (T2) and spin-lattice relaxation time (T1ρ) have been shown enable early detection of human knee cartilage degeneration. Obtaining these relaxation parameter maps, however, requires long acquisition time. Compressive sensing (CS) has been extensively studied over the last decade as one of the possible ways to accelerate MR acquisition. These studies, however, are retrospective. In this study, we perform a prospective downsampling study on T1ρ mapping of knee cartilage using CS, which implements the downsampling pattern into the in vivo MR scan sequence.


MSK Techniques & Development: Other MSK

Exhibition Hall
Monday 8:15 - 9:15
 Musculoskeletal

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Clinical shoulder MR imaging at 7 Tesla in comparison to arthroscopy and 1.5 Tesla MRI
Oliver Kraff1, Andrea Lazik-Palm2, Stefan HG Rietsch1,3, Sascha Beck4, Konrad Koersmeier5, Michael Kamminga5, Jens M Theysohn2, and Harald H Quick1,3

1Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany, 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany, 3High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 4Department of Trauma and Orthopedic Surgery, University Hospital Essen, Essen, Germany, 5Facharztklinik Essen, Essen, Germany

An 8-channel transmit/15-channel receive radiofrequency coil setup for 7T shoulder imaging has been evaluated in eight patients presenting with shoulder pain. In total, ten gradient echo and turbo spin echo sequences were included in the imaging protocol. Image quality was assessed in consensus by two radiologists. A structured report focusing on the rotator cuff was generated based on the 7T images and subsequently compared with the arthroscopical report taken as the gold standard. Finally, pathologies found at 7T were visually compared with preexisting 1.5T MR images from the same patients.

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Imaging of the Region of the Osteochondral Junction (OCJ) Using a 3D Adiabatic Inversion Recovery Prepared Ultrashort Echo Time Cones (3D IR-UTE Cones) Sequence at 3T
Ya-Jun Ma1, Saeed Jerban1, Michael Carl2, Lidi Wan1, Tan Guo1, Hyungseok Jang1, Graeme Bydder 1, Eric Chang1,3, and Jiang Du1

1Radiology, University of California, San Diego, San Diego, CA, United States, 2GE health care, San Diego, CA, United States, 3VA San Diego Healthcare System, San Diego, CA, United States

The osteochondral junction (OCJ) region serves as a functional barrier between the synovial joint space and subchondral bone marrow, and may play an important role in the pathogenesis of osteoarthritis (OA). MRI of the OCJ region is difficult due to the short T2 of deep radial uncalcified cartilage and calcified cartilage, which results in little or no signal when conventional pulse sequences are used. The purpose of this study was to use a 3D adiabatic inversion recovery prepared UTE Cones (3D IR-UTE-Cones) sequence for volumetric imaging of OCJ region with high spatial resolution and contrast in clinically acceptable scan times. 

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Predicting Pain Trajectories in Knee Osteoarthritis Subjects by Learning Image Biomarkers from Structural MRI
Jinhee Jenny Lee1, Felix Liu1, Sharmila Majumdar1, and Valentina Pedoia1

1University of California, San Fransisco, San Fransisco, CA, United States

The relationship between image biomarkers in structural MRI and knee osteoarthritis pain progression is investigated. A Bayesian Gaussian mixture model is selected to identify the distinct knee pain trajectories among subjects in the dataset from the Osteoarthritis Initiative. Deep learning is employed to predict the probability of an individual’s pain curve cluster membership using the 3D structural MRI. Utilizing the strength of the model-based approach, the pain curves are simulated from the GMM posterior probabilities and the weights learned to evaluate the 3D DenseNet’s performance. 

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Usefulness of Magnetic Resonance Texture Analysis for Differentiation between Recurrent Disc Herniation and Postoperative Epidural Fibrosis
Seong Jong Yun1, Wook Jin1, Na-Young Choi1, and Kyung Nam Ryu2

1Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Korea, Republic of, 2Department of Radiology, Kyung Hee University Hospital, Seoul, Korea, Republic of

Although magnetic resonance (MR) with contrast-enhancement has been used as standard imaging tool for distinguishing recurrent disc herniation from postoperative epidural fibrosis, it is relatively invasive and vulnerable to contrast material-related complication. Also, the differentiation between recurrent disc herniation and postoperative epidural fibrosis on non-enhanced MR is not always clear. Until now, no study has evaluated the diagnostic usefulness of MR texture analysis (MRTA) for differentiation between recurrent disc herniation from postoperative epidural fibrosis. Therefore, the purpose of this study is to evaluate the usefulness of MRTA for differentiation between recurrent disc herniation from postoperative epidural fibrosis. Regarding mean, skewness, MPP, and entropy, values on all sequences were significantly lower in recurrent disc herniation than those in postoperative epidural fibrosis (p<0.001). The best performing MRTA parameters were MPP on T2WI (AUC, 0.81; 95 % CI, 0.72-0.90) and on T1WI (AUC, 0.80; 95 % CI, 0.70- 0.88). There were excellent interobserver agreements for all measurements (ICC, 0.838–0.905).

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3D Multi-spectral T2 Mapping Near Metal Implants
Sampada Bhave1, S. Sivaram Kaushik2, Matthew F Koff3, Hollis G Potter3, and Kevin M Koch1

1Medical College of Wisconsin, Milwaukee, WI, United States, 2GE Healthcare, Waukesha, WI, United States, 3Hospital for Special Surgery, New York, NY, United States

The need for examining tissue integrity near metal implants in post-operative arthroplasty is rapidly increasing. Quantitative T2 mapping can be beneficial for characterization of tissues and early diagnosis of tissue pathology. Current T2 mapping techniques lack the capability to image near metal hardware. A novel 3D fast spin echo based two-echo multi-spectral T2 mapping technique is proposed to address this need. This technique is compared to the commercially available approach for accuracy of relaxometry measurements both in phantom and human experiments.

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Texture analysis based on T2WI, DWI and delayed T1-enhanced imaging for the differentiation of benign and malignant bone tumors
Ying Li1, Cuiping Ren1, Jingliang Cheng1, and Zhizheng Zhuo2

1First affiliated hospital of Zhengzhou university, Zhengzhou, China, 2Clinical Science, Philips Healthcare, Beijing, China

With the development of MR techniques, the T2WI, DWI and delayed T1-enhanced imaging techniques have applied as the necessary and general clinical scanning sequences for the bone tumors. And the tumors would present a specific intensity distribution for a specific modality of these high resolution images. Therefore, this work investigated and evaluated the role of textures extracted from T2WI, DWI and delayed T1-enhanced imaging in characterizing the subtypes of bone tumors, and furtherly evaluate the ability of these textures to differentiate benign and malignant tumorsby using support vector machine classifier1 (SVM), which might be helpful for clinical diagnosis and studies.Results showed that the texture parameters extracted from these images have the ability to distinguish benign from malignant bone tumors based on SVM.  

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MRI Off-Resonance Analysis Correlates with Histology Necrosis Observations in Failed Total Hip Arthroplasty
Kevin Koch1, Juan Liu2, Matthew F Koff3, and Hollis Potter3

1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 2Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, United States, 3Magnetic Resonance Imaging, Hospital for Special Surgery, New York, NY, United States

This study presents the analysis of 78 total hip arthroplasty revision subjects that underwent advanced MRI off-resonance analysis and optical histology necrosis grading of tissue biopsies.   The off-resonance analysis, which leverages multi-spectral MRI methods, sought to quantify metal particle deposition in tissues or “metallosis”.   Direct measurements of off-resonance signatures correlated strongly with histology necrosis grade (p < 0.013).   The results of this study provide encouragement that quantitative MRI may be useful as a non-invasive biomarker of tissue destruction in symptomatic total hip arthroplasty.  

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Computer Aided Detection of Synovial Abnormalities Near Total Hip Replacements on 3D-MSI MRI using Deep Neural Networks
Kevin Koch1, Ruben Stern2,3, Robin Karr1, Andrew Nencka1, Matthew F Koff2, and Hollis Potter2

1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 2Magnetic Resonance Imaging, Hospital for Special Surgery, New York, NY, United States, 3Center for Data Science, New York University, New York, NY, United States

3D-MSI increases the visibility of a large number of important pathologies commonly found near implanted orthopaedic hardware, including: host-mediated adverse local tissue reactions,  infection, osteolysis, and osteonecrosis. MRI identification of these pathologies aids in planning for surgical revision and has been shown capable of predicting tissue destruction in symptomatic hip replacements.  Identification of these features is difficult, even for the interpreting physicians with substantial specialized training and experience .     To address this current challenge, a deep-learning based pattern classification approach using 3D-MSI MRI is proposed and demonstrated to predict patterns of adverse synovial responses near hip replacements.

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A Comprehensive Gradient Trajectory Correction Strategy for Clinical 3D UTE Imaging
Qi Liu1, Bo Li2, Xiaomao Gong2, Chunjing Tang2, Jian Xu1, and Weiguo Zhang1

1UIH America, Inc, Houston, TX, United States, 2Shanghai United Imaging Healthcare Co., Ltd, Shanghai, China

A comprehensive gradient trajectory correction strategy for non-selective 3D radial UTE imaging was proposed that consistently produces images free of gradient related artifacts by incorporating the actual gradient waveform, and features user friendliness and time-saving by removing the need for separate calibration scan. Application of this innovative design on phantom and volunteer imaging indicates it is a robust and promising technique.

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Intervertebral Disc Mechanics Measured by dualMRI In Vivo
Robert L. Wilson1, Leah Bowen1, Woong Kim2, Luyao Cai2, and Corey P. Neu1,2

1Mechanical Engineering, University Of Colorado Boulder, Boulder, CO, United States, 2Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States

Functional imaging of intratissue strain in intervertebral discs (IVD) provides an opportunity to investigate tissue in vivo. For the first time, we utilized displacement under applied load MRI (dualMRI) to document principal strains of healthy cervical IVDs in vivo. The transverse and shear average and maximum strains showed position-dependent responses. Additionally, we compared dualMRI results to conventional T2 and T1ρ MRI metrics. No qualitative trend was observed in the conventional MRI data, highlighting the potentially increased sensitivity of dualMRI. In vivo dualMRI may prove a valuable tool to noninvasively investigate IVD biomechanics through strain characterization, leading to better tissue evaluation.

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Image denoising with deep transfer learning for screening baseball elbow injuries using portable scanners
Mayu Nakagomi1, Sodai Hoshiai2, Yoshikazu Okamoto2, and Yasuhiko Terada1

1Institute of Applied Physics, Tsukuba, Japan, 2Comprehensive Human Sciences, Tsukuba, Japan

Portable MRI scanners have the advantages of maximizing clinical availability in remote environments. We have recently developed a portable, elbow scanner installed in a standard-size car. This system allows us to detect early symptoms of baseball elbow in remote places, but it often suffers from the low signal-to-noise ratio in noisy, outdoor environments. Here we proposed a deep-learning based approach, a denoising convolutional neural network with transfer learning, for denoising images of the potable scanner. We verified that the proposed denoising technique improved the quality of noisy images and increased the clinical feasibility of the portable scanner.

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Clinical Feasibility of MAVRIC Based T2 Mapping Near Total Hip Arthroplasty
Jacky Cheung1, Mauro A. Miranda1, Kelly C. Zochowski1, Sampada Bhave2, Hollis G. Potter1, Kevin M. Koch2, and Matthew F. Koff1

1Hospital for Special Surgery, New York, NY, United States, 2Medical College of Wisconsin, Milwaukee, WI, United States

Morphologic MRI is commonly performed to assess the presence and extent of abnormal synovial reaction in total hip arthroplasty (THA) but relies on the reader’s training for an accurate diagnosis. Newly developed quantitative methods, including MAVRIC based T2 mapping, may provide a quantitative means for assessing synovial reactions. This study performed MAVRIC based T2 mapping on individuals with THA. Prolonged T2 values were found in subjects with synovitis. This study displays the feasibility of MAVRIC based T2 mapping near THA.

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Automated Cartilage and Meniscus Segmentation of Knee MRI with Conditional Generative Adversarial Nets
Sibaji Gaj1, Mingrui Yang1, Kunio Nakamura1, and Xiaojuan Li1

1Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, United States

Clinical translation of quantitative MRI techniques requires accurate cartilage and tissue segmentation. In this work, we have developed and tested a fully automated cartilage and meniscus segmentation model for knee joint using deep learning. To improve segmentation performance by incorporating multi-scale spatial constraints in objective function, the proposed model combines CGAN and U-Net and the dice and cross-entropy loss are added to the CGAN’s objective function. The segmentation performance has been improved for all six compartments and the average dice coefficient for segmentation during testing is 0.88 compared to 0.79 of existing U-Net based segmentation.  

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Effects of trajectory and k-space undersampling in Compressed Sensing-Parallel Imaging 3D-GRASE
Alexandra Cristobal-Huerta1, Dirk H.J. Poot1,2, Mika Vogel3, and Juan A. Hernandez-Tamames1

1Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands, 2Medical Informatics, Erasmus MC, Rotterdam, Netherlands, 3Healthcare Systems, GE Healthcare, Hoevelaken, Netherlands

Compressed sensing parallel imaging (CSPI) 3D-GRASE can reduce the acquisition time compared to CSPI 3D-FSE. Image quality of 3D-GRASE strongly depends on the sampling pattern used, since gradient-echoes (GREs) and spin-echo (SE) are combined in the same k-space. Moreover, successful CSPI relies on appropiate incoherent sampling patterns.

In this work we propose and investigate the influence of several sampling patterns on coherence and in-vivo image quality of $$$PD$$$-weighted knee CSPI 3D-GRASE. With the best sampling pattern CSPI 3D-GRASE obtain high image quality with significantly reduced acquisition time (57%) and SAR (66%) compared to CSPI 3D-FSE acquisitions.


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DANTE-SPACE-based imaging of the brachial plexus
Xiaoyong Zhang1, Liqi Yang2, Guijin Li3, Yan Li2, Bei Li2, Yi Sun4, Chenhui Li3, John Grinstead 5, Guoxi Xie6, and Xin Liu7

1MR Collaborations, Siemens Healthcare Ltd., Shenzhen, China, 2BGI, Shenzhen, China, 3Siemens Healthcare Ltd., Guangzhou, China, 4MR Collaborations, Siemens Healthcare Ltd., Shanghai, China, 5Siemens Healthcare GmbH, Erlangen, Germany, 6Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou, China, 7Shenzhen Institutes of Advanced Technology, Shenzhen, China

Magnetic resonance neurography (MRN) has been increasingly used to evaluate brachial plexopathy. However, MRN is limited by the lack of relative contrast between nerves and their surrounding tissues. As an alternative to MRN, T2-SPACE has been proposed as a black-blood technique that permits more direct visualization of the brachial plexus; however, it has similar limitations. A preliminary study demonstrated that T2-weighted DANTE-SPACE outperformed SPACE and might be a potential alternative for the visualization of the brachial plexus. In this study, we hypothesized that T2-weighted DANTE-SPACE would address the above issue due to its superior blood flow suppression.


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Feasibility of bright-bone cervical spine MRI using Zero TE sequence at 3T
Aiming Lu1, Joel P Felmlee1, Krzysztof R Gorny1, David F Kallmes1, Peter D Kollasch2, and Carrie M Carr1

1Radiology, Mayo Clinic, Rochester, MN, United States, 2Siemens Healthcare, Rochester, MN, United States

Direct visualization of solid cortical bone structures with MRI is gaining increased interest. “Bright-bone” techniques based on ultrashort echo time (UTE) and Zero TE (ZTE) sequences enable obtaining signals from the cortical bone and are thus desirable for visualizing cortical bone. This work demonstrated that high quality cortical bone imaging of the human skull and c-spine can be achieved on a clinical 3T scanner in a reasonable acquisition time (<6 minutes). This can potentially widen the usage of MRI for C-spine imaging.

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Quantitative MRI to assess disease activity change in children with juvenile idiopathic arthritis
Joshua Luke Bennett1, Amanda Wood1, Nicola Smith2, Ravi Mistry3, Karen Allen1, Sharmila Jandial1, John Mark Tuckett4, Claire Gowdy5, Helen E Foster1,2, Flora McErlane1,2, and Kieren Grant Hollingsworth2

1Paediatric Rheumatology, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom, 2Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom, 3Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom, 4Radiology, Freeman Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom, 5Paediatric Radiology, British Columbia Children's Hospital, Vancouver, BC, Canada

Assessment of disease activity in children with juvenile idiopathic arthritis (JIA) is central to avoiding permanent joint damage. Affected joints are characterised by synovial proliferation resulting in synovial effusion and hypertrophy. Long-standing poorly controlled synovitis is associated with a high frequency of joint damage. 11 children with JIA were examined with quantitative MRI to measure synovial volume and rate of contrast uptake before and 12 weeks after routine intra-articular corticosteroid injection. All children showed marked reductions in synovial volumes, and in rates of uptake of gadolinium. These reductions were more consistent than changes in clinical assessments.

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Visualization and quantification of epiphyseal cartilage vasculature using quantitative susceptibility maps of pediatric knee specimens
Kai D. Ludwig1,2, John Strupp1,2, Casey P. Johnson1,2, Stefan Zbyn1,2, Mikko J. Nissi1,2,3, Ferenc Tóth4, Kevin Shea5, Cathy S. Carlson6, and Jutta M. Ellermann1,2

1Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, United States, 2Radiology, University of Minnesota, Minneapolis, MN, United States, 3Applied Physics, University of Eastern Finland, Kuopio, Finland, 4Veterinary Population Medicine, University of Minnesota, St. Paul, MN, United States, 5Orthopaedic Surgery, Stanford University, Stanford, CA, United States, 6Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, United States

Visualization of the vasculature within the epiphyseal cartilage of the distal femur of the skeletally immature knee joint is possible with susceptibility-weighted MRI. A post-processing pipeline is described to segment and quantify the vascular density within two distinct vascular beds of the distal femoral epiphyseal cartilage using quantitative susceptibility maps. The described post-processing may allow identification of vascular abnormalities at early stages of development and also may improve assessment of therapeutic interventions.

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A Prospective, Longitudinal Assessment of Adverse Local Tissue Reactions in Resurfacing Hip Arthroplasty Versus Primary Total Hip Arthroplasty in Asymptomatic Subjects
Matthew F. Koff1, Mauro Miranda1, Jacky Cheung1, Kelly Zochowski1, Bin Lin1, Edwin Su1, Douglas Padgett1, and Hollis G. Potter1

1Hospital for Special Surgery, New York, NY, United States

This prospective study compares the prevalence of MRI detected adverse local tissue reactions (ALTRs) in metal-on-polyethylene (MoP), metal-on-metal hip resurfacing arthroplasty (HRA), and ceramic-on-polyethylene (CoP) total hip arthroplasty subjects. Images acquired at four time points with a 1-year interval showed a higher prevalence of ALTRs in the HRA than CoP or MoP subjects. Self-assessed symptomatology scores did not significantly differ by implant type at follow-up, indicating that ATLRs can be clinically silent. This study permits better understanding of the natural history of ALTRs complicating hip arthroplasty. 

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T1ρ and T2 Relaxation Times are Sensitive to Ischemic Injury in Femoral Head Specimens from a Piglet Model of Avascular Necrosis Independent of a Freeze/Thaw Cycle
Casey P. Johnson1,2, Ferenc Toth3, Cathy S. Carlson4, Stefan Zbyn1,2, Kai D. Ludwig1,2, Harry K. W. Kim5,6, and Jutta M. Ellermann1,2

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 3Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, United States, 4Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, MN, United States, 5Texas Scottish Rite Hospital, Dallas, TX, United States, 6Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, TX, United States

We investigated whether T1, T2, and T1ρ mapping can detect early ischemic injury to bone, marrow, and cartilage in an animal model of femoral head avascular necrosis. We imaged and compared six pairs of freshly-harvested ischemic and control femoral head specimens. We then imaged the specimens a second time after a freeze/thaw cycle. We found that T1ρ and T2 mapping were sensitive to ischemic injury to the femoral heads 48 hours after onset of ischemia. Furthermore, this sensitivity was maintained after the freeze/thaw cycle. This work indicates that T1ρ and T2 mapping may help assess ischemic bone and joint disorders.

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Scan Time Reduction in High Resolution Knee Imaging using Compressed Sensing and Denoising Deep Learning Reconstruction
Mitsue Miyazaki1,2, Masaaki Umeda2, Shinichi Kitane2, Cheng Ouyang1, Sheronda Statum1,3, Won C Bae1,3, and Christine Chung1,3

1Radiology, UCSD, La Jolla, CA, United States, 2Canon Medical Systems Corp., Otawara, Japan, 3VA San Diego Healthcare System, La Jolla, CA, United States

Compressed sensing (CS) uses undersampling at the expense of image blurring and increased noise. We have developed denoising deep learning reconstruction (dDLR) to reduce noise and regain signal-to-noise ratio (SNR) in highly undersampled (4-4.5x) CS images. Feasibility study was performed in fat-suppressed T2 and proton density knee images, by evaluating SNR and image quality (sharpness, blurring, and artifact scores). Compared to reference (no CS or dDLR), images obtained with CS had lower SNR (by 25 to 40%) and image scores due to sharpness and blurring. After processing with dDLR, SNR and image scores were restored the reference levels.

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Use of passive B1+ shimming via dielectric pads for uniformity improvements in 7T clinical knee imaging
Andrew J Fagan1, Kimberly K Amrami1, Matthew A Frick1, Benjamin M Howe1, Peter Kollasch2, Venkata Chebrolu2, and Joel P Felmlee1

1Radiology, Mayo Clinic, Rochester, MN, United States, 2Siemens Healthineers, Rochester, MN, United States

Passive B1+ shimming was performed using custom dielectric pads to improve image uniformity for clinical knee imaging at 7T.  Image non-uniformity is problematic for diagnosing knee pathologies, and post-processing solutions are limited at 7T due to the lack of a uniform body transmit coil.  A range of pads made from high permittivity perovskite materials were fabricated and tested on 6 subjects.  An optimal configuration was determined, comprising the pad dimensions and composition, commensurate with producing optimal image uniformity while fitting all subjects scanned.  Dielectric pads represent an easy-to-use solution for improving clinical image uniformity at 7T.

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An approach to validate MRI Compatible axial Knee joint Loading Device with various standing posture in Standing MRI
Sandeep Panwar Jogi1,2, Rafeek T1, Sriram Rajan3, Dharmesh Singh1, Vidur Mahajan3, Vasantha K Venugopal3, Amit Mehndiratta1, and Anup Singh1

1Centre of Biomedical Engineering, Indian Institute of Technology Delhi, Delhi, India, 2BME, Amity Uninversity Haryana, ASET, Gurgaon, India, 3Mahajan Imaging Centre, New Delhi, India

Study of knee joint behaviour under load have a significant potential for Osteoarthritis (OA) diagnosis and monitoring. There are few reported studies on monitoring changes in knee cartilage under load using MRI. Reported process of validation of such loading device are in term repeatability and reproducibility. In this study, an approach is proposed to validate the loading-device using MRI data acquired in standing posture. OpenMRI(0.25T) was used to acquire data in various postures and results were compared with 3T-MRI data with and without load reliability and accuracy of various measurements such as bone-gap, cartilage-thickness and T2-values were evaluated.

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Evaluating Intraarticular Bleeding of Haemophilic Arthropathy Using Quantitative Susceptibility Mapping
Fang Zhou1, Yihao Guo2, Caixia Li1, Jing Sun3, Yingjie Mei4, Yanqiu Feng2, and Yikai Xu1

1Department of Medical Imaging,Nanfang Hospital,Southern Medical University, Guangzhou, China, 2School of Biomedical Engineering, Guangdong Provincial Key Laborary of Medical Image Processing, Southern Medical University, Guangzhou, China, 3Department of Hematology, Nanfang Hospital, Southern Medical University, Guangzhou, China, 4Philips Healthcare, Guangzhou, China

This work aims to explore the clinical application of quantitative susceptibility mapping (QSM) in evaluating the haemarrhrosis of heamophilic arthropathy with large heamosiderin. Our results showed that there was strong correlation between QSM and bleeding time, demonstrating that QSM has the potential to be a biomarker in evaluating the intraarticular bleeding of heamophilic arthropathy with large heamosiderin.

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Feasibility and Repeatability of MR Fingerprinting in Knee Joints
Mingrui Yang1, Jeehun Kim1,2, Vikas Gulani3, Mark Griswold3, Xiaojuan Li1, and Dan Ma3

1Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, Cleveland, OH, United States, 2Electrical Engineering, Case Western Reserve University, Cleveland, OH, United States, 3Radiology, Case Western Reserve University, Cleveland, OH, United States

There is an increasing clinical need for improving early diagnosis and evaluation of early response after interventions and treatment in musculoskeletal disorders. Quantitative MRI is a promising tool towards these goals. However, quantifying relaxation times normally requires long acquisition time and is prone to B0 and B1 inhomogeneity and other imperfections. Moreover, it is difficult to optimize the acquisition parameters of conventional relaxation time imaging sequences to provide accurate T1 and T2 quantifications with a large range. MR fingerprinting (MRF) is a recently developed technique, which enables fast imaging and quantification of multiple tissue parameters simultaneously, and shows promising results in neural, body and cardiac imaging. However, the application of MRF to MSK imaging is very limited. The goal of this study was to demonstrate the feasibility and quantification repeatability of MRF in knee joints.


Engineering Safety, Applications & Computation

Exhibition Hall
Monday 9:15 - 10:15
 Engineering

1434
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Safety of Intrathecal Administration of Gadolinium-based Contrast Agents – A Systematic Review and Meta-analysis
Mihilkumar Patel1,2 and Santanu Chakraborty1,3

1University of Ottawa, Ottawa, ON, Canada, 2The Ottawa Hospital, Ottawa, ON, Canada, 3Neuroradiology, The Ottawa Hospital, Ottawa, ON, Canada

Visualizing CSF related disease processes using MRI requires the use of intrathecally administered Gadolinium-based Contrast Agents (GBCAs). MR cisternogram with GBCAs has shown to provide superior image quality compared to CT cisternogram. However, the lack of sufficient safety evidence limits its use to an off-label use. To address this, we performed a systematic review and meta-analysis to explore adverse events after intrathecal GBCA exposure. Based on our analysis, the overall incidence of serious adverse events was 2.24% with lower incidence at lower doses. We conclude that intrathecal use of GBCAs for MR imaging is safe at low doses.

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Reducing Patient Anxiety in MRI using Acoustic Noise-Modulated Computer Animations: Experience in Pediatric Psychiatric Patients
Refaat E Gabr1 and Ponnada A Narayana1

1Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, United States

Acoustic noise is a major source of discomfort and anxiety for patients undergoing MRI examination, and psychiatric patients are especially vulnerable to this stressor. We implemented a simple and low-cost system for patient distraction using visual animations synchronized to the acoustic noise caused by MRI scanner gradients. This multisensory approach, linking sensory to visual inputs, was implemented on a 3 Tesla scanner and tested in 13 pediatric patients with bipolar disorder. Another group of 15 patients received only music as a control. After the scans were completed, all subjects responded to a questionnaire, with the help of their parents, about their scan experience.  Analysis shows that the multisensory input was perceived less favorably by the patient despite the scan duration was perceived to be 15% shorter.

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Characterization of health and technological risks posed by the quench of a human high-field Magnetic Resonance system
Nicola Pace1, Leonardo Ricci2, Mario Scotoni2, Alessio Perinelli2, and Jorge Jovicich1

1CIMeC, University of Trento, Trento, Italy, 2Dept of Physics, University of Trento, Trento, Italy

The programmed quench of a human 4T MR scanner was used to measure dB/dt inside the bore to evaluate cardiac stimulation risks during a quench. Additionally, we measured the exit temperature of the helium gas, to evaluate potential implications in quench pipe design. The maximum dB/dt was 360 mTs−1 at the center of the magnet, far below the cardiac stimulation threshold (20 Ts−1). Helium exit temperature reached 35°K, perhaps implying further considerations about quench pipe design and building. Replication of similar experiments on programmed quenches, specially in high-field MRI systems, will be useful to further characterize quench risks.

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Impact of Huygens Box in 3T MRI RF Safety Assessment
Xin Huang1, Xi Lin Chen2, and Shiloh Sison1

1Abbott, Sunnyvale, CA, United States, 2Abbott, Sylmar, CA, United States

Huygens Box is an efficient simulation technique to reduce simulation time and storage space. This paper uses simulations to investigate the impact of Huygens box on 3T MRI RF Safety Assessment. The numerical results on ASTM phantom shows the overall Symmetric Mean Absolute Percentage Error (SMAPE) average on typical MRI RF simulation is 6.28%.

1438
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A subtle reaction of neonatal cochlear function after exposure to 3.0T MRI noise with hearing protection
Huifang Zhao1, Chao Jin1, Peiyao Chen1, Heng Liu1, Xiaoyu Wang1, Yannan Cheng1, Xingxing Tao1, Yuli Zhang1, Fan Wu1, Cong Tian1, Xiaocheng Wei2, and Jian Yang1

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

Although 3.0T MRI has been increasingly used for neonates, the strong noise remains a great concern. This study aimed to estimate the effect of MRI noise on neonatal cochlear function. Thirty ears of 17 patients with no hearing impairment were enrolled. Distortion product OAE (DPOAE) tests were performed to estimate the cochlear function. Significant increase of mean DPOAE amplitude by 1.13 dB at 3kHz was found within 30 minutes after MRI. Besides, standard deviations of DPOAE amplitude differences remarkably increased. A subtle reaction in cochlear function was found in neonates after exposure to 3.0T MRI noise with hearing protection.

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Assessment of RF energy-induced temperature elevation in a human thigh in vivo using MR diffusion tensor imaging
Youngseob Seo1 and Zhiyue Wang2

1Korea Research Institute of Standards & Science, Daejeon, Korea, Republic of, 2University of Texas Southwestern Medical Center, Dallas, TX, United States

The feasibility of evaluating RF heating-induced temperature elevation in a human thigh in vivo during MRI was demonstrated . RF heating-induced temperature elevation in human thighs can be assessed in vivo during MRI.  Reliable knowledge of RF heating allows safe and optimal utilization of MRI techniques.  RF heating during MRI could change the observed mean diffusivity value and affects clinical interpretation of the results.

1440
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A MRI Gradient Induced Electric Field Exposure System for Active Implanted Medical Devices
Xiyao Xin1, Xi Lin Chen1, Xin Huang1, and Shiloh Sison1

1Abbott Laboratories, Sylmar, CA, United States

MRI gradient field can produce electric field (E-field) in a patient during MR scan. For patient with active implanted medical device (AIMD), damage and malfunction are the possible outcomes due to such exposure. The ISO/TS 10974 radiated immunity test method in Clause 16 focuses on producing radiated gradient field (dB/dt) exposure. This abstract proposes a test method which directly exposes AIMD to gradient frequency E-field, offering a controlled gradient frequency E-field exposure environment for AIMD MR conditional testing.

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Uncertainty Analysis of Torque Measurement Methods Described in ASTM F2213-17
Xiao Fan Ding1,2, William B. Handler1, and Blaine A. Chronik1,2

1The xMR Labs, Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada, 2Department of Medical Biophysics, University of Western Ontario, London, ON, Canada

With the prevalence of medical implants and MRI both on the rise around the world; patients, device manufacturers, and medical professionals alike should know how implants interact with the MR environment. One such interaction is the possibility of torque on an implant due to interaction with the main field. The current methods for measuring induced torque are published by ASTM International. However, although methods are available, their accuracy and precision have yet to be properly studied. This abstract investigates the measurement uncertainties of the two methods for measuring magnetically induced torque published in the test standard, ASTM F2213-17.

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Neurological and Neuropsychological Status of Patients with Numerous Applications of Gadolinium-Based Contrast Agents. Follow up of 14-16 Years
Josef Vymazal1, Lenka Kramska2, Hana Brozova3, and Aaron M Rulseh1

1Radiology, Na Homolce Hospital, Prague, Czech Republic, 2Neurology, Na Homolce Hospital, Prague, Czech Republic, 3Neurology, Charles University in Prague, Prague, Czech Republic

Gadolinium deposition in the brain following gadolinium-based contrast agents (GBCA) application has become an important safety concern, however investigations into the effect of gadolinium deposition remain limited. We performed neurological and neuropsychological evaluation in four patients that received very high cumulative doses of linear and macrocyclic GBCAs (mean 728.25 ml, range 562–915 ml) over a range of 14–16 years. Although increased T1 signal was observed in the globus pallidus and dentate nuclei of all patients, the neurological status did not change. No signs of extrapyramidal symptomatology were detected, nor did neuropsychological testing reveal any relevant impairment implicating involvement.

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An Initial Simulation Study of Breast Implants for Clinical Breast MRI
Xin Li1, Xin Chen2, Michael Steckner2, and Joseph Rispoli1,3,4

1Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 2Canon Medical Research USA, Mayfield Village, OH, United States, 3School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States, 4Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, United States

Breast augmentation continues to be the #1 cosmetic surgery for women, with approximately 4% of the US female adult population receiving an implant. Additionally, implants are commonly employed for breast reconstruction following mastectomy. Estimating from MR procedure statistics, the breast may be in the imaging volume for up to 10% of all US MRI procedures. This abstract investigates the implications of breast implants (silicone or saline composition with a wide range of conductive properties) on patient safety and suggests there are minimal effects on local (10-g average) SAR and B1 fields.

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Shielded hybrid coil array
Ming Lu1, John C. Gore2,3,4, and Xinqiang Yan2,3

1College of nuclear equipment and nuclear engineering, Yantai University, Yantai, China, 2Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 3Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States, 4Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States

Two major factors that limit the performance of Rx coil arrays are restrictions on coil geometry and numbers. For the widely used L/C loop array, each loops’ size has to be reduced to achieve an increased number of coils. An alternative approach is to use hybrid coils which combine loops with other resonator shapes such as a figure-of-8 coil, butterfly coil, microstrip or dipole. However, the coupling between elements in hybrid coil arrays proves to be challenging due to the proximity of more coil elements. To solve this problem, we propose a novel design named “shielded hybrid coil” which combines hybrid loop+figure-of-8 resonators with circumferential shielding. We proposed two kinds of shielded hybrid resonator arrays (inner- or outer-pick-up) that exhibit an obvious Rx-performance improvement compared to conventional loop arrays. We also find that the Rx-performance is better with outer-pick-up. 

1445
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A 15-Channel Loop Dipole Array for In Vivo Swine Head MR Imaging at 10.5T
Nader Tavaf1,2, Russell L. Lagore2, Sean Moen2, Adrienne Watson3, Michael Garwood 2, Dee Koski 2, Alex Coutts 3, Kamil Ugurbil2, Gregor Adriany2, and Pierre-Francois Van de Moortele2

1Biomedical Engineering, University of Minnesota Twin Cities, Minneapolis, MN, United States, 2Center for Magnetic Resonance Research (CMRR), University of Minnesota Twin Cities, Minneapolis, MN, United States, 3Recombinetics, St. Paul, MN, United States

Novel RF coil designs must address ultra high field MRI challenges and simultaneously exploit benefits thereof in terms of higher signal-to-noise ratio and reduced acquisition time. A 15-channel RF array was built composed of a 7-channel loop receive array and an 8-channel dipole transceiver array with the receive array designed to be scalable to high density arrays. Transmit B1 maps demonstrated transmit field immunity to receive array insertion. The absolute SNR generated by the loop array receiver is on average 2.65 times the absolute SNR of the dipole transceiver in locations near the receiver array. The coil was successfully used in combination with dipole transceivers to acquire in-vivo swine brain anatomical images at 10.5T.


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Simulation comparison of 28 different 31P arrays for cardiac MR spectroscopy at 7 T
Sigrun Goluch-Roat1, Martin Vit1,2,3, Albrecht Ingo Schmid1, and Elmar Laistler1

1Division MR Physics, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, 2TUL (Technical University of Liberec), Liberec, Czech Republic, 3IKEM (Institute for Clinical and Experimental Medicine), Praha, Czech Republic

31P-MR spectroscopy measures cardiac energetics in vivo directly by means of ATP and PCr, but is limited due to low SNR due to the low MR sensitivity of the 31P nucleus and limitation by the achievable B1+. Comprehensive RF coil design considerations and planning help fully exploit the SNR gain by increase of B0. In this simulation study we compare 28 different 31P 7T RF coil array designs with respect to their transmit field performance and obtain a 3-channel array as the best variant.

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An electronically tunable X-nuclei surface coil with high impedance broadband LNA
Andreas Horneff1, Michael Eder1, Erich Hell2, Johannes Ulrici3, Benedikt Schlecker4, Jens Anders4, and Volker Rasche1

1Experimental Cardiovascular MRI, Ulm University Medical Center, Ulm, Germany, 2GM, Sirona Dental Systems, Bensheim, Germany, 3GME, Sirona Dental Systems, Bensheim, Germany, 4Institute of Smart Sensors, University of Stuttgart, Stuttgart, Germany

In this approach, we present an electronically tunable surface coil in combination with a high impedance broadband LNA for X-nuclei MRI experiments with a bandwidth between 34MHz and 104MHz. The performance of the approach was evaluated by comparison with a state of the art LNA / surface coil reference setup for hydrogen and fluorine imaging. The resulting SNR reduction was less than 4% and a mean value and standard deviation of the relative error of the sensitivity map between the reference setup and the proposed setup of µ=0.4% and σ=1.4% was observed.

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Design of large-size, high-frequency, loop-type surface coil using dipole antennas for ultrahigh filed MR imaging: a feasibility study at 400MHz and 600MHz
Shasha Yue1 and Xiaoliang Zhang2,3

1Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, 3UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, United States

Due to the parasitic capacitance and increased inductance, building large-size high frequency RF coils, including surface coils for human MR imaging applications at ultrahigh fields, is a challenge. By taking the advantage of high frequency capability and large size of dipole antennas, in this work, we propose a novel surface coil design method using the proposed V-shaped dipole antennas for large-size, high-frequency, loop-type surface coils in ultrahigh field MR applications in humans. The results show that the proposed large size loop-type dipole surface coils (~20cm or ~16cm diameter) have the potential to generate common B1 field distributions of traditional loop-type surface coils at 9.4T (400MHz) and 14T (600MHz). This opens up the possibility of constructing high frequency large size surface coils for ultrahigh field MR imaging in humans.

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A new non-array volume coil structure using the right-angled-end dipole antenna for ultrahigh field MR
Shasha Yue1, Luo Chao2,3, Zhe Wang1, Yan Hou1, Ye Li2,3, and Xiaoliang Zhang4,5

1Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 2Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 3Shenzhen Key Laboratory for MRI, Shenzhen, China, 4Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, 5UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, United States

Previous work demonstrated that it is feasible to design non-array volume coils using the coupled dipole antennas. However, the weak coupling of the standard dipoles and over-length make the design difficult and also limit its utility. In this work, we propose a modified dipole structure which can be used for high frequency non-array volume coils with improved coupling. It also provides certain flexibility in coil length control. Results of the proposed design at 400 MHz and 500MHz (i.e. 9.4T and 11.7T) are presented. 

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Calibrated Coil Combination for Fixed-Geometry, Low-Frequency Coils with Application to Hyperpolarized 13C Measurements
Juan Diego Sánchez Heredia1, Rie B. Hansen1, Rafael Baron1, Esben S. Szocska Hansen2, Daniel H. Johansen1, Vitaliy Zhurbenko1, Christoffer Laustsen2, Lars G. Hanson1, and Jan H. Ardenkjær-Larsen1

1Department of Electrical Engineering, Technical University of Denmark (DTU), Kgs. Lyngby, Denmark, 2MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark

We explore a new design approach for low frequency RF coils, where a transmit and receive array are built together in a totally rigid frame, and therefore their B1+ and B1- distributions can be accurately mapped and used as prior information for SNR-optimal combination of signals from different coil elements. Using this principle, a coil is designed for 13C MRS of a pig at 3T (32.13 MHz). We show that at this frequency, the effect of sample loading is minimal, and the prior information obtained in phantoms benefits in-vivo experiments. This one-time calibration allows for optimal combination of coil signals, which is also expected to improve parallel imaging performance.

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A modular 7T high-impedance array for ex-vivo imaging
Shin-Ichi Urayama1, Bei Zhang2, Koji Fujimoto3, Tomohisa Okada3, and Martijn A Cloos2

1Center for Educational Program in Graduate School, Kyoto University, Graduate School of Medicine, Kyoto, Japan, 2Radiology, New York University School of Medicine, New York, NY, United States, 3Human Brain Research Center, Kyoto University, Graduate School of Medicine, Kyoto, Japan

The high SNR provided by whole body 7T also provides enticing opportunities for ex-vivo imaging. However, such MRI systems are usually only equipped with a limited number of coils, rarely optimized for ex-vivo imaging. In this work, we leverage the new-found degrees of freedom provided by High Impedance Coil elements to create a versatile modular array-coil that can be re-configured in seconds to fit each sample optimally.

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Optimization of 4-Port Asymmetric Elliptical Birdcage RF Coil for 1.5 Tesla MRI
Suchit Kumar1, Jeong-Hee Kim2, Heung-Kyu Lee3, and Chang-Hyun Oh1,4,5,6

1Department of Biomicrosystem Technology, Korea University, Seoul, Korea, Republic of, 23Research Institute for Advanced Industrial Technology, Korea University, Sejong City, Korea, Republic of, 3Coretech Co., Ltd., Gyeonggi-do, Korea, Republic of, 4Department of Electronics and Information Engineering, Korea University, Sejong City, Korea, Republic of, 5ICT Convergence Technology Team for Health & Safety, Korea University, Sejong City, Korea, Republic of, 6Corresponding Author, ohch@korea.ac.kr, Seoul, Korea, Republic of

The elliptical whole-body radiofrequency (RF) coil can be used for RF transmission/reception in magnetic resonance (MR)-guided treatment or MR-fused system with space between the RF shield and the gradient coil available for other imaging/treatment modality. The elliptical birdcage has higher B1+ field uniformity than circular birdcage due to increased filling factor between the RF coil and target. In this work, the asymmetric elliptical birdcage is proposed to improve overall performance through electromagnetic simulations. This work compares the 2-port and 4-port excitations and their effects on B1+ field uniformity and SAR deposition for both circular and elliptical coil with symmetrical/asymmetrical structures.

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Decoupling circuit design for multi-nuclear RF coil
Seunghoon Ha1, Adam Morris1, Jay Berres1, and Jonathan Nass1

1Philips Healthcare, Pewaukee, WI, United States

The demand about invivo multi-nuclear MRI/MRS has increased according to introduction of higher tesla MR system. The development of the dual frequencies RF coil array keeps pace with this interest. At the overlay of both the proton and second-nucleus frequencies coil loops, inductive coupling between coils has resolved to retain proton sensitivity and coil tuning stability by LLC and LC tank circuit. However, they cause another mutual coupling issue between the circuits and coil loops. Therefore, we introduce a simpler and more efficient decoupling method than LLC and LC tank circuit in this study.

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Combined volume T/R and surface Rx-only coils for simultaneous brain and spinal cord imaging of squirrel monkey at 9.4 T
Xinqiang Yan1,2, Feng Wang1,2, Ken Wilkens1,2, Daniel Colvin1,2, Li Min Chen1,2, and John C. Gore1,2

1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Radiology and Radiological Science, Vanderbilt University, Nashville, TN, United States

Simultaneous imaging of spinal cord and brain potentially provides valuable information about how they work together and visualizes their interactions. However, to date, almost all image studies have investigated these two highly interconnected systems in separations, due mainly to the lack of an adequate imaging hardware. In this work, we designed and fabricated a volume T/R and surface Rx-only coil which can significantly increase the SNR around the spinal cord while simultaneously acquiring whole brain images. It needs only two receive channels and operates in a highly restricted volume, making it suitable for the small animal scanner.

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Loop Array RF Coil for Vertical Field MRI using Loop/Dipole Parallel RF Coils
Yosuke Otake1, Kohjiro Iwasawa1, Hisaaki Ochi1, Masayoshi Dohata2, and Takahide Shimoda2

1Research & Development Group, Hitachi, Ltd., Tokyo, Japan, 2Healthcare Business Unit, Hitachi, Ltd., Tokyo, Japan

To increase the SNR of an RF array coil for vertical field MRI, a loop/dipole parallel RF (LDP) coil was developed. The SNR was increased by forming a solenoid shaped current on an array coil using the LDP coils. The performance of the coils was evaluated using an electromagnetic simulator. The SNR of the LDP coil was 9% better than that of a conventional loop array coil. This technique will contribute to increasing the SNR of the array coil for vertical field MRI.

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RF-induced heating pattern of a partially immersed conducting implant wire at 7T – its dependence on wire length
Pallab K Bhattacharyya1,2, Bhumi Bhusal3, Tanvir Baig3, Mark J Lowe1, Michael Martens3, and Stephen E Jones1

1Imaging Institute, Cleveland Clinic, Cleveland, OH, United States, 2Radiology, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, United States, 3Physics, Case Western Reserve University, Cleveland, OH, United States

Radiofrequency induced heating at 7T of an insulated wire (exposed at tip) partially immersed in ASTM gel phantom to evaluate safety of scanning partially implanted guidewires, implants like   stereo electroencephalography (SEEG) electrodes at different configurations, and conducting wires at that field strength. A transmit-receive coil was used for this study. Heating at certain resonance lengths separated by half a wavelength in air was observed. The heating at resonance lengths were 3-4 times less than that reported earlier at 3T at same specific absorption rate, and under similar configurations and settings.

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Development of Asymmetric 8Tx/16Rx Coil Array for Human Cardiac MRI at 7 T: RF Shimming and SAR Safety Study
Ibrahim A. Elabyad1, M. Terekhov1, M. R. Stefanescu1, M. Fischer1, and L. M. Schreiber1

1Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany

A novel transceiver 8Tx/16Rx coil array was simulated and developed for cardiac magnetic resonance imaging (cMRI) in humans at 7T. The developed cardiac coil array consists of two independent parts, the semi-curved anterior array and the flat posterior array, each array composed of identical 8-elements. An optimization routine has been developed in MATLAB to find the optimal phases for B1+-field homogeneity with minimal local SAR values within the Duke and Ella human models. RF-shimming improves the B1+-field homogeneity by 30% and 46% for Duke and Ella, respectively. The novel cardiac pTx array has higher Tx-efficiency and flexibility in RF-shimming compared to the 1Tx commercial coil.

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Initial experience with SPOKES EPI on a 7T Terra scanner
Belinda Ding1, Iulius Dragonu2, Catarina Rua1, and Christopher T Rodgers1

1University of Cambridge, Cambridge, United Kingdom, 2Siemens UK, Frimley, United Kingdom

This abstract describes our initial experiences using the parallel transmit (pTx) mode on our recently-installed 7T Terra MRI scanner (Siemens, Germany). We acquired data from a phantom and a human volunteer with a turbo-FLASH B1-mapping sequence and an EPI sequence. We used the conventional single-channel system with a Nova 32-channel 1Tx head coil and the pTx system with a Nova 32-channel 8Tx head coil. For the parallel-transmit system, the sequences were run in both a static CP+ B1 shim mode, and with dynamic online SPOKES-2 pulse design. We report temporal signal-to-noise ratio (tSNR) statistics for each image series.


B0 Field Management & Shimming

Exhibition Hall
Monday 9:15 - 10:15
 Engineering

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Numerical assessment of a multi-coil shimming system in human brain MRI
Pei-Yan Li1, Yi-Tien Li1,2, and Fa-Hsuan Lin3,4

1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, 2Taipei Medical University - Shuang Ho Hospital, Taipei, Taiwan, 3Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 4Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland

We numerically evaluated the performance of multi-coil shimming in human brain using an array of up to 1,000 coils with realistic off-resonance distributions of 37 healthy participants. The average and variation of shim current distributions were revealed. Singular Value Decomposition suggested orthogonal current modes to reduce off-resonance. The first 6 current modes accounted for about 90% of the variance of shim current distributions. They achieved shimming performance comparable to the 5th-order and 4th-order spherical harmonic in global and slice-selective shimming, respectively. 

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A 32-channel multi-coil shim setup optimized for the human brain, pushing the limits of shimming at 9.4T
Ali Aghaeifar1,2,3, Jiazheng Zhou1,2, Irena Zivkovic4, Joshi Walzog1, Mirsat Memaj1, Theodor Steffen1, Rahel Heule1, Feng Jia5, Maxim Zaitsev5, and Klaus Scheffler1,3

1Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany, 3Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany, 4C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands, 5Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany

Multi-coil shimming is an effective approach to reduce B0 field inhomogeneity. In this work, we optimized a 32-channel multi-coil to fit best for shimming of the human brain. The individual coils are optimized in terms of size and position. The performance is compared with the conventional symmetric design.  

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An adjustable susceptibility phantom for evaluation of field mapping and fat fraction estimation algorithms
Paul A. Picot1, Junmin Liu1, and Maria Drangova1

1Robarts Research Institute, the University of Western Ontario, London, ON, Canada

We demonstrate a method to produce phantoms with arbitrary and easily adjustable susceptibility distributions.  Objects in a magnet bore cause high order inhomogeneities not correctable by shimming, and confound magnetic field mapping and phase unwrapping algorithms.  We show a wire winding carrying direct current can simulate an object of adjustable susceptibility, for rapid testing of field mapping and phase unwrapping methods. 

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Ultimate B0 Shim and the Design of Optimal Shim Bases
Nicolas Arango1, Jason Stockmann2,3, Elfar Adalsteinsson1,4, and Jacob White1

1Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 3Harvard Medical School, Boston, MA, United States, 4Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States

Simulations providing an upper bound on ∆B0 shimming of 1096 human brains from the human connectome project with currents outside the target volume were performed and used to construct optimal n-channel shim fields. Optimal truncated shim basis performance was evaluated suggesting 70 optimal channels are required to achieve 95% of ultimate performance. Comparisons with arrays of regularly spaced circular loops suggests that under realistic current constraints, regular loop arrays with hundreds of elements only achieve 85% of ultimate performance. The ultimate ∆B 0 shim and optimal n-channel coils will be useful tools in the analysis and comparison of shim array designs.

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Analysis of B0 Eddy Current in Superconducting MRI System Involving Main Coil Circuit
Yihe Hua1, Teck Beng Desmond Yeo1, and Thomas Foo1

1GE Global Research, Niskayuna, NY, United States

The B0 eddy current, which shifts the temporal B0 and is harmful to MR Image quality, hasn’t been analyzed in detail before. In this work, we provide a FEM-circuit co-simulation method for this problem and the result clearly shows that main superconducting coil plays an important role in shaping the B0 EC time constant and thus to include them in model is necessary for making accurate prediction. 

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A short gradient coil with “outer-wall direct cooling" for human brain imaging
Hanbing Lu1, Zhi Yang2, Beihan Zhao2, Yong Pei2, and Bao Yang2

1Neuroimaging Research Branch, National Institute on Drug ABuse, NIH, Baltimore, MD, United States, 2Mechanical Engineering, University of Maryland, College Park, MD, United States

Optimal gradient performance is arguably a pre-requisite to realize the full potential of ultrahigh field MRI. The values of using tailored gradient coils for brain imaging have been well acknowledged. Unfortunately, conventional head-only gradient coils have two major technical limitations, i.e. limited shoulder clearance and limited cooling capacity. A new design, coined “auto-rim” gradient coil,  combined with a novel cooling method, named “outer-wall direct cooling”, is proposed to fundamentally solve these two technical problems. As a proof-of-concept, we have built a protype gradient coil capable of generating 20.2, 13.5 and 29.1 Gauss/cm/600 ampere current along X, Y and Z, respectively.

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Low-cost gradients using commercially-available printed circuit boards
Junpei Matsuzaki1, Tomoyuki Haishi2, and Yasuhiko Terada1

1Institute of Applied Physics, Tsukuba, Japan, 2MRTechnology Inc., Tsukuba, Japan

Gradient coils often need expensive, manufacturing processes such as gluing, etching, and/or milling. The purpose of this study is to propose low-cost gradients using commercially-available printed circuit boards (PCBs). For proof of concept, we fabricated four types of PCB-gradients for different MRI systems: cylindrical transverse gradients for a 1.5 T, 280 mm-bore superconducting magnet (SCM), for a 4.7 T, 89 mm-bore SCM, and for a 9.4 T, 54 mm-bore SCM, and planar gradients for a 0.2 T, 160 mm-gap permanent magnet. We verified that the PCB gradients outperform the hand-wound gradients.

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Numerically optimized design for a low-cost, lightweight 86mT whole-brain magnet
Patrick C McDaniel1,2, Clarissa Zimmerman Cooley2, Jason P Stockmann2, and Lawrence L Wald2,3

1Massachusetts Institute of Technology, Cambridge, MA, United States, 2Athinoula A Martinos Center for Biomedical Imaging, Charleston, MA, United States, 3Harvard Medical School, Boston, MA, United States

Whole-brain imaging is a major use of MRI, but the cost and siting requirements of scanners limit its use. Here, we propose a close-fitting, lightweight, whole-brain MRI system to address these limitations. We design the B0 magnet for this system using a novel optimization approach and compute simulated B0 maps using 3 magnet modeling approaches. In doing so, we demonstrate the feasibility of realizing an acceptably-uniform whole-brain MRI magnet with mean B0 of 86mT and weighing under 25kg.

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An Irregular Aubert Ring-Pair-Aggregate Optimized with Improved Gradient for Head Imaging in a Low-field Portable MRI System
Zhi Hua Ren1, Jia Gong1, and Shao Ying Huang1

1Singapore University of Technology and Design, Singapore, Singapore

We present a design and optimization of an irregular Aubert ring-pair-aggregate permanent magnet array that generates 2D B0-field with an improved gradient for head imaging for a low-field portable MRI system. The ring-aggregates are discretized into fan-shaped sections with identical angles and varying outer diameters for design and optimization. Genetic algorithm (GA) was used. Compared to a Halbach-array, the proposed array shows an increased in field strength (111.2 mT) with a controlled inhomogeneity, and an enhanced gradient (off-center-concentric-pattern). It leads to better reconstructed images using simulations where the central blurring area is eliminated.

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Single H-Bridge Shimming Driver
Huijun Yu1, Sebastian Littin1, Feng Jia1, Stefan Kroboth1, and Maxim Zaitsev1

1Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany

The multi-channel shimming coils have been proposed to improve the magnetic field homogeneity locally. The one-coil-one-driver solution is preferred to keep the high flexibility. The linear-mode and switch-mode solutions are feasible for such low current applications. However, the switch-mode current driver has the advantage of smaller size in space-limited situations, such as for coils with high number elements. Here we present the design and implementation of a single H-bridge shimming driver. The performance comparison of analog controller and digital controller is shown, and also two different pulse width modulation methods.

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A cryogen-free actively shielded HTS magnet for a 1.5 T MRI system
Yi Li1, Steffen Lother1, Andreas Voß2, Robert Odenbach1, Leander Bartsch2, and Stefan Röll1

1Neoscan Solutions GmbH, Magdeburg, Germany, 2Institute for Medical Engineering, Otto-von-Guericke University, Magdeburg, Saxony-Anhalt, Germany, Magdeburg, Germany

A cryogen free actively shielded magnet for 1.5 T MRI is being developed. High temperature superconductor is used for the fabrication of the magnet. We bring this first prototype for neonatal MRI system which requires more compact dimension and tighter stray field of the magnet. Magnet design has been finished and one coil of the total seven coils has been built and tested. The experimental results are satisfactory in terms of cooling performance, joint resistance and magnetic field. It successfully approves the feasibility of the concept and more results will be shown when the conference starts.

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Designs of shim coils with distributed currents for 3T human brain magnetic resonance imaging
Mustafa Kaan Çan1, Pei-Yan Li2, Jiazheng Zhou2,3,4, Pu-Yeh Wu2, Yi-Tien Li2, Risto Ilmoniemi1, and Fa-Hsuan Lin1,2,5

1Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland, 2Institute of Biomedical Engineering, National Taiwan University, Taipei City, Taiwan, 3High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 4Graduate Training Center of Neuroscience, IMPRS, University of Tübingen, Tübingen, Germany, 5Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada

We propose single-channel head shim coils with either a helmet or a cylinder geometry. Shim current paths were designed by the stream function method with a realistic target field from a group of human subjects (n = 31). A smoothness constraint was included to decrease shim coil complexity. Helmet and cylinder shim coils with shim current amplitudes 4.2 and 6.9 A improved the standard deviation of residual magnetic field by approximately 17%, respectively.

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High-resolution numerical simulation of respiration-induced dynamic B0 shift in the head in high-field MRI
So-Hee Lee1,2, Ji-Seong Barg1,2, Seok-Jin Yeo1,2, and Seung-Kyun Lee1,2

1Department of Biomedical Engineering, Sungkyunkwan university, Suwon, Korea, Republic of, 2Center for Neuroscience Imaging Research, IBS, Suwon, Korea, Republic of

To investigate B0 fluctuation in the head induced by respiration in high field MRI, we simulated respiration with a human 4D phantom model, and calculated B0 in the brain by an efficient calculation algorithm. Simulated B0 was analyzed for the spatiotemporal distribution and voxel size dependence. The amplitude of dynamic B0 change exhibited strong inferior/superior gradient and significant anterior/posterior gradient, consistent with previous experimental data. Compared to the previous modeling studies, our simulation can yield more reliable, high-resolution results within a relatively short calculation time.

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Dynamically Updated B0 Shimming for Multi-band Imaging with High Order Spherical Harmonics
Hoby Hetherington1, Chan Moon1, and Jullie Pan1

1Radiology, University of Pittsburgh, Pittsburgh, PA, United States

High order spherical harmonic shims (SH) and multi-coil approaches have demonstrated that the best B0 homogeneity  for 2D human brain imaging is achieved by dynamic updating and single slice-by-slice (SBS) shimming. However, the use of multi-band (MB) imaging with its superior data collection efficiency has overshadowed the benefits of single SBS updating. In this abstract we demonstrate that MB=2 B0 shimming (MBB0) can be achieved with equivalent homogeneity as single SBS imaging for SH shimming with a 4th+ high order/degree shim insert. For MBB0 =3 or 4, significant gains over static 4th order shimming are predicted.

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Permanent magnet based 3D spatial encoding for Ultra-Low field MRI
Michael W. Vogel1, Ruben Pellicer-Guridi1, Jiasheng Su1, Viktor Vegh1, and David C. Reutens1

1Centre for advanced imaging, University of Queensland, Brisbane, Australia

We explore the use of small permanent magnets moving along prescribed helical paths for spatial encoding in ultra-low field magnetic resonance systems based on Halbach arrays. A semi-analytical simulation method was developed to analyse different magnet path and orientations. For proof-of-concept, different helical magnet paths and lengths for one and two small magnets were considered to establish spatial encoding efficiency. We demonstrate that a single small encoding magnet moving around the sample in a single helical revolution can be used to generate 3D images via the method of back projection for image reconstruction.

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Design of a shimming coil matched to the human brain anatomy
Feng Jia1, Hatem Elshatlawy1, Ali Aghaeifar2, Sebastian Littin1, Stefan Kroboth1, Ying-Hua Chu1, Yi-Cheng Hsu1, Xiang Gao1, Huijun Yu1, Philipp Amrein1, Wenchao Yang1, Jiazheng Zhou2, Pierre Levan1, Klaus Scheffler2,3, and Maxim Zaitsev1

1Dept. of Radiology · Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 3Department of Biomedical Magnetic Resonance, University of Tuebingen, Tuebingen, Germany

We propose a novel design method of a shim coil specially optimized for the human brain. Numerical results demonstrate the validity of the method. The resulting coil layouts can pave a way towards a novel shimming coil specifically intended for human brain shimming. The proposed design method can be extended to other applications and organs.

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The Dipole Boundary Method : a simple approach to compute stream functions for shim coil design
Bruno Pinho Meneses1,2 and Alexis Amadon1

1Neurospin/CEA-Saclay, Gif-sur-Yvette, France, 2Université Paris-Saclay, Orsay, France

A simple and easy to implement method for shim coil design is proposed as an alternative to most popular, but complicated methods. It is straightforward in obtaining the optimal stream function, which is further discretized into a coil wiring, using an analogy to magnetized material and a boundary discretization into square dipoles. Simulation results show good performance in designing spherical harmonics shim coils.

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Optimized multi-coil array design for human brain shimming at Ultra-High Field
Bruno Pinho Meneses1,2, Michel Luong3, and Alexis Amadon1

1Neurospin/CEA-Saclay, Gif-sur-Yvette, France, 2Université Paris-Saclay, Orsay, France, 3IRFU/CEA-Saclay, Gif-sur-Yvette, France

A numerical method based on stream function Singular Value Decomposition is proposed for optimization of Multi-Coil array (MCA) design for human brain shimming. It provides geometries other than circles for shim loops and halves the amount of channels needed to achieve the same whole-brain inhomogeneity reduction as current MCA systems.  Strong impacts are expected for imaging and spectroscopy at Ultra-High Field.

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Passive shimming for a Portable Head-Only scanner
Mark Hunter1, Konstantinos Bouloukakis1, Sebastian Theilenberg2, Naoharu Kobayashi3, Christoph Juchem2,4, and Ben J Parkinson1

1Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Lower Hutt, New Zealand, 2Department of Biomedical Engineering, Columbia University in the City of New York, New York, NY, United States, 3Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 4Department of Radiology, Columbia University in the City of New York, New York, NY, United States

Part of a collaboration under NIH grant U01EB025153 is leading to the development of a highly compact brain imaging scanner.  In order to realize the required B0 uniformity of the scanner, we have developed passive shimming techniques that will be robust despite a low field uniformity and non-cylindrical magnet warm bore layout.  This presentation describes the methods and results we will use to shim our compact scanner.

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Superconducting shim coil design using a quasi-saddle geometry
Yaohui Wang1, Qiuliang Wang1,2, Lei Guo3, Zhifeng Chen4, Zhongbiao Xu4, Hongyi Qu1, and Feng Liu3

1Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China, 2School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China, 3School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, 4School of Biomedical Engineering, Southern Medical University, Guangzhou, China

An improved method was proposed to design superconducting shim coil with smooth rounded corner, which can significantly ease the winding and fabrication, and augment the magnetic field accuracy. A quantitative comparison between the shim coil using the improved strategy and the conventional standard design shows clear advantage.

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Multi-Coil Array for Combined Imaging and B0 Shimming in a Portable Head-Only Scanner
Sebastian Theilenberg1, Yun Shang1, Naoharu Kobayashi2, Ben J. Parkinson3, and Christoph Juchem1,4

1Department of Biomedical Engineering, Columbia University in the City of New York, New York, NY, United States, 2Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 3Robinson Research Institute, Victoria University of Wellington, Wellington, New Zealand, 4Department of Radiology, Columbia University in the City of New York, New York, NY, United States

To improve accessibility of MRI and to enable advanced studies on motor coordination, we are part of the U01EB025153 collaboration to develop a compact 1.5 T head-only scanner enabling free limb movement. The compact size of the magnet significantly increases B0 inhomogeneity, necessitating the use of novel imaging concepts robust to B0 inhomogeneities that in turn require advanced B0 field modeling capabilities. Here, we introduce a 31-coil Multi-Coil (MC) design capable to generate linear and non-linear MR image encoding fields as well as complex B0 shim fields with low space and power requirements.

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Preliminary Design Exploration for a Head and Neck Gradient Coil: Effect of Shoulder Cut-out Length on Performance
Eric J Lessard1, William B Handler1, and Blaine A Chronik1

1The xMR Labs, Department of Physics, Western University, London, ON, Canada

A preliminary design study on a shoulder cut-out head and neck gradient coil for improved imaging of the neck was performed.  The designs presented here allow a shifted imaging region such that the neck and cervical spine can be placed directly in the imaging region. This work represents the first step in a larger design study and work is still ongoing to determine the effect on gradient coil performance as design parameters are modified. Ultimately, this will allow high performance imaging of both the head and neck.

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Overlapped Monolithic Transmission Line Resonator Receiver and B0 Shim Array For Functional Imaging of the Human Temporal Lobe
Alexander Bratch1, Jerahmie Radder2, Parker Jenkins3, Steve Jungst2, Gregory Metzger2, Kamil Ugurbil2, and Gregor Adriany2

1CMRR, Biomedical Engineering, Psychology, University of Minnesota, Minneapolis, MN, United States, 2CMRR, University of Minnesota, Minneapolis, MN, United States, 3Marquette University, Milwaukee, WI, United States

Transmission Line Resonator (TLR) coils have been employed and evaluated as simultaneous RF Tx/Rx and B0 shimming elements. However, overlapped variants of these designs which target specific brain regions have yet to be attempted. Here, we have developed an overlapped TLR Rx/B0 shimming array targeted for imaging the temporal lobe at 7T. Bench testing and simulation results demonstrate the feasibility and benefits of an overlapped TLR Rx/B0 shimming array for targeted imaging of targeted brain structures.

1483
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A novel few-channel coil design for human brain shimming based on stream function Singular Value Decomposition
Bruno Pinho Meneses1,2 and Alexis Amadon1

1Neurospin/CEA-Saclay, Gif-sur-Yvette, France, 2Université Paris-Saclay, Orsay, France

A method for whole-brain shim coil design for Ultra-High field is proposed using Singular Value Decomposition of tailored stream functions to create a small set of independently driven coils providing the same performance as shim inserts with numerous high-order spherical harmonics coils.


RF Coils & Arrays

Exhibition Hall
Monday 9:15 - 10:15
 Engineering

1484
Computer 51
Dipole antenna for rat spinal cord imaging at ultra-high field
Ting Yin1, Ileana Ozana Jelescu1, Rolf Gruetter1, and Özlem Ipek1,2

1CIBM-AIT, École polytechnique fédérale de Lausanne, Lausanne, Switzerland, 2Department of Biomedical Engineering, King’s College London, London, United Kingdom

Dipole antenna designs were introduced to pre-clinical spinal cord imaging at ultra-high field. The tuning and matching circuit can be adapted to both 9.4 T and 14.1 T magnet with simple adjustment. Dipole antennas provided good longitudinal coverage for the animal, and optimal penetration for spinal cord imaging. In terms of transmit efficiency and field homogeneity over rat spinal cord, dipole antenna design is a flexible and promising candidate for ultra-high field imaging.

1485
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Attachable B0-shim Array: An Add-on for RF Coils
Yang Gao1, Yi Sun2, and Xiaotong Zhang1

1Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, 2MR Collaboration Northeast Asia, Siemens Healthcare, Hangzhou, China

In the present study, as an add-on to commercial-available RF coils, a novel B0-shim coil design for local B0 shimming was proposed, based on which 8-channel B0-shim array has been designed to attach to Nova 1Tx/32Rx head coil for local B0 shimming at 7T. With minor interference to RF coil, the apparent improvement in local B0 shimming has been demonstrated by using the proposed attachable B0-shim array. The present setup offers a feasible and promising means for practical higher-order local B0 shimming technology. It is believed that the proposed approach could potentially merit a broad scope of researches such as clinical diagnosis and cognitive neuroscience.

1486
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A 32-channel transmit/receive radiofrequency head coil for 7T UHF MR
Stefan HG Rietsch1,2, Stephan Orzada1, Sascha Brunheim1,2, Andreas K Bitz3,4, Maximilian N Voelker1,2, Viktor Pfaffenrot1,2, Marcel Gratz1,2, Daniel Leinweber1, Jonathan Weine1, Sarah Handtke1, Oliver Kraff1, Mark E Ladd1,3,5, Peter Koopmans1,2, and Harald H Quick1,2

1Erwin L. Hahn Institute for MR Imaging, University of Duisburg-Essen, Essen, Germany, 2High-Field and Hybrid MR Imaging, University of Duisburg-Essen, Essen, Germany, 3Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Electromagnetic Theory and Applied Mathematics, Faculty of Electrical Engineering and Information Technology, University of Applied Sciences Aachen, Aachen, Germany, 5Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany

In this work, a 32-channel transmit/receive (32Tx32Rx) head coil for 7T UHF MRI was developed and evaluated. The performance of this coil is compared to a commercially available 1Tx32Rx head coil regarding noise correlation, signal-to-noise ratio (SNR) and B1 homogeneity. The results indicate that high flexibility concerning RF shimming is provided by the 32Tx32Rx head coil that translates into a more homogeneous flip angle distribution compared to the 1Tx32Rx head coil. First 7T MR imaging results show the increased coverage of both the head and superior parts of the neck.

1487
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High-Q, tunable High Temperature Superconducting receiver coil for 13C applications
Rafael A. Baron1, Juan D. Sanchez-Heredia1, Daniel Højrup Johansen1, Vitaliy Zhurbenko1, and Jan H. Ardenkjær-Larsen1

1Technical University of Denmark, Kgs. Lyngby, Denmark

Dissolution DNP has emerged as a technique to improve SNR in an NMR experiment with inherent limitation of polarization retention in solution ranging, in general, from 30 to 100 s for the interesting bio-molecules. The limitation in sensitivity and available time window can be, however, improved by a better SNR of the RF receivers. At 3 T the Larmor frequency of the 13C nuclei is 32.13 MHz, which is still in the electronics noise dominated regime for smaller coils. A High-Temperature Superconducting (HTS) receiver coil with high-Q, remotely tunable, detunable and compatible to standard electronics Tin soldering has been developed for MRI 13C applications.

1488
Computer 55
MR vessel wall imaging of intracranial and carotid arteries with a 40-channel coil system at 3 T
Qiaoyan Chen1, Zidong Wei2, Lei Zhang1, Changjun Tie1, Qiang He2, 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, 2Shanghai United Imaging Healthcare, Shanghai, 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

     Due to the small cross-sectional size of the vessel wall and the cord, and susceptibility effects, especially in the carotid and the spinal cord, MR vessel wall imaging of intracranial and carotid arteries still remains challenging. In this work, a 40-channel coil system that consists of a 32-channel head coil combined with an 8-channel carotid coil was implemented and characterized in its performance by comparison with a 24-channel head and neck joint coil. As a result, the proposed 40-channel coil system provides improved performance in SNR, parallel imaging capability, and image quality.

1489
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A 4-Channel iPRES-W AIR Coil Array for Simultaneous MR image Acquisition and Wirelessly-Controlled Localized B0 Shimming of the Spinal Cord
Jonathan D. Cuthbertson1,2, Dean Darnell1,2, Robert Stormont3, Fraser Robb3, Allen W. Song1,2, and Trong-Kha Truong1,2

1Brain Imaging Analysis Center, Duke University, Durham, NC, United States, 2Medical Physics Graduate Program, Duke University, Durham, NC, United States, 3GE Healthcare, Aurora, OH, United States

B0 inhomogeneities near air-tissue interfaces can cause distortions, signal loss, and incomplete fat suppression in many applications such as diffusion-weighted imaging of the spinal cord. Here, we develop a 4-channel iPRES-W AIR coil array to perform simultaneous imaging and wirelessly-controlled localized B0 shimming of the cervical spinal cord. In vivo experiments showed a 58.5% reduction in B0 root-mean-square-error (RMSE) after shimming the spinal cord using the iPRES-W AIR coil array, resulting in substantially reduced geometric distortions in diffusion-weighted images, ADC maps, and FA maps

1490
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Stretchable and Flexible Conductive-Thread Based Radiofrequency Coils for Magnetic Resonance Imaging
Jana Vincent1,2 and Joseph Rispoli1,3

1Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 2Basic Medical Sciences, Purdue University, West Lafayette, IN, United States, 3School of Electrical & Computer Engineering, Purdue University, West Lafayette, IN, United States

An omnidirectional stretchable and flexible radiofrequency coil has been developed using conductive thread stitched onto athletic material.  This single-loop surface coil can be placed at the closest proximity to the skin.  When compared to a flexible, copper-clad printed circuit board coil, resulting MR FSE images of a muscle phantom showed comparable SNR and image quality, especially when compared to a PCB coil spaced 4.2 cm above the phantom. This design allows not only for close proximity of placement to the skin, but also for joint imaging at various degrees of flexion and positioning.

1491
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Enhancement of transmit and receive efficiencies with hybridized meta-atom in 7T head coil
Marc Dubois1, Lisa Leroi2, Zo Raolison2, Redha Abdeddaim1, Tryfon Antonakakis3, Julien De Rosny4, Alexandre Vignaud2, Pierre Sabouroux1, Elodie Georget2, Benoit Larrat2, Gérard Tayeb1, Nicolas Bonod1, Alexis Amadon2, Franck Mauconduit5, Cyril Poupon2, Denis Le Bihan2, and Stefan Enoch1

1Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France, 2CEA, DRF, JOLIOT, NeuroSpin, UNIRS, Université Paris-Saclay, Gif sur Yvette, France, 3Multiwave Technologies AG, Geneva, Switzerland, 4ESPCI Paris, PSL Research University, CNRS, Institut Langevin, Paris, France, 5Siemens Healthineers, Saint Denis, France

We show that hybridized meta-atom can be used to improve transmit and receive operation in a 7T head birdcage coil equipped with a 32-channel receive array. Our results demonstrates the enhancement of both transmit and receive signal with the possibility to fill one of the gap usually observed in the brain temporal lobes. This metamaterial based passive shimming strategy provides a cost effective, long-lasting, and non-toxic solution without any impact on the patient’s comfort during the examination.

1492
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Minimally invasive implantable NMR microcoil for in vivo MRS and MRI in submicroliter volumes
Yannick Crémillieux1, Noël Pinaud1, Benadjem Felouah1, Vi Thi Thuy Pham1, and Alan Wong2

1Institut des Sciences Moléculaires, CNRS, Université de Bordeaux, Bordeaux, France, 2NIMBE, CEA Saclay, Gif-sur-Yvette, France

Due to sensitivity and invasiveness issues, the use of implanted NMR microprobes remains a poorly explored field of research, with no emerging or significant biomedical applications.  In this study, we report the realization, characterization and applicaiton of an innovative design for implantable microprobe allowing a drastic minimization of the probe invasiveness. The results obtained in vitro and in vivo demonstrate the potential of this microprobe architecture for MRS and MRI investigation of organs and tissues in submicroliter volumes.

1493
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Universal Coils: Multisubject Optimization of 8-Channel Many-Element Parallel Transmit Arrays
William Allyn Grissom1, Xinqiang Yan1, and Zhipeng Cao1

1Vanderbilt University, Nashville, TN, United States

A large number of coils is desirable in parallel transmission to achieve uniform excitation while controlling SAR in a subject-adaptive manner, but only a small number of transmit channels are available on most ultra-high field scanners. We describe an algorithm that optimally groups a large number of coils into a small number of channels, based on the fact that if two coils are in the same channel, the matrix formed by collecting their slice-by-slice RF shims will have rank one. The algorithm was used to optimize the coil-to-channel mappings of a 30-coil array at 7T, based on 8 representative heads.

1494
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A 48-Channel ex vivo Brain Array Coil for Diffusion-Weighted MRI at 3T
Alina Scholz1, Markus May1, Robin Etzel1, Mirsad Mahmutovic1, Nicolas Kutscha1, Lawrence L Wald2, Anastasia Yendiki2, and Boris Keil1

1Institute of Medical Physics and Radiation Protection, Mittelhessen University of Applied Sciences, Giessen, Germany, 2A.A. Martinos Center for Biomedical Imaging, Dept of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA, Boston, MA, United States

In diffusion weighted MRI in vivo spatial and angular resolution is often limited to the macroscale regime, due to the maximum examination time that is appropriate for human subjects. Ex-vivo DWI of fixed tissue can overcome this limitation by providing large acquisition times. Therefore, a 48-channel ex-vivo brain array receive coil was developed to be used with the 3T Connectome diffusion scanner. The coil was characterized with both bench and image metrics and compared to a 64ch whole head coil. The size-optimized 48-channel array coil provides increased reception sensitivity and is well-suited for high resolution ex-vivo MRI studies.

1495
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Towards uncompromised merging of 1H and 31P receive arrays for multi nuclear metabolic imaging in the brain at 7T
Ines Chavarria1,2, Dimitri Welting1, Marco Fantasia1, Quincy van Houtum1, Jannie Wijnen1, Dennis W.J. Klomp1, and Bart R. Steensma1

1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, 2University of Twente, Enschede, Netherlands

In order to optimally integrate 31P MRS and 1H MRI, a 1H birdcage coil is combined with a 16 channel dual-tuned 31P/1H receive loop array for 7T, inserted in a 31P bodycoil. 1H performance was compared to the existent NOVA head coil. Similar SAR levels and B1+ distributions were obtained, but the SNR decreased in the unshielded birdcage. SNR results might be improved upon by detuning the unshielded birdcage coil during receive mode, yet the 31P MRSI results show very high SNR. It is concluded that the unshielded birdcage coil has an adequate 1H transmit performance and has the potential for accelerated imaging with the 16 double-tuned receive loops. 

1496
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Real-time image-based tracking of B0 shim elements in flexible matrix shim arrays for dynamic B0 shimming of the abdomen
Bernhard Gruber1,2, Jason Stockmann1, Bastien Guerin1, and Lawrence L Wald1

1Department of Radiology, MR Physics & Instrumentation Group, A.A. Martinos Center for Biomedical Imaging, MGH, Harvard Medical School, Charlestown, MA, United States, 2Division MR Physics, Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria

High-order matrix shimming has proved useful for addressing B0 susceptibility issues but requires prior knowledge of the shim elements position. For rigid coil formers the shim loops are fixed in space and the field maps can be pre-measured in a phantom. Flexible or movable arrays used in abdominal imaging present a challenge since the element position is patient-specific. Here we introduce a marker system for rapidly detecting the element position prior to or during matrix shimming.  Our tests show we can successful determine loop position to accurately generate B0 field maps in good agreement with experimentally measured maps.

1497
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A PET COMPATIBLE 17O/1H COIL FOR SIMULTANEOUS MULTINUCLEAR PET/MR
Karthik Lakshmanan1, Seena Dehkharghani1, Guillaume Madelin1, and Ryan Brown1

1Department of Radiology, New York University Langone Health, Newyork, NY, United States

Direct MR oximetry by imaging 17O isotope can be a viable alternative over the conventionally used 15O PET tracer. In this work we developed a dual-tuned 17O/1H coil array with potential PET compatibility to explore brain oximetry and support simultaneous PET tracers to provide complementary insights into brain function.

1498
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Improved B1+ efficiency of a dipole antenna equipped with high dielectric constant (HDC) materials at 10.5T
Myung Kyun Woo1, Lance DelaBarre1, Russell Lagore1, Steve Jungst1, Qing Yang2, Bei Zhang3, Sebastian Rupprecht2, Riccardo Lattanzi3, Mike Lanagan2, Maryam Sarkarat2, Kamil Ugurbil1, and Gregor Adriany1

1Center for Magnetic Resonance Research, Minneapolis, MN, United States, 2Pennsylvania State University, Hershey, PA, United States, 3Center for Biomedical Imaging, New York, NY, United States

We evaluated the performance of 10.5T RF coils composed of dipole antennas and high dielectric constant (HDC) ceramic materials placed in close proximity to the dipole antenna. We investigated the impact of the location of the HDC material relative to the dipole antenna. Both simulations and experimental verification indicate that a counterintuitive “Flipped” geometry positioning the dipole between the HDC material and the sample shows notable improvement in terms of the B1+ efficiency. We suggest further exploration of this new setup for ultra-high field (UHF) transmit arrays.   

1499
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Prototype investigation for a size adaptable RF receiver coil capable of various body parts and sizes
Kohjiro Iwasawa1, Yosuke Otake1, Hideta Habara2, Kazuyuki Kato2, and Hisaaki Ochi1

1Research & Development Group, Hitachi Ltd., Tokyo, Japan, 2Healthcare Business Unit, Hitachi Ltd., Tokyo, Japan

A size-adaptable RF receiver coil prototype which can displace inter-element distance with negligible SNR degradation was investigated. We applied a simple method to enhance blocking impedance of the preamp decoupling circuit by using intentionally small matching capacitance. SNR of the size-adaptable prototype was evaluated for phantoms of 5 sizes ranging from knee size to abdomen size against commercial coils dedicated for each body parts. Despite of its broad size adaptability across various body parts and sizes, the prototype showed higher SNR than each commercial coil.

1500
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Development and Test of an Optimized  8TX/16RX  Array for Ultra-High Resolution Ex-Vivo Myocardial Tissue Characterization with 7T MRI  :   Initial Experience  and Quality Assessment.
Maxim Terekhov1, Ibrahim A. Elabyad1, David Lohr1, Maria R. Stefanescu1, and Laura Maria Schreiber1

1Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center, University Hospital Wuerzburg, Wuerzburg, Germany

The MRI measurements of the excised hearts providing stable “ground truth” high resolution images are important part of cardiac MRI at ultra-high field. We report the initial results of testing an in-house developed multiple element transceiver array (mTA) with parallel transmit support optimized for submillimeter spatial resolution ex-vivo heart tissue characterization MRI at 7T. The array testing included SNR, B1-shimming, g-factor, T2* and DTI mapping with high parallel imaging acceleration factors.  The designed 8TX/16RX array demonstrated high efficiency of both TX and RX properties for (ultra)high ex-vivo myocardial tissue characterization imaging at 7T with essential superiority to a commercial 1TX/32RX coil.  

1501
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WEARABLE AND STRETCHABLE SURFACE BREAST COIL
Busra Kahraman Agir1, Basak Bayrambas2, Korkut Yegin3, and Esin Ozturk Isik2

1Industrial PhD Program in Advanced Biomedical Technologies, Dokuz Eylul University, Izmir, Turkey, 2Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey, 3Department of Electrical and Electronics Engineering, Ege University, Izmir, Turkey

A novel wearable and stretchable single loop breast coil made from conductive thread is introduced with a coil geometry which can expand and retract in accordance with the breast while preserving good quality factor. Images of both the small phantom and the medium phantom could be acquired by S-M coil. Similarly, M-L breast coil was used to obtain the images of both the medium phantom and the large phantom. Highest SNR was obtained when small phantom was imaged using S-M coil and the lowest SNR was obtained with large phantom when it was imaged using M-L coil.

1502
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Application of an RF Current Mirror for MRI Transmit Coils
Roland Müller1, Tobias Lenich1, Evgeniya Kirilina1, and Harald E. Möller1

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

Some types of MRI transmit coils (e.g. Helmholtz coils) require equal currents in different coil elements. We present a novel feeding concept based on a passive RF current mirror, which ensures equal currents even if the loading and tuning of individual elements differ. Analytical equations are given for the dimensioning. It is demonstrated by simulations and experiments that the concept is viable, especially for ultra-high field imaging.

1503
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1H-23Na Dual-Tuned Radio-Frequency volume coil design for MRI at 7 T
Francesca Maggiorelli1,2,3, Alessandra Retico2, Eddy Boskamp4, Fraser Robb5, Angelo Galante6, Marco Fantasia6, Marcello Alecci6, Gianluigi Tiberi3, and Michela Tosetti3

1Physical Sciences, Earth and Environment, University of Siena, Siena, Italy, 2Pisa Division, INFN, Pisa, Italy, 3IRCCS Stella Maris, Imago7 Foundation, Pisa, Italy, 4Hyperfine Research inc, Guilford, CT, United States, 5GE Healthcare, Aurora, OH, United States, 6Life, Health & Environmental Sciences, University of L’Aquila, L'Aquila, Italy

We present a systematic comparison between two dual-tuned (DT) RF coil models through electromagnetic simulations. The first model (imbricated) consists of two concentrically placed birdcages, whereas the second model (four-rings) consists of two High-Pass birdcage-like structures nested over an internal Low-Pass birdcage. For both DT-RF coil models, the dimensional parameters have been varied in order to optimize the B1+ field homogeneity and the coil efficiency at the proton (298.03MHz) and sodium (78.86MHz) Larmor frequency at 7T. Results show that the longest four-rings DT-RF coil model has the best performances.

1504
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A radiolucent and flexible high impedance coil array to improve the imaging performance of a 1.5T MR-linac
Stefan E. Zijlema1, Luca van Dijk1, Jan J.W. Lagendijk1, Rob H.N. Tijssen1, and Cornelis A.T. van den Berg1

1Radiotherapy, UMC Utrecht, Utrecht, Netherlands

High impedance coils (HICs) are interesting for use in dense receive arrays for the MR-linac, as they lack lumped elements that attenuate radiation. Furthermore, HICs are flexible and exhibit low channel coupling, simplifying high-density array development.  

We compared the performance of a 20-channel prototype setup with the current clinical array and investigated its dosimetric feasibility.

The prototype showed higher SNR values and lower g-factors, thus allowing for higher acceleration factors and faster imaging. Dosimetrically, no clinically significant attenuation was found (<1.5%).

In conclusion, flexible HIC based arrays are highly suitable to construct high density arrays for MRI-guided radiotherapy applications.


1505
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Design and Evaluation of a Novel 8Tx/16Rx Symmetric Coil Array for Cardiac MRI in Large Animals (Pigs) at 7T: Investigation of Decoupling Using a Common Central Ring
Ibrahim A. Elabyad1, M. Terekhov1, M. R. Stefanescu1, D. Lohr1, M. Fischer1, and L. M. Schreiber1

1Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany

A dedicated 8Tx/16Rx coil array was designed and tested for cardiac magnetic resonance imaging (cMRI) ex-vivo pigs at 7T. The cardiac array is composed of 16-elements with physically independent anterior and posterior parts. The anterior array is composed of 8-elements and resembles a symmetric circular shape coil. The central four-elements are decoupled using a common central ring and shared decoupling capacitors. The posterior array was built using 4×2 rectangular symmetric elements configuration. Ex-vivo high-resolution cardiac images were acquired with 0.3 mm x 0.3 mm in plane resolution. The dedicated coil enhances the SNR within the heart by about four-times compared to a commercial human coil.

1506
Computer 73
A low SAR eight element passively fed meander dipole array for 7T prostate imaging
Irena Zivkovic1, Catalina Arteaga de Castro2, and Andrew Webb1

1Radiology Department, C.J. Gorter Center for High Field MRI, Leiden, Netherlands, 2Imaging Division, University Medical Center Utrecht, Utrecht, Netherlands

The purpose is to compare the performance of an eight element passively fed meander dipole antenna designed for body MRI  at 7 Tesla with that of a conventional actively fed array. The measured mean transmit efficiency (B1+/square root input power) in the prostate was 15% lower with the  passively fed dipoles array, but the simulated max SAR10g was 44% lower, meaning that the overall SAR efficiency of the passively fed array is higher. In vivo  RF shimmed turbo spin echo images showed similar image quality for both arrays, but with lower SAR values for the passively fed array. 



1507
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Optimization of RF system for homogenous, consistent, and safe neuro imaging at 7T MRI
Tales Santini1, Sossena Wood1, Tiago Martins1, Nadim Farhat1, Salem Alkhateeb1, Howard J. Aizenstein1, and Tamer S. Ibrahim1

1University of Pittsburgh, Pittsburgh, PA, United States

This work presents two shimming cases for homogenous B1+ at 7T. The Tic-Tac-Toe system was optimized using FDTD simulations and experimentally verified. In the homogenous shim case, the array was capable of delivering a homogeneity of 16.6% (measured) with a SAR efficiency of 1.40μT/√(W/kg) (simulated). In the B1+ efficient shim case, a measured homogeneity of 18.0% and SAR efficiency of 1.55μT/√(W/kg) (simulated) was obtained.  The B1+ field was measured over the whole head above and including the cerebellum and excluding the nasal cavities. The coil performance was compared with the TEM coil and experimentally verified with TSE and T2-SPACE sequences.

1508
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On the SNR of Cryogenic Receive Coils when using Room Temperature Preamplifiers
Daniel Højrup Johansen1, Juan Diego Sanchez-Heredia1, Vitaliy Zhurbenko1, and Jan Henrik Ardenkjær-Larsen1,2

1Technical University of Denmark, Kgs. Lyngby, Denmark, 2General Electric, Brøndby, Denmark

Significant increase of the signal-to-noise ratio (SNR) is possible by cooling receive coils to cryogenic temperatures, if they are not highly sample noise dominated. Conventionally, the noise of the preamplifier is excluded leading to an overestimation of the achievable SNR gain. In this work, we show that for the case of a small-animal birdcage coil for 13C at 3T cooled with liquid nitrogen to 77K, the SNR is overestimated by approximately 40% if the effect of the room temperature preamplifier is excluded. Hence, the preamplifier should either be included in the SNR gain estimation or cooled with the coil.


RF: Other

Exhibition Hall
Monday 9:15 - 10:15
 Engineering

1509
Computer 76
Evaluating 8-independent channel shimming strategies to drive a 16-channel loop-dipole transceiver body imaging array at 7.0 Tesla
M. Arcan Erturk1,2 and Gregory J. Metzger1

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Restorative Therapies Group, Medtronic, Minneapolis, MN, United States

Majority of the installed 7.0T systems have 8-independent transmit channels, therefore additional hardware changes are necessary to fully utilize higher channel count transceiver arrays (i.e. 16-channel loop-dipole body imaging array, 16LD). Here, we investigated three different 8-independent channel phase shimming strategies to drive 16LD and compared against fully independent 16-channel phase-only shimming. 8-independent channel shimming while transmitting power from all 16 array-elements with pre-determined phase difference between loop and dipole elements on the same block causes only about 10% drop in B1+ efficiency compared to 16-independent channel transmit.

1510
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Development of a 16 channel rotated double row transceiver array for neuroimaging at 7T
Nick de Jong1, Wyger M. Brink1, Thomas Ruytenberg1, Thomas P.A. O'Reilly1, and Andrew Webb1

1LUMC, Leiden, Netherlands

A 16 channel rotated double row transceiver array for imaging the human brain at 7T was designed using the recently developed induced current elimination decoupling method. The transmit and receive performance of the coil was characterized by in vivo measurements and compared to a commonly-used commercial two-channel transmit coil.

1511
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B1 performance when excluding RF shields from transmit head coils to simplify multi nuclei and gradient insert setups
D. Welting1, I. Chavarria Marques1, M. Fantasia1, Q. van Houtum1, B.R. Steensma1, E. Versteeg1, J.P. Wijnen1, and D.W.J. Klomp1

1Radiology, University Medical Center Utrecht, Utrecht, Netherlands

RF shielding in MRI is used to enhance B1 efficiency of RF coils by reducing radiation losses and prevent coupling to surrounding materials like the gradient coil (1). However, RF shielding can also complicate the design of RF coils, particularly when used in multi-model setups, like for multi-nuclei experiments or when combined with gradient inserts. Here we demonstrate that the closely fitted RF shield of a head-coil can be removed to use the RF shield inside the bore liner of the MRI system in order to maintain high B1 efficiency.

1512
Computer 79
A multi-function digital receiver for real-time data correction in MRI
Limin Li1 and Alice M. Wyrwicz1,2

1Center for Basic MR Research, NorthShore University HealthSystem, Evanston, IL, United States, 2Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States

We report the early development of an integrated receiver built on a Field Programmable Gate Array (FPGA). The receiver offers the functionalities of combining data acquisition, field sensing, real-time data correction and image reconstruction. We describe the design and implementation of the receiver and demonstrate its capabilities of image acquisition and reconstruction with real-time data correction.

1513
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A head transmit-receive array for a high performance gradient insert
Manuela B. Rösler1, Christoph Leussler2, David O. Brunner1, Thomas Schmid1, Markus Weiger1, Franciszek Hennel1, Roger C. Luechinger1, and Klaas P. Pruessmann1

1Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zürich, Switzerland, 2Philips GmbH Innovative Technologies, Hamburg, Germany

Achievable gradient performance scales with decreasing gradient size which awakes interest in tight-fitting gradient coil design and requires space-restricted RF solutions. In this work, an eight-channel transmit-receive array coil for human head with a B1 field distribution preventing aliasing from the unambiguity volume of a high performance gradient insert and assuring a low eddy current capability is presented. In this configuration, acceptable homogeneous excitation and parallel imaging can be performed even despite the limited space for RF components.

1514
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Homogenous 64-channel RF transmit array for brain imaging at 7T, 9.4T, and 10.5T
Tales Santini1, Sossena Wood1, Howard J. Aizenstein1, and Tamer S. Ibrahim1

1University of Pittsburgh, Pittsburgh, PA, United States

In this work, a 64-channel Tic-Tac-Toe (TTT) transmits array is simulated (with a realistic tuning and matching method) for three field strengths. Phase-only RF shimming was performed to access the array performance. In the whole brain excluding the cerebellum, the coefficient of variation (CV)=15.6%/20.9%/25.0%, Max/Min=3.17/6.29/5.84, for an average B1+=7.47/5.34/3.78μT/√kW at 7T/9.4T/10.5T field strengths, respectively. With these shimming cases, the array presented an average SAR=1.67/2.56/2.72 W/kg for 2μT and SAR efficiency=1.55/1.25/1.21μT/√(W/kg) at 7T/9.4T/10.5T, respectively. The peak SAR=5.35/9.49/10.76W/kg for 2μT at 7T/9.4T/10.5T, respectively. The 64-channel TTT array is capable of producing homogenous B1+ and low levels of SAR for UHF human MRI.

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Comparisons for microstrip and CRLH transmission lines array coils at 7T
Daniel Hernandez1, Jeung-Hoon Seo1, and Kyoung-Nam Kim2

1Neuroscience Research Institute, Gachon University, Incheon, Korea, Republic of, 2Department of Biomedical Engineering, Gachon University, Incheon, Korea, Republic of

The use of Composite right/left handed (CRLH) metamaterial based transmission lines (TL) for high frequency applications can improve the magnetic field intensity and uniformity. This can be achieved independent from its physical length, contrary to the traditional microstrip TL. In this work we compare the |B1| and |E|-field of the CRLH TL with a common microstrip TL when used in an array of two elements. Three arrays with different lengths were compared, resulting in better field uniformity for the case of the CRLH TL. 

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Computer 83
Flexible Low-Profile Coil Array Using “Dummy Loads” for Concurrent TMS-fMRI
William Mathieu1 and Reza Farivar2

1Electrical and Computer Engineering, McGill University, Montreal, QC, Canada, 2Ophthalmology, McGill University, Montreal, QC, Canada

A system was designed for concurrent TMS-fMRI, where functional images across the entire brain may be acquired while stimulating areas with TMS. Dummy loads were used to counteract the loading effects of the TMS coil. This system was able to perform functional acquisitions on phantoms and biological media with the TMS coil present.

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Computer 84
Opencage Radiofrequency Coil Inspired by Metamaterials
Anton NIKULIN1, Julien de Rosny1, Benoit Larrat2,3, Kylian Haliot2,3, and Abdelwaheb Ourir1

1ESPCI, Institut Langevin, PSL Research University, Paris, France, 2Direction de la Recherche Fondamentale / Institut Joliot / NeuroSpin, Commissariat à l’Energie Atomique et aux Energies Alternatives, Gif sur Yvette, France, 3Université Paris Saclay, Saclay, France

We propose a volume radiofrequency coil for MRI that provides a lateral access to its inner   volume. This coil, called «opencage», is designed by revisiting birdcage coils as metamaterial transmission line with broken periodicity.  An opencage dedicated for imaging at 7T of the head of small rodents is developed. The design of this opencage is optimized using numerical simulation. Finally in-vivo preclinical imaging of the head of a mouse is presented. We show that the opencage coil efficiency is similar, especially in terms of field homogeneity and SNR as a conventional 8-legs birdcage coil.

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Computer 85
Dependence of Radiofrequency field enhancement on the geometry of the monolithic high dielectric ceramics at 3 T
Jue Hou1, Sebastian Rupprecht1, Christopher Sica1, and Qing Yang1

1Radiology, The Pennsylvania State University College of Medicine, Hershey, PA, United States

Ultra-high dielectric constant (uHDC) materials can effectively manipulate and enhance the RF field. The effects of uHDC materials on RF field is closely related to the geometry of the material in relation to RF coils. The uHDC ceramics with a given geometry can possess intrinsic resonance modes which also depends on its mutual coupling with the coil. In this study, we compared the B1+ field enhancement of rectangular uHDC blocks with different thickness, resonance condition and sizes of coupling coils. Computer modeling and phantom experiments are performed in this study.

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Design Considerations of a 64-Channel Receive / 16-Channel Transmit Coil Array for Head, Neck, and Cervical-Spine Imaging at 7 T
Markus May1, Robin Etzel1, Laleh Golestanirad2, Christina Triantafyllou3, Yulin V. Chang4, Shivraman Giri4, Lawrence L. Wald5, and Boris Keil1

1Institute of Medical Physics and Radiation Protection, Dep. of Life Science Engineering, Mittelhessen University of Applied Science, Giessen, Germany, 2Department of Radiology, Northwestern University, Chicago, IL, United States, 3Siemens Healthineers AG, Erlangen, Germany, 4Siemens Medical Solutions USA, Inc., Boston, MA, United States, 5A.A. Martinos Center for Biomedical Imaging, Dept of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States

A 64chRx/16chTx head-neck-Cspine array coil was constructed and bench tested. A new UHF topology has been introduced, by merging two commonly separated array coil functionalities (Rx, Tx) at ultra-high field MRI into one anatomically shaped close-fitting housing. The ultimate two-folded goal of this study was to increase clinical benefit in ultra-high field neuroimaging through the extension of the brain region to the cervical spine and to decrease patient’s anxiety and discomfort using a patient-friendly coil design.

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A Preclinical Volume Coil with Artificial Magnetic Shield for 7 Tesla MRI
Ksenia Lezhennikova1, Anna Hurshkainen1, Constantin Simovski2, Alexander Raaijmakers3, Irina Melchakova1, Redha Abdeddaim4, and Stanislav Glybovski1

1Faculty of Physics and Engineering, ITMO University, Saint-Petersburg, Russian Federation, 2Department of Electronics and Nanoengineering, Aalto University, Aalto, Finland, 3Department of Radiotherapy, UMC Utrecht, Utrecht, Netherlands, 4Fresnel Institute, Aix-Marseille University, Marseille, France

In this work the artificial magnetic shield structure was proposed aimed to improve the performance of preclinical volume coil for 7 Tesla MRI. Particularly, transmit efficiency as well as receive sensitivity of small-animal bird-cage coil was studied in the presence of both ideal electric and magnetic screen at the first step. Next, practical artificial magnetic shield structure using the principles of operation of high-impedance corrugated surfaces was suggested. B1distribution of the small-animal bird-cage coil equipped with corrugated surface structure was calculated and compared with the reference case of ideal electric screen. Numerical results demonstrated improved transmit efficiency and receive sensitivity of the bird-cage coil with the artificial magnetic shield structure comparing to the reference case. 

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Common Mode Analysis and SNR Performance of a Traditional Loop Coil versus an Integrated Balun Coil
Wolfgang Loew1, Christopher Ireland1, Ronald Pratt1, Randy Giaquinto1, and Charles Dumoulin1

1Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States

Common mode field distributions along a coaxial cable attached to a traditional loop coil and an integrated balun coil were analyzed using electromagnetic simulations. For comparison, an equivalent loop and an integrated balun coil were constructed and common mode voltages were measured along the coaxial cable attached to each coil. SNR performance of both coils was measured and analyzed in a phantom at 3T.

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Multiparameter Analysis Method for B1 Acquisition (MAMBA): A tool for RF coil design and SNR estimation for short T2* samples
Agazi Samuel Tesfai1, Johannes Fischer1, Ali Caglar Oezen1, Ute Ludwig1, and Michael Bock1

1Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany

A software tool (Multiparameter Analysis Method for B1 Acquisition - MAMBA) to design volume coils is presented for short T2* samples that optimizes relative SNR. MAMBA includes relevant RF coil parameters and evaluates performance. Sample and pulse sequence properties such as T2* relaxation times and echo time (TE) are considered. The tool is tested in a comparison of a commercial head coil and an optimized birdcage coil for imaging of an Egyptian mummy head.

1523
Computer 90
Improving RF efficiency in the brain and the neck at 7T using a novel pTx coil
Mohamed Tachrount1, Bleddyn Woodward1, Emre Kopanoglu1, Michel Italiaander2, Denis Klomp2,3, Ian Driver1, and Richard Wise1

1CUBRIC, School of psychology, Cardiff University, Cardiff, United Kingdom, 2MR Coils, Zaltbommel, Netherlands, 3Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands

MRI at UHF is promising for a variety of clinical applications however it is challenging because of B0 and B1 inhomogeneities and SAR limitations. To improve the RF efficiency in the brain and the neck, a novel 8Tx/32Rx RF coil has been built by MR coils. Its performance in terms of B1+ intensity and homogeneity at the brainstem/cerebellum and the neck was assessed and compared with the standard Nova Medical 8Tx/32Rx coil. The novel coil allows for a higher B1+ at the brainstem/cerebellum and the neck where B1+ mapping and shimming need further optimisation for ASL application.

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Full Wave vs Quasistatic Simulation Accuracy at 3 Tesla
Michael Beck1, Dennis Parker1, and Rock Hadley1

1Radiology, University of Utah, Utah Center For Advanced Imaging Research (UCAIR), SALT LAKE CITY, UT, United States

Full wave simulations are known for their high accuracy, but simulation optimization is not feasible with FDTD and FEM for vast numbers of MRI coil applications. Optimization strategies do have feasible runtimes for quasi-static solutions, but the system being simulated must be small compared to the electromagnetic wavelength since they do not account for boundary conditions. This work uses multiple single loop coils of different diameters and three phantoms with a simple geometry to compare the accuracy and usefulness of full wave and quasi-static solutions of RF coils at 3T. Full wave simulations proved to be significantly more accurate.

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A 64-Channel Phased-Array Head Neck Coil for Neurovascular/fMRI at 3T
Haoqin Zhu1, Xiaoyu Yang1, Michael Wyban1, Yiping Guan2, Yoshinori Hamamura2, Yuji Takano3, and Kazuya Okamoto3

1Quality Electrodynamics, LLC (QED), Mayfield Village, OH, United States, 2Canon Medical Research USA, Inc., Mayfield Village, OH, United States, 3Canon Medical Systems Corporation, Kanagawa, Japan

Close-fitting the coil elements along the head and neck is a typical design of higher density phased-array head neck coils in order to provide higher SNR and acceleration. But this limits patient comfort and excludes larger patients. In this work we present a 64-channel head neck coil which can image large patients for neurovascular/fMRI at 3T. The coil test results show superior SNR in imaging compared to both a clinical 32-channel head array coil and 16-channel head neck array coil respectively.

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Computer 93
A 16-Channel Array Coil for Anesthetized Monkey Multi-modal Neuroimaging at 3T
Yang Gao1, Xiaojie Wang2, Robert Friedman2, Mykyta Chernov2, Christopher Kroenke2, 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, 2Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, United States

A 16-channel array coil has been developed in our laboratory for anesthetized monkey brain imaging at 3T, with a specialized design to accommodate multi-modal devices. Its performance has been evaluated on an anesthetized macaque. Compared to the commercially-available pediatric coil, the 16-channel monkey head coil showed improved receive sensitivity and superior acceleration performance. Further, the presented coil can accommodate multi-modal devices, allowing simultaneous optical imaging, neural recording, and stimulation, during high-field MRI studies. It is hoped that the proposed array coil could benefit a broad scope of research in frontier neuroscience.

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Optimization of small animal RF coil with co-simulation approach
Xinqiang Yan1,2, Feng Wang1,2, and John C. Gore1,2

1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Radiology and Radiological Science, Vanderbilt University, Nashville, TN, United States

The 3D electromagnetic and RF circuit co-simulation approach is a fast and accurate tool to calculate the EM fields of RF coils. It is typically used for human coils to evaluate the transmit field and SAR. In this work, we apply this method to the circuit optimization of a small animal coil. Unlike human coils, the coil noise of small animal coil is not neglectable and should be minimized. With the guide of co-simulation approach, an optimized saddle-shaped surface coil has considerable transmit efficiency and SNR improvement on ex-vivo squirrel monkey brain imaging at 9.4T.

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A transceive array with passively fed dipoles and shielded loop coils for laryngeal imaging at 7T
Thomas Ruytenberg1, Andrew G Webb1, and Irena Zivkovic1

1C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands

A transceive array for laryngeal imaging at 7T was constructed, consisting of 5 shielded loop coils and 3 passively fed dipoles. The array is physically flexible due to the absence of lumped elements in the loops and shows very high inter-element isolation (greater than -19 dB) without implementing decoupling circuits, even though the elements are closely packed. After RF shimming using the array,  high resolution turbo spin-echo images were acquired from a healthy volunteer.

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Triple Tuned 6-element Asymmetric Mode Ladder-Resonator/Transceive-Array for Thoracic Imaging of 19F/1H at 1.5T and 129Xe/19F at 3T
Adam Maunder1, Graham Norquay1, Oliver I Rodgers1, Fraser Robb1,2, Madhwesha Rao1, and Jim Wild1

1Unit of Academic Radiology, University of Sheffield, Sheffield, United Kingdom, 2GE Healthcare Inc., Aurora, OH, United States

A 6-element triple-tuned asymmetric mode ladder-resonator/transceive-array was constructed in order to allow direct field strength comparisons of 19F/1H imaging at 3T and 1.5T using the same coil geometry, and to compare 129Xe and 19F imaging at 3T. The designed array is the first instance of triple-tuning a coil by replacing tuning capacitors with LC networks to provide the equivalent reactance needed for coil tuning at three Larmor frequencies (35MHz, 60MHz and 120MHz). Details on construction and simulation are provided and phantom imaging performed for 19F/1H at 1.5T and 19F at 3T, as well as in-vivo imaging of hyperpolarized 129Xe at 3T, demonstrate the functionality of the coil.

1530
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Comparative design study of a 3T 1H RF breast coil: Quadrature vs. Solenoid Design
Sören Bieling1,2, Mark E. Ladd1,2,3, and Arthur W. Magill1

1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3Faculty of Medicine, Heidelberg University, Heidelberg, Germany

In this work a comparative design study for the development of a new proton (1H) transmit/receive  radio frequency (RF) coil for unilateral breast imaging at 3 Tesla (123MHz) is performed. The two most common RF breast coil designs, based on quadrature and solenoid coils, are compared against each other in terms of spatial homogeneity and first-order statistics (mean µ, standard deviation σ, spread σ/µ) of the circularly polarized RF excitation field (B1+) as well as B1+ scaled over the square root of the maximum 10g-averaged specific absorption rate (B1+/√(SARpeak)).

1531
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Investigation of an artificial line π LC BALUN as a single-stage impedance transformation network, for direct preamplifier and coil matching in MRI surface array coils.
Miheer Mayekar1, Tejkiran Patil1, Tapas Bhuiya1, and Rajesh Harsh1

1Technology Innovation Department, Society for Applied Microwave Electronics Engineering and Research, Mumbai, India

Previous studies have shown that the coil matching network (CMN) and preamplifier input matching network (IMN) can be combined to match the coil loop to the transistor in the preamplifier directly. Through simulations we have shown that the artificial line ‘π’ LC BALUN can be used to match the coil loop to the transistor in the preamplifier directly. Though ‘L’ section LC BALUN is widely used in surface array coils to create high blocking impedance across coils, it has several limitations. Hence, artificial line LC BALUN can be used as impedance transformation network and as a common-mode choke simultaneously. 

1532
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Design of multi-row multi-channel degenerate birdcage array coil based on minimum total reflection for the single-channel and circularly polarized modes of excitation
Ehsan Kazemivalipour1,2, Alireza Sadeghi-Tarakameh1,2, Umut Gundogdu2, and Ergin Atalar1,2

1Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey

We propose that a transmit coil can be optimized for certain modes of operation. It is well-known that when the number of channels of a degenerate birdcage coil increases coupling between channels becomes a significant problem. The high total reflection when only one of its channels is used as a transmitter caused a small portion of the power delivered to the body. However, when it is properly designed, in some modes of operations such as circularly-polarized mode, the total reflection become negligibly small. In this work, we demonstrate this effect on various two-row degenerate birdcage-coils together with simulations and experiments.

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Understanding the physical origins behind the noise navigator
Robin Navest1, Stefano Mandija1, Anna Andreychenko1,2, Jan Lagendijk1, and Cornelis van den Berg1

1Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands, 2ITMO University, Saint Petersburg, Russian Federation

Thermal noise is ever-present in any MR experiment and can be used for motion detection. To investigate the physical origins behind the noise navigator, electromagnetic simulations were performed on a realistically moving human model. Tissue displacement affects the thermal noise distribution more than dielectric lung property alterations and the difference between 15 and 20 cm coil size is negligible. The differential noise matrix obtained from electromagnetic simulations is a good means to gain understanding on the spatial sensitivity to motion in particular body regions. This understanding can be used to guide optimization and develop new applications (e.g. motion tracking) of the noise navigator.


MRI Unplugged: Wireless, Portable & Flexible

Exhibition Hall
Monday 9:15 - 10:15
 Engineering

1534
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Wireless Power Transfer Compatibility and Noise Issues in MRI
Kelly Byron1, Fraser Robb2, Shreyas Vasanawala3, John Pauly1, and Greig Scott1

1Electrical Engineering, Stanford University, Stanford, CA, United States, 2GE Healthcare, Aurora, OH, United States, 3Radiology, Stanford University, Stanford, CA, United States

To achieve completely wireless coil arrays, several watts of power will need to be delivered with minimal impact on the MR images.  Wireless power transfer (WPT) has been previously developed to efficiently transfer power, however, harmonics are generated and low frequency noise can be up-converted by both the DC-to-RF conversion and the RF-to-DC rectification of the WPT system.  Efficiency can be traded off to reduce noise through additional filtering and rectifier choice, and by replacing the switching supply to the power amplifier with batteries an ultimate SNR performance within 6dB of the ideal can be achieved while continuously transferring power.

1535
Computer 102
Harvesting Power Wirelessly from MRI Scanners
Kelly Byron1, Fraser Robb2, Shreyas Vasanawala3, John Pauly1, and Greig Scott1

1Electrical Engineering, Stanford University, Stanford, CA, United States, 2GE Healthcare, Aurora, OH, United States, 3Radiology, Stanford University, Stanford, CA, United States

As the number of devices accompanying patients inside the MRI bore increases, so does the need for reliable powering inside the MRI.  The high-power B1 field in MRI suggests the capability to harvest power wirelessly from the scanner itself.  With high quality factor coils and a high efficiency class-E rectifier we are able to harvest 100s of µJ /TR.  However, B1 harvesting will generate flip angle banding when harvesting loops are near imaging regions.  These banding artifacts increase with increasing coil size and decrease with larger coil loading.  

1536
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Universal WiGig MRI receiver platform with auto-synchronised clock module and ZYNQ-based high-speed digitizer
Yunkyoung Ko1, Wenwei Bi1, Jörg Felder1, and N. Jon Shah1,2,3,4

1Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich, Juelich, Germany, 2Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Juelich, Germany, 3JARA - BRAIN - Translational Medicine, Aachen, Germany, 4Department of Neurology, RWTH Aachen University, Aachen, Germany

The operation of 60GHz data transmission inside the MR room using the WiGig standard has been demonstrated in a previous study. It offers an off-the-shelf solution for reliable, high-speed data transmission as required by modern high-channel-count array coils. However, wireless data transmission is only one component of a complete receiver chain in MRI. Since the ARM-based platform employed in our previous study is not powerful enough to implement full high-speed high-fidelity acquisitions, we propose to connect the WiGig data link with a FPGA board, clock generator board and a high-precision ADC board to increase the speed and the fidelity.

1537
Computer 104
Wireless Digital Data Transfer based on WiGig/IEEE 802.11ad with Self-Shielded Antenna Gain Enhancement for MRI
Yunkyoung Ko1, Wenwei Bi1, Jörg Felder1, and N. Jon Shah1,2,3,4

1Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich, Juelich, Germany, 2Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Juelich, Germany, 3JARA - BRAIN - Translational Medicine, Aachen, Germany, 4Department of Neurology, RWTH Aachen University, Aachen, Germany

Here we investigate the feasibility of using existing high data rate wireless transmission protocols - a wireless gigabit (WiGig) - suitable for transmitting data from high channel count array antennas. Moreover, the study aims to use off-the-shelf commercial components that, with only minor modifications, allow for maximum flexibility of the implementation. The system presented here overcomes these shortcomings by increasing the antenna gain and provides a practical solution for the wireless transmission of receive signals.

1538
Computer 105
Restraint system with integrated receive array for minimizing head motion during awake marmoset imaging
Kyle M Gilbert1, David J Schaeffer1, Stefan Everling1, and Ravi S Menon1

1Centre for Functional and Metabolic Mapping, The University of Western Ontario, London, ON, Canada

Marmoset monkeys are an increasingly popular animal model for functional MRI studies due to their close homology with humans. To negate the confounds of anesthesia on brain activation, marmosets can be imaged awake. A restraint chair with an integrated receive array is described for minimizing motion during awake imaging. Motion was limited to 129 μm and 0.41°, allowing for comparable temporal SNR with respect to anesthetized imaging.

1539
Computer 106
About the MRI compatibility of fuel cells as the power source for PET detectors
Nicolas Gross-Weege1, Thomas Dey1, Bjoern Weissler1, Teresa Nolte1,2, Johannes Ramler3, Martin Müller4, Detlef Stolten3,4, and Volkmar Schulz1

1Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany, 2Philips Research Europe, Eindhoven, Netherlands, 3Chair for Fuel Cells, RWTH Aachen University, Aachen, Germany, 4Institute of Energy and Climate Research, IEK-3: Electrochemical Process Engineering, Forschungszentrum Jülich GmbH, Jülich, Germany

Since MRI is very sensitive regarding electromagnetic disturbances, the integration of a Positron Emission Tomography (PET) detector into in an MRI system is a sophisticated task. The power supply and cabling of the PET detectors are the main sources of electromagnetic interferences with the MRI. Therefore, we propose to power the PET detectors with a proton-exchange membrane fuel cell (PEMFC). To prove the feasibility of the concept, we evaluated the MRI compatibility of the PEMFC. The PEMFC was able to power PET detectors and only a minor influence of the PEMFC on the B0 homogeneity and noise level was measured.

1540
Computer 107
Ultra-Flexible Electro-Textile 4-Channel MRI RF Coil Array for Neck MRI
Daisong Zhang1, Le Zhang2, Ashley Prosper2, Holden H. Wu2, and Yahya Rahmat-Samii1

1Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, CA, United States, 2Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States

Current surface coils used for neck MRI are either uncomfortable for patients to wear or suffer from low Signal-to-Noise Ratio (SNR). Electro-textile conductive material was utilized in this work to design a new ultra-flexible 4-channel receive-only RF coil array for neck MRI. The flexibility of the material is similar to normal clothes thus leading to considerable ergonomic benefit. The SNR at 0.5 cm and 3 cm are 27 and 5.5 times higher than a conventional surface array coil, respectively. Cadaver images acquired using the new ultra-flexible coil had good depiction of anatomical features such as vertebral arteries and sternocleidomastoid muscles.

1541
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Simulations of Integrated Radio-Frequency/Wireless Coil Designs for Simultaneous MR Image Acquisition and Wireless Communication
Julia Bresticker1,2, Zachary Thompson1, Devin Willey1,2, Allen W Song1,2, Dean Darnell1,2, and Trong-Kha Truong1,2

1Medical Physics, Duke University, Durham, NC, United States, 2Brain Imaging and Analysis Center, Duke University, Durham, NC, United States

A novel RF coil design, termed an RF/wireless coil, enables simultaneous image acquisition and wireless communication by allowing currents to flow simultaneously at the Larmor and WIFI frequencies. Measurements of the far-field radiation parameters are not practical in an MRI scanner. Thus, simulations are performed to optimize the far-field performance within the scanner bore to maintain the wirelessly transmitted data integrity. In this work, finite element simulations, verified with anechoic chamber gain-pattern measurements and SNR maps from a constructed RF/Wireless coil, are performed to optimize the far-field gain, directivity, and link budget of the RF/Wireless coil within the scanner bore. 

1542
Computer 109
Clock Transmission Methods for Wireless MRI: A Study on Clock Jitter & Impact on Data Sampling
Jonathan Y Lu1, Thomas Grafendorfer2, Fraser Robb3, Simone Winkler4, Shreyas Vasanawala4, John M Pauly1, and Greig C Scott1

1Electrical Engineering, Stanford University, Stanford, CA, United States, 2GE Healthcare Inc, Stanford, CA, United States, 3GE Healthcare Inc, Aurora, OH, United States, 4Radiology, Stanford University, Stanford, CA, United States

Creating wireless MRI receive coils requires the clock for the on-coil electronics to be in phase with the clock of the MRI transmit system. Sending a wireless clock using a phase locked loop (PLL) single tone that is divided down versus a dual tone AM double side band suppressed carrier (AM DSB-SC) system can have different results in jitter of the clock. We experiment with these architectures,. The wireless clock transfer methods will ultimately impact SNR of the ADC system and its robustness to phase changes from environmental scenarios such as patient motion or multipath effects.

1543
Computer 110
Characterization of In-Bore 802.11ac Wi-Fi Performance
Christopher Vassos1, Fraser Robb2, Shreyas Vasanawala3, John Pauly1, and Greig Scott1

1Electrical Engineering, Stanford University, Stanford, CA, United States, 2GE Healthcare, Aurora, OH, United States, 3Radiology, Stanford University, Stanford, CA, United States

In the context of flexible wireless coil arrays, characterization of achievable data rates is critical. This understanding will impact the types of scans whose data rates can be achieved in a wireless framework. The MR environment includes a cylindrical reflector as well as high power RF pulses, both of which may interfere with wireless communication inside the bore. By utilizing an embedded development platform, the relative impacts of the MR environment on Wi-Fi data rate were characterized and found to have little effect on the rate of data transfer.  

1544
Computer 111
A Novel and Efficient No-tuning Inductive-coupling Q-damping Circuit for a Low-field Portable MRI System
Zhi Hua Ren1, Guang Yang2, Pengde Wu3, Sergei Obruchkov2, Robin Dykstra2, and Shao Ying Huang1

1Singapore University of Technology and Design, Singapore, Singapore, 2Victoria University of Wellington, Wellington, New Zealand, 3Sichuan University, Chengdu, China

In a low-field portable MRI system, e.g. a permanent-magnet-based system, $$$B_0$$$ is less homogeneous thus $$$T_2^*$$$ is short. However, the ring-down of the transmit RF energy is slow, which dramatically decreases the strength of acquired signals or limits the minimum echo time for a CPMG type experiment. In this abstract, we present the design of a no-tuning inductive-coupling Q-damping circuit for transmit-coils in a low-field MRI/NMR system. The proposed circuit can effectively and quickly damp RF energy yet simple to be implemented and constructed. The effectiveness is successfully demonstrated in simulations and experimentally. In the experiment, it shows that the ring-down time is reduced by about 45%.

1545
Computer 112
An Aubert Ring Aggregate Magnet Helmet for 3D Head Imaging in a Low-field Portable MRI
Zhi Hua Ren1 and Shao Ying Huang1,2

1Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore, 2Department of Surgery, National University of Singapore, Singapore, Singapore

A permanent magnet helmet based on an Aubert ring aggregate is proposed to have a linear gradient along the axial direction for 3D head imaging in a low-field portable MRI system. It is a magnet array that consists of a series of asymmetric Aubert ring pairs, forming a Helmet shape. The inner radii of each ring are successfully optimized for a linear gradient along the axial direction, a comparably strong field strength (67.06mT), and a controlled  homogeneity. Genetic Algorithm (GA) was used for the optimization. This design can be used to supply B0 in a miniaturized low-field portable MRI system.   

1546
Computer 113
Design of a novel class of open MRI devices with nonuniform Bo, field cycling, and RF spatial encoding
R. Todd Constable1, Charles Rogers III2, Baosong Wu1, Kartiga Selvaganesan1, and Gigi Galiana2

1Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States, 2Radiology and Biomedical Imaging, Yale School of Medicine, New, CT, United States

This work describes a novel approach to the design of MRI systems that combines 4 existing developments in order to create a new class of MRI devices. The developments to be described include combining parallel RF receive, Bloch-Siegert phase encoding, nonlinear spatial encoding, and field cycling. Together these methods allow for open magnets with nonuniform main fields greatly increasing design opportunities for small magnets with specific applications. The relatively low cost of this class of MR devices will allow for the placement of MRIs in doctor’s offices where they could be built into an examination table.  

1547
Computer 114
A Novel Ultra-Flexible High-Resolution 50-Channel RF Coil for Prostate, Rectal and Pelvis Imaging
Yun-Jeong Stickle1, Clyve Konrad Follante1, Mark Giancola1, Fraser Robb1, Victor Taracila1, Balint Franko1, Holly Blahnik2, and Robert S Stormont2

1MR Engineering, GE Healthcare, Aurora, OH, United States, 2MR Engineering, GE Healthcare, Waukesha, WI, United States

Typically, posterior with anterior array or Large/Medium MSK coils or endorectal coil are used for prostate and rectal imaging. These coils do not provide deep depth, high-resolution and acceleration images. A novel high-resolution flexible phased-array coil for Prostate, Rectal and Pelvis Imaging is presented. This coil contains a posterior base with two lateral flaps and one center flap with wire loops providing a light weight flexible conforming coverage to prostate, rectal and pelvis. This close fitting high density 50-Channel coil provides better diagnostic images and comfort. This coil also introduces new thin flexible materials including two thermoplastic coated thin fabrics.

1548
Computer 115
A light-weight, flexible head and neck coil design for a patient-friendly MR-only Radiation Therapy workflow
Cristina Cozzini1, Chad Bobb2, Mathias Engström3, Sandeep Kaushik4, Robert Molthen2, Dan Rettmann5, Venkat Goruganti6, Wen-Yang Chiang6, and Florian Wiesinger1

1GE Healthcare, Munich, Germany, 2GE Healthcare, Waukesha, WI, United States, 3GE Healthcare, Stockholm, Sweden, 4GE Global Research, Bangalore, India, 5GE Healthcare, Rochester, MN, United States, 6NeoCoil, Pewaukee, WI, United States

MRI is known to provide a superior soft tissue contrast when compared to CT. MR simulation offers the potential of improving target and organ at risk delineation and is therefore playing an increasingly important role in the Radiation Therapy (RT) planning workflow. Here a lightweight, highly flexible, novel coil prototype for head and neck is presented, demonstrating that a patient friendly MR-only simulation workflow for standard MR imaging and pseudo CT conversion is feasible in a clinical setting and compatible with RT fixation devices.

1549
Computer 116
Design of a reconfigurable endoluminal coil using MEMS switches
Hamza Raki1,2, Kevin Tse Ve Koon1, Henri Souchay2, Fraser Robb3, Simon A. Lambert1, and Olivier Beuf1

1Univ Lyon, INSA‐Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F‐69616, Lyon, France, 2General Electric Healthcare, Buc, France, 3General Electric Healthcare, Aurora, OH, United States

Endoluminal Magnetic Resonance Imaging (MRI) is an alternative solution to conventional MRI, which is still not sufficient to image the bowel and colon wall. However, it mainly suffers from coil-sensitivity-map variations with coil-orientations within respect to the main magnetic field (B0). The purpose of this work was to study numerically different coil-geometries and their performances when positioned in different orientations regarding B0. From the simulation results, a solution of a reconfigurable endoluminal-coil using four MEMs switches is proposed. Electro-Magnetic (EM) simulation demonstrated the feasibility to reduce the coil-sensitivity variations by using a combination of Single-loop (SL) and Double-Turn-Loop (DTL) configurations.

1550
Computer 117
Flexible multi-turn multi-gap coaxial RF coils: enabling a large range of coil sizes
Raphaela Czerny1, Lena Nohava1,2, Roberta Frass-Kriegl1, Jacques Felblinger3, Jean-Christophe Ginefri2, and Elmar Laistler1

1Division MR Physics, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, 2IR4M (Imagerie par Résonance Magnétique et Multi-Modalités), Université Paris-Sud, CNRS, Université Paris-Saclay, Orsay, France, 3Université de Lorraine, Inserm, IADI, Nancy, France

Flexible single-turn coaxial RF coils with one gap in the outer and one gap in the inner conductor are restricted to a specific geometry, determined by the target resonance frequency and the specifications of the cable used. In this work we demonstrate by numerical simulations that, by combining the concept of coaxial coils with that of multiple turns and gaps transmission line resonators (MTMG TLRs) and the additional degree of freedom offered by varying the cable parameters, a large diameter range can be achieved to design 1H RF coaxial coils for most common B0 field strengths.

1551
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A Transceive Inductively Coupled Coil using Dual Wireless Coils for Small Animal Imaging at 15.2T
SooBum Kim1, DongHyuk Kim1, Won Beom Jung2,3, and KyungNam Kim1

1Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, Korea, Republic of, 2Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, Korea, Republic of, 3Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, Korea, Republic of

The ultrahigh field 15.2 T Magnetic Resonance Imaging (MRI) is characterized by high magnetic flux density (B1) sensitivity and uniformity. Therefore, it is mainly used for small animal images requiring high resolution. Generally, surface coils are used to obtain high B1 sensitivity to target brain at small animal MRI, but occasionally there is insufficient coverage to cover all of the Region of Interest, so that the desired information may not be obtained. In this study, we propose a coil with wider coverage using inductively coupling by adding dual wireless coils to one channel transceive primary coil at 15.2 T.

1552
Computer 119
Resonant and non-resonant coupled-wire coils for small-animal multinuclear imaging
Tania S. Vergara Gomez1,2, Marc Dubois1, Stanislav Glybovski3, Benoit Larrat4, Julien de Rosny5, Carsten Rockstuhl6,7, Monique Bernard2, Redha Abdeddaim1, Stefan Enoch1, and Frank Kober2

1Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France, 2Aix Marseille Univ, CNRS, CRMBM- UMR 7339, Marseille, France, 3Department of Nanophotonics and Metamaterials, ITMO University, St. Petersburg, Russian Federation, 4Commissariat à l’Energie Atomique et aux Energies Alternatives, Direction de la recherche Fondamentale, NeuroSpin, Université Paris Saclay, Gif-sur-Yvette, France, 5ESPCI Paris, PSL Research University, CNRS, Institut Langevin, Paris, France, 6Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany, 7Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany

Metasurface coils coupled with an unmatched loop were suggested earlier as an alternative to classical surface and volume coils, with the aim to optimize volume and sensitivity.  We developed a new approach combining a commercial surface coil and a non-resonant coupled-wire structure. With this approach, the signal contribution from the driving loop can be efficiently added to that of the wire surface. The configuration was simulated, built and tested for 1H and 19F at 7T. The results showed that this new strategy improves the coil's sensitive volume while simultaneously maintaining high SNR.

1553
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Imaging of Stroke in Rats using a Clinical Scanner and an Inductively Coupled Specially Designed Receiver Coil
Ignacio Iñigo1, Javier Istúriz2, Miguel Fernández3, Maria J. Nicolas1, Pablo Domínguez3, Gorka Bastarrika 3, Miguel Valencia1, and María A. Fernández-Seara3

1Systems Neuroscience Lab, Centro de Investigación Médica Aplicada, Pamplona, Spain, 2Neos Biotec, Pamplona, Spain, 3Radiology, Clínica Universidad de Navarra, Pamplona, Spain

Imaging of small laboratory animals in clinical MRI scanners is feasible but challenging. Compared with dedicated preclinical systems, clinical scanners have relatively low main field (1.5 – 3.0 T) and gradient strength (40 – 60 mT/m). This work explores the use of wireless inductively coupled coils combined with adapted pulse sequences to overcome these two drawbacks, with a special emphasis on the optimization of the coil passive detuning circuit for this application. The images of rat brain stroke obtained show a substantial increase in SNR compared to clinical coils, and the absence of wires makes the animal preparation workflow straightforward.

1554
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Title: Enhancement of SNR and Sensitivity of Image in MR using Left Handed Metamaterial Lens Focusing/Converging in both direction.
Tejkiran A. Patil1, Bhaskara Naik1, and Rajesh Harsh1

1Technology Innovation Department, Society for Applied Microwave Electronics Engineering and Research, Mumbai, India

Enhancement of the signal received by the surface coil is one of the interesting area to increase the SNR. Left Handed Metamaterial Lens have shown application in MRI to increase the signal strength at its converging point. We have reported the increase in  receiver sensitivity by around 5 dB. In this report SNR and Sensitivity is further improved by incorporating metamaterial lens in between 2 receive chain of a 4-channel hexagonal shaped flex array coil is presented. With this method SNR is improved by 1.4 times.

1555
Computer 122
Investigation of antenna effect on non-contact monitoring of heart and respiration rate
Takafumi Ohishi1

1Research and Development Center, Canon Medical Systems Corporation, Kanagawa, Japan

This paper investigates a non-contact heart and respiration rate monitoring with antennas. In order to examine antenna effect on the non-contact monitoring, differences of antenna resonant frequency or antenna type are investigated by experiment. In the experiment, it is found that the higher the antenna resonant frequency is, the easier the heart rate is identified. In addition, it is shown that by using only one open circuit end type dipole antenna, both the heart and respiration rate in spine posture can be identified. 

1556
Computer 123
Sensitivity and Uniformity Improvement of Phased Array MR Images Using Inductive Coupling and RF Detuning Circuits
Bu Sik Park1, Sunder Rajan2, and Brent McCright1

1Division of Cellular and Gene Therapies (DCGT), FDA, Silver Spring, MD, United States, 2Division of Biomedical Physics (DBP), FDA, Silver Spring, MD, United States

This study demonstrates improvement in MR image sensitivity and uniformity from a 4-channel phased array using a secondary resonator having switchable detuning circuits. The secondary resonator was located at the opposite side of the 4-channel phased array to improve sensitivity and uniformity of the acquired MR images. The numerical simulation results of |B1+| in a transmit mode showed the magnetic field uniformity would be decreased with the designed secondary resonator having no detuning circuits because of unwanted interferences between the transmit birdcage coil and the secondary resonator. Whereas, the sensitivity and uniformity of |B1-| in a receive mode were improved with the secondary resonator and a 4-channel phased array. For experimental verification, a uniform saline phantom and mice were analyzed by MR using a 7.0T small animal MRI system. 

1557
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Metasurface-based wireless coil to control RF magnetic field distribution inside 1.5T MR scanner.
Egor Kretov1, Alena Shchelokova1, and Alexey Slobozhanyuk1

1ITMO University, Saint Petersburg, Russian Federation

We demonstrate a new metasurface-based wireless coil for 1.5T MRI. A simple working frequency adjusting method let using it in a wide frequency range up to 5 MHz that make it compatible with MRI systems of different manufacturers. The design of the coil allows manipulating the radiofrequency magnetic field profile inside the large body coil improving its transceive efficiency in the target area. Phantom imaging with proposed coil approves that by changing the size of the working region is also possible to decrease the excitation power needed to provide optimal flip angle.

1558
Computer 125
Ultra-flexible and light-weight 3-channel coaxial transmission line resonator receive-only coil array for 3T
Michael Obermann1, Lena Nohava1,2, Sigrun Goluch-Roat1, Michael Pichler1, Jürgen Sieg1, Jacques Felblinger3, Jean-Christophe Ginefri2, and Elmar Laistler1

1Division MR Physics, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, 2IR4M (Imagerie par Résonance Magnétique et Multi-Modalités), UMR 8081, Université Paris-Sud/CNRS, Université Paris-Saclay, Orsay, France, 3Université de Lorraine, Inserm, IADI, Nancy, France

An ultra-flexible light-weight coaxial coil array with compact interfaces is introduced. The interfaces consist of components for tuning, active detuning, matching and preamplifier decoupling. Bench and MR tests of the array are presented and the robustness with regard to bending is demonstrated.


Dielectrics, Decoupling, Switching & Control

Exhibition Hall
Monday 9:15 - 10:15
 Engineering

1559
Computer 126
A PIN-diode-driver for fast coil tuning using low detune currents
Michael Eder1, Andreas Horneff1,2, Erich Hell2, Johannes Ulrici2, and Volker Rasche1

1Experimental Cardiovascular Imaging Group, University Hospital of Ulm, Ulm, Germany, 2Research, Development and Technology (GBE), Sirona Dental Systems GmbH, Bensheim, Germany

To operate ultra short echo time (UTE) or zero echo time (ZTE) imaging, the ability to switch rapidly from detuned to tuned state is mandatory, as any delay causes signal loss for UTE or missing data points in the k-space center for ZTE. While propagation delays arising during radio frequency (RF) front end control can be measured and compensated, the dead time of the receive coil remains a limiting factor. In this contribution we investigated an approach to speed up PIN-diode based coil-tuning, using a dedicated driver providing a low detune current. Tuning times below $$$1000\,\mathrm{ns}$$$ could be realized.

1560
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UTE and ZTE on an unmodified clinical whole-body MR system using an RF signal acquisition system operating in parallel achieving an acquisition delay of less then $$$2\,\mathrm{\text{µ}s}$$$
Michael Eder1, Andreas Horneff1,2, Jan Paul2, Alexander Storm3, Erich Hell2, Johannes Ulrici2, and Volker Rasche1

1Experimental Cardiovascular Imaging Group, University Hospital of Ulm, Ulm, Germany, 2Research, Development and Technology (GBE), Sirona Dental Systems GmbH, Bensheim, Germany, 3Ulm University, Ulm, Germany

Ultra short echo time and zero echo time imaging on clinical systems are, even on modern systems, still limited by the rather long transient time required for switching from transmit to receive mode. In this contribution a complete receive-only chain was interfaced to an unmodified clinical whole-body MR system. Synchronization is achieved by a single trigger line as temporal reference and a time base signal, thus ensuring minimal interference and phase synchronous operation in parallel to the clinical system. An acquisition delay, between the real end of the excitation pulse and the beginning of signal acquisition, below $$$2\,\mathrm{\text{µ}s}$$$ could be realized.

1561
Computer 128
Necessity for detuning large volume coils?
Ria Forner1, Martijn Lunenburg2, Quincy van Houtum1, Ladislav Valkovic3, Jane Ellis3, Christopher T. Rodgers4, and Dennis Klomp1

1UMC Utrecht, Utrecht, Netherlands, 2MR Coils BV, Zaltbommel, Netherlands, 3Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, JR Hospital, Oxford, United Kingdom, 4Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom

Implementing diode detuning on transmit coils is complicated and leads to a loss in efficiency on the transmit side. It has been common practice to include it nevertheless with the aim of preventing loss of receive efficiency and noise correlation between receiver through coupling via the body coil. However, nowadays, receiver coil elements are orders of magnitude smaller so flux linkage is intrinsically low. Moreover, the operating frequency is high to maintain strong tissue-loading, and finally preamplifier decoupling is applied to reduce the effects of mutual coupling. Here we show the coupling to receiver arrays for three non-detuned body coils.

1562
Computer 129
Traveling-Wave Excitation for Electron Paramagnetic Resonance Imaging
Bahareh Behzadnezhad1,2, Nader Behdad1, and Alan B. McMillan2,3

1Electrical Engineering, University of Wisconsin-Madison, Madison, WI, United States, 2Radiology, University of Wisconsin-Madison, Madison, WI, United States, 3Medical Physics, University of Wisconsin-Madison, Madison, WI, United States

One primary factor limiting the extension of electron paramagnetic resonance imaging (EPRI) beyond small animal applications is the challenge of create uniform RF fields at the higher RF frequencies needed to achieve the desired sensitivity. In this abstract, we discuss the development of a traveling-wave spectrometer operating in continuous-wave mode at 115 MHz. The spectrometer uses a parallel-plate waveguide supporting transverse electromagnetic waves to create a uniform transmit field and uses a conventional receive coil. We demonstrate the feasibility of a traveling wave system and its potential to be developed into an EPR imaging system.

1563
Computer 130
A switch matrix to enable passive cloaking of a metasurface resonator for MRI applications
Shimul Chandra Saha1,2, Roberto Pricci1,2, Maria Koutsoupidou1,3, Ditjoni Katana1, Srinivas Rana3, Helena Cano-Garcia1,2, Panagiotis Kosmas1,3, George Palikaras1,2, and Efthymios Kallos1,2

1Medical Wireless Sensing Ltd, London, United Kingdom, 2Metamaterial Technologies Inc., Dartmouth, NS, Canada, 3Department of Informatics, King's College London, London, United Kingdom

We present a switch matrix for automatic tuning and detuning of a metasurface-resonator employed to enhance MRI scanning performance. A digital circuit with an inductor was used to pick up the magnetic field and generate a clock for switching which does not require any wire connection to the MRI scanner. The clock was used to activate an array of MOSFET switches, each of them connected to an adjacent pair of parallel wires of the resonator. The circuit was tested using a solenoid and the metasurface  resonance frequency was successfully tuned and detuned (cloaked) when the magnetic field was off-on respectively.

1564
Computer 131
Effects of Parallel Imaging Acceleration on SNR Improvement with a High-Permittivity Helmet Shaped Former at Different Field Strengths
Giuseppe Carluccio1,2, Bei Zhang1,2, Riccardo Lattanzi1,2, Gregor Adriany3, Kamil Ugurbil3, and Christopher Michael Collins1,2

1Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York, NY, United States, 2Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York, NY, United States, 3University of Minnesota, Minneapolis, MN, United States

Use of high-permittivity materials has recently shown very promising results in terms of reduction of B1 inhomogeneities and increase of SNR. In particular, significant SNR increases have been predicted for a  high-permittivity helmet former within a close fitting head array. With this solution, for a 7T MRI system, an average SNR increase approaching 50% was obtained in the brain with SNR peak improvements of more than 200%. Until now, however, the effects of the high-permittivity helmet on g-factor and parallel imaging have not been examined. In this work, for three different acceleration rates we evaluate the impact of gfactor when a high-permittivity helmet shaped former is used in two different head arrays at two different field strengths.

1565
Computer 132
The miniaturisation and simplification of a crossbar switch matrix system using stacked switch blocks
Yunkyoung Ko1, Chang-Hoon Choi1, N. Jon Shah1,2,3,4, and Jörg Felder1

1Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich, Juelich, Germany, 2Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Juelich, Germany, 3JARA - BRAIN - Translational Medicine, Aachen, Germany, 4Department of Neurology, RWTH Aachen University, Aachen, Germany

The crossbar-type matrix creates open-stubs of varying length, depending on the switch configuration, which potentially degrades the MR image quality. However, this issue can be overcome efficiently with the use of a compensation circuit. But as the number of receive coils increases, a larger number of RF switches is required. In this study, we propose a miniaturised crossbar switch matrix which employs two independent, stacked boards.

1566
Computer 133
On the Relationship Between Field Strength and Permittivity for Desired Effects of High-Permittivity Materials in MRI
Christopher M Collins1, Giuseppe Carluccio1, Bei Zhang1, Gregor Adriany2, Kamil Ugurbil2, and Riccardo Lattanzi1

1Radiology, New York University, New York, NY, United States, 2Radiology, University of Minnesota, Minneapolis, MN, United States

Experience and general understanding dictate that greater relative permittivity is required to produce a similar effect at lower B0 field strengths and B1 frequencies. Here we use some fundamental explanations and preliminary numerical results for improving receive array performance at different field strengths to propose, more specifically, that permittivity should increase approximately with the inverse of the square of the field strength for an expected effect.

1567
Computer 134
MEMS-based Ratio Adjustable Power Splitters for in-bore Switching of Transmit Array Compression Networks
Charlotte R Sappo1,2, Gabriela L Gallego3, Xinqiang Yan2,4, and William A Grissom1,2,4,5

1Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 3Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, United States, 4Department of Radiology, Vanderbilt University, Nashville, TN, United States, 5Department of Electrical Engineering, Vanderbilt University, Nashville, TN, United States

A large number of coils in parallel transmission enables higher excitation accuracy with lower SAR, but the high cost and siting challenges associated with transmit amplifiers and their cabling has limited the number of channels to 8 on most 7T scanners. Array compressed parallel transmission overcomes this limitation using hardware networks that enable a large number of coils to be optimally driven by a small number of channels. These networks comprise ratio adjustable power splitter (RAPS) circuits that use hybrid couplers with reflection capacitors to apply relative phase shifts between signal branches that can be tuned to set the power ratios of the coil outputs. Here we describe and evaluate a MEMS-RAPS circuit that uses MEMS switches to switch between terminator capacitors, allowing dynamic remote tuning of output power ratios for more flexible transmit array compression networks.

1568
Computer 135
Effect of high dielectric constant material configurations on the transmission field of an 8-channel dipole array at 10.5 T (447 MHz)
Navid PourramzanGandji1, Sebastian Rupprecht1, Michael Lanagan2, Bei Zhang3, Riccardo Lattanzi3, Russell L. Lagore4, Jerahmie Radder4, Gregor Adriany4, Kamil Ugurbil4, and Qing X Yang1

1Pennsylvania State University, College of Medicine, Hershey, PA, United States, 2Department of Engineering Science and Mechanics, Pennsylvania State University, State college, PA, United States, 3Department of Radiology, The Bernard and Irene Schwartz Center for Biomedical Imaging, New York University, New York, NY, United States, 4Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

We used numerical simulations to investigate the effect of high dielectric constant materials (HDCM) on the performance of a transmit array with 8 dipole antennas for 10.5 T head MRI. Several parameters, including B1+ transmit efficiency, coupling between each array elements, and Specific Absorption Rate (SAR), were evaluated in the presence of HDCM with various relative permittivity values. We show that employing HDCM can decrease the coupling between each adjacent element by 16%, increase B1+ efficiency by more than 30% and lower total SAR by 40%.

1569
Computer 136
Quality assurance of 8-channel transmit/receive switches for a 32-channel transmit/receive system at 7T UHF MRI
Stefan HG Rietsch1,2, Maximilian N Voelker1,2, Stephan Orzada1, Daniel Leinweber1, Mark E Ladd1,3,4, and Harald H Quick1,2

1Erwin L. Hahn Institute for MR Imaging, Essen, Germany, 2High-Field and Hybrid MR Imaging, University of Duisburg-Essen, Essen, Germany, 3Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany

With increasing number of transmit and receive channels it becomes more and more important to monitor the behavior of the RF chain over time since weaknesses of custom-built hardware need to be known to the investigator. In this work, a quality assurance procedure for four identical 8-channel transmit/receive switchboxes for a 32-channel transmit/receive MR system at 7T is presented. In repeated measurements of a homogeneous phantom with an 8-channel transmit/receive coil, metrics like flip angle distribution, SNR and noise correlation are used to automatically assess quantitatively if significant changes of the hardware did occur.

1570
Computer 137
Bilateral Breast coil for Fast Field-Cycling Relaxometric MRI
Gareth R Davies1, Lionel M Broche1, Tanja Gagliardi2, David J Lurie1, and P. James Ross1

1Biomedical Physics, University of Aberdeen, Aberdeen, United Kingdom, 2Aberdeen Biomedical Imaging Centre, University of Aberdeen, Aberdeen, United Kingdom

Our research group is investigating the use of Fast Field-Cycling MRI (FFC-MRI) for clinical applications. Recent results have confirmed the presence of interesting FFC-MRI biomarkers in breast cancer that could lead to important applications. To study this we are developing an FFC-MRI compatible breast coil for use on patients. This work is presented here and shows excellent results, paving the way to clinical applications.  

1571
Computer 138
Control synchronization of power supplies and gradient amplifiers for better utilization of energy storage in MRI scanner
Yash-Veer Singh1, Juan A Sabate1, Ruxi Wang1, Viswanathan Kanakasabai2, Krishna Mainali1, and Huan Hu1

1GE Global Research, Niskayuna, NY, United States, 2GE GR JFW Technology Center, Bengaluru, India

The magnetic resonance imaging (MRI) gradient driver is a high-performance inverter that provides large peak currents, >1000A, for the gradient magnetic fields used for imaging. MR system has capacitors for energy storage at the amplifier stage input voltages. Volume/weight reduction in energy storage elements is one of the challenging issue in design of compact and efficient MRI gradient system. It is possible to reduce capacitance value in energy storage elements by synchronizing the control of the gradient driver different subsystems. Control synchronization is achieved by providing reference value of coil current simultaneously to the different controller of the MRI system.

1572
Computer 139
A three-element triple-tuned array implemented with switchable matching and tuning
Travis James Carrell1, Romina Del Bosque1, Matthew David Wilcox1, and Mary Preston McDougall1,2

1Biomedical Engineering, Texas A&M University, College Station, TX, United States, 2Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States

This work describes a geometrically decoupled three-element array triple-tuned for 1H, 13C, and 31P at 3T implemented with switchable matching and tuning using PIN diodes. These particular nuclei were chosen to demonstrate the frequency range of the method, but the approach is extendable to any nuclei of interest.   Although the Q of the coils was degraded by the switching network, the use of PIN diodes enabled straightforward tuning and development.

1573
Computer 140
On the minimum phase control required for B1 shimming
Steven M. Wright1

1Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States

Phase only B1 shimming is a cost-effective and simple approach to improving RF field homogeneity for high field MRI.  Without a multiple channel transmitter,  this is implemented by switching transmission lines or possibly lumped element phase shift networks.   This abstract investigates the minimum phase shift required in a potential multi-bit electronic phase shifter.  For practical shimming solutions, those not requiring significant increases in power to achieve a 90 degree tip angle as compared to ‘birdcage’ or conjugate phase currents, it is concluded that 45 degrees may be a sufficient resolution for such a phase shifter. 

1574
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Digitally Controlled High-Power Phase Shifter for B1 Shimming at 7T
Chenhao Sun1, Neal Hollingsworth1, Kevin Patel1, Kasra Ghadiri1, Chung-Huan Huang1, and Steven M. Wright1

1Electrical & Computer Engineering, Texas A&M University, College Station, TX, United States

To mitigate electromagnetic wave interference in high field MRI, RF shimming relies on the ability to manipulate the phase and amplitude of the Tx signal on each channel. The simplest approach is to change phase shifts by switching transmission lines. We propose an electronically controlled phase shifter providing eight different states of phase shifting (0°, 22.5°…...135°, 157.5°), designed to handle 1kW Tx power and is non-magnetic so that it can be used in the magnet room. Measurement demonstrate an average insertion loss of -0.94dB and an average phase error -1.35° compared with design values.

1575
Computer 142
Receiver ring-down attenuation for Ultra-Low field MR
Ruben Pellicer-Guridi1, Michael W. Vogel1, Rainer Körber2, Jan-Hendrik Storm2, Jiasheng Su1, David C. Reutens1, and Viktor Vegh1

1Centre for advanced imaging, University of Queensland, Brisbane, Australia, 2Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

Ultra-low field MR detector coils experience long dead-times which reduce acquisition efficiency. We present a simple low insertion loss Q-damping scheme and a post-processing method that, combined, allow earlier signal acquisition. Proposed methods have been empirically verified with a cylindrical detector at 2.5 kHz. This approach can improve imaging efficiency for ULF MR considerably, promoting the use of inexpensive resistive coils for low-cost, portable ULF MR instruments.

1576
Computer 143
Self-decoupled coils for MRI receiver arrays based in an external resonator
Rafael A. Baron1, Juan D. Sanchez-Heredia1, Vitaliy Zhurbenko1, and Jan H. Ardenkjær-Larsen1

1Technical University of Denmark, Kgs. Lyngby, Denmark

A method of decoupling coils by the use of an external resonator has been developed. The method provides several advantages as a decoupling strategy which does not strongly depend on the input impedance of the amplifier, can use flexible wires and provide a low dependence of the coupling to the position of one coil relative to the other. The concept was initially developed for cryogenic coils due to its simple implementation but is presented to room temperature Copper-based receivers.

1577
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Massively Accelerated Simulations of High-Permittivity Materials in Multi-Channel Receive Arrays
Wyger Brink1, Jeroen van Gemert2, Peter Börnert3, Rob Remis2, and Andrew Webb1

1Leiden University Medical Center, Leiden, Netherlands, 2Delft University of Technology, Delft, Netherlands, 3Philips Research Laboratories, Hamburg, Germany

High-permittivity materials are known to offer potential increases in the sensitivity of RF coils, increasing SNR or reducing SAR. Design guidelines are not straightforward, however, in part due to complex coil interactions. We here present a numerical method for the rapid (e.g. ~1 sec) assessment of dielectric materials positioned in a 3T torso receive array, enabling full exploitation of this technology.

1578
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Water-tunable Spiral Metamaterial Resonator for Radiofrequency Field Enhancement for Receive Coils at 1.5T
Elizaveta Motovilova1, Srikumar Sandeep1, Michinao Hashimoto1, and Shao Ying Huang1,2

1Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore, 2Department of Surgery, National University of Singapore, Singapore, Singapore

We present a low-profile tunable spiral metamaterial resonator for radio-frequency field enhancement and penetration increase for receive coils at 1.5T MRI. The resonator consists of a dielectric substrate with a cavity for water deposition and two conducting spirals placed on each side of the substrate. The proposed structure is placed between a receive loop-coil and a load. The resonance frequency of the coil-spiral system can be varied within a range of 15MHz by changing the water volume in the cavity from 0ml to 12ml. The system shows a magnetic field refocusing and enhancement with a considerable increase in penetration depth.

1579
Computer 146
Shunt, don't block: A New Approach to Dual Nuclear Coil Design.
Matthew George Erickson1

1MBI, U of Florida, Gainesville, FL, United States

Development of dual nuclear coils with high efficiency on both 1H and X remains a challenge.  The advent of hyperpolarized 13C imaging and hyperpolarized rare gas imaging has provided impetus for developing such a coil.  In this work, we report prototype 1H/13C surface coil that makes use of tune/match circuits augmented by high performance shunt notch filters constructed from hybrid transmission line circuits.  In this design, all conductive elements in the utility region are simultaneously resonant with high efficiency on both 1H and X.  The design may be extended to both volume and array coils for most 1H/X pairs.

1580
Computer 147
A triple tuned coil and front-end for simultaneous multinuclear MR imaging and spectroscopy
Chung-Huan Huang1, Hongli Dong2, Stephen E. Ogier2, Chenhao Sun2, and Steven M. Wright2

1Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States, 2Texas A&M University, College Station, TX, United States

There are several ways to implement simultaneous acquisition for multiple nuclei. A single-port triple tuned coil is the simplest structure and has the best potential for integration into multiband arrays. This abstract demonstrates an approach to acquire three nuclei (1H/23Na/2H) MRS simultaneously by using a home-built broadband spectrometer with a triple tuned coil. The broadband spectrometer front-end is capable of providing separate gains to each of studied nucleus where signal sensitivity variation is large and can reduce data throughput load by using undersampling techniques while still maintaining similar performance as a Varian Inova system.

1581
Computer 148
Interactive hand gestures for HoloLens rendering control of real-time MR images
Andrew Dupuis1,2, Dominique Franson1, Nicole Seiberlich1, and Mark A Griswold1,2,3

1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 2Interactive Commons, Case Western Reserve University, Cleveland, OH, United States, 3Department of Radiology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States

User interactions via hand gestures are added to a real-time data acquisition, image reconstruction, and mixed-reality display system to allow a user to interact more flexibly with the rendering. Images at precalibrated slice locations are acquired and displayed in real-time to the user, who is able to toggle between viewing some or many slices as well rotate, resize, and dynamically adjust the window and level of the rendering. 

1582
Computer 149
Dynamic Dual Frequency Transmit and Receive Coil Pair for Development of a New Open MRI System
Charles Rogers III1, Gigi Galiana1, and Todd Constable1

1Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States

We present progress on development and testing of a two-coil array with each coil separately and dynamically tunable between dual frequencies.  This test setup works toward the goal of developing a larger nine-element coil array for a new style of open MRI system utilizing the Bloch-Siegert shift at low Bo field. The array design is such that pairs of coils are selected for transmission at ~850kHz while allowing simultaneous receive at ~1MHz on the non transmitting coils.  We discuss the construction and present measurements of RF scattering parameters of a two-coil test setup.

1583
Computer 150
A highly-miniaturized inverted cable trap
Xinqiang Yan1,2 and John C. Gore1,2

1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Radiology and Radiological Science, Vanderbilt University, Nashville, TN, United States

Cable traps are commonly used for RF coils to suppress the common-mode current flowing on the outer conductor of coaxial cables. In massive-element array coils, conventional cable traps become cumbersome and not easy to assemble due to the limited space. In this work, we propose a novel circuit component called an “inverted cable trap”, which uses the outer conductor of a coaxial cable to form a capacitor rather than an inductor and which can be highly miniaturized. This inverted trap suppresses common-mode signals by up to -23 dB at 300 MHz which makes it valuable for operations at 7T.


MR System, Characterization & Tuneup

Exhibition Hall
Monday 9:15 - 10:15
 Engineering

1584
Computer 151
MR to pseudo CT conversion:  Combining Deep-Learning and Analytical Image Processing
Florian Wiesinger1, Sandeep Kaushik2, Mathias Engström3, Pauline Hinault4,5, Andrew Leynes6, Mikael Bylund7, David Gensanne8, Tufve Nyholm7, Peder Larson6, and Cristina Cozzini1

1GE Healthcare, Munich, Germany, 2GE Global Research, Bangalore, India, 3GE Healthcare, Stockholm, Sweden, 4LITIS, Rouen, France, 5GE Healthcare, Paris, France, 6Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 7Umeå University, Umea, Sweden, 8Centre Henri Becquerel, Rouen, France

Here we present an improved method for ZTE to pseudo CT conversion by combining an analytical signal model (i.e. ZTE to CT signal scaling) with Connected Component Analysis (CCA) and Deep Learning (DL) based air vs. bone discrimination.  The method is demonstrated for the two main anatomical regions (head&neck and pelvis) and the two main field strengths (1.5T and 3T) of interest.

1585
Computer 152
First MRI of the human spinal cord at 9.4T
Ole Geldschläger1, Saipavitra Murali Manohar1, Andrew Wright1, Nikolai Avdievitch1, and Anke Henning1

1Hochfeld-Magnetresonanz, Max-Planck-Institut für biologische Kybernetik, Tübingen, Germany

This study presents the first anatomical images of the human cervical spinal cord recorded at the ultrahigh field strengths of 9.4 T. The images were acquired with a Gradient-Echo-Sequence. Different sequence parameters and resolutions were compared. The highest in-plane resolution was 0.2 mm x 0.2 mm. These high-resolution images show the details of the spinal cord and the surrounding tissue clearly. All measurements were acquired with an 8-channel transmit-, 16-channel receive-tight-fit array coil, originally dedicated for brain applications.

1586
Computer 153
An generalized single MR image super resolution approach using combined super-resolution network and cycle-consistent adversarial network
Botian Xu1,2, Yaqiong Chai1,2, Kangning Zhang3, Natasha Lepore1,2, and John Wood1,2

1Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States, 2Children's Hospital Los Angeles, Los Angeles, CA, United States, 3Department of Electrical and Computer Engineering, University of California, Davis, Davis, CA, United States

Traditional inception-based convolutional neural networks (CNN) are proved to be capable of tackling high resolution image restoration, yet they are poor at generalization due to the supervised learning procedure. We proposed a combination of CNN-based super resolution network and generative adversarial network, to make full use of the learning of high resolution from CNN, as well as to improve the generalization of the network, by preserving the original contrast of the sequence. The result shows that our proposed network could perform MR super resolution across sequences with higher quality than that from a single CNN network. 

1587
Computer 154
Robust detection and potential application in orientation tracking of a small-amplitude field oscillation independent of location in the scanner bore and parallel to the static magnetic field.
Adam van Niekerk1, Andre van der Kouwe2,3, and Ernesta Meintjes1,4

1Human Biology, University of Cape Town, Cape Town, South Africa, 2Athinoula A. Martinos Center, Massachusetts General Hospital, Charlestown, MA, United States, 3Radiology, Harvard Medical School, Boston, MA, United States, 4Cape Universities Body Imaging Centre (CUBIC), University of Cape Town, Cape Town, South Africa

We explore the possible uses of a 40-kHz switching signal that is proportional to the gradient slew rate. The signal was identified by probing the rate of change of the magnetic flux density in the MRI scanner using a three-dimensional pickup coil. The signal is independent of both the orientation of the pickup coil and location in the scanner bore, and is directed parallel to the static magnetic field. This indicates that it is not caused by current in the gradient coils. These properties make this signal a useful vector reference that could be used for orientation tracking or time frame synchronisation.

1588
Computer 155
FPGA-based coprocessor for real-time SENSE reconstruction: Design and Implementation
Abdul Basit1, Omair Inam1, and Hammad Omer1

1Electrical Engineering, COMSATS University Islamabad, Islamabad, Pakistan

In real-time clinical settings, high speed systems have become imperative to meet the large data processing requirements of parallel MRI algorithms e.g. SENSE. Field-Programmable-Gate-Arrays (FPGAs) have recently emerged as a viable solution to adhere the rising demands of fast data processing by exploiting the inherent parallelism of SENSE reconstruction algorithm. This paper presents the first design effort to implement high performance 32-bit floating-point FPGA-based coprocessor for real-time SENSE reconstruction using high-level-synthesis (HLS) frame work. In-vivo results of 8-channel 1.5T human-head dataset show that the proposed system speeds up the image reconstruction time up to 1000x without compromising the image quality.

1589
Computer 156
Circumventing Radiation Beam and RF-Coil Collisions in a Rotating B0 Linac-MR Hybrid using a Three-channel Array
Vyacheslav Volotovskyy1, Radim Barta2, Keith Wachowicz1,2, Nicola De Zanche1,2, and B. Gino Fallone1,2

1Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada, 2Oncology, Division of Medical Physics, University of Alberta, Edmonton, AB, Canada

Hybrid radiation therapy and magnetic resonance imaging (MRI) systems are providing new options for cancer therapy. In our design the B0 rotates on a gantry along with the linear accelerator (linac) for treatment delivery. This introduces new challenges to RF-coil design as the plane of MR precession changes depending on gantry angle. Our three channel array is appropriate for the head and consists of two butterfly coils and a circular loop. The array provides equal SNR at all gantry angles while allowing a radiation window to avoid collisions between the radiation beam and the RF-coils.

1590
Computer 157
Designing a multichannel TMS/MRI system for 3 T: a 7-channel RF receive-only coil array prototype
Lucia I. Navarro de Lara1,2, Anthony Mascarenas3, Douglas Paulson3, Sergey Makarov4, Jason P. Stockmann1,2, Lawrence L. Wald1,2, and Aapo Nummenmaa1,2

1Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 2Radiology, Harvard Medical School, Boston, MA, United States, 3Tristan Technologies, San Diego, CA, United States, 4Department of Electrical and Computer Engineering, Worcester Polytechnic Institute, Worcester, MA, United States

An integrated multichannel TMS/MRI head coil array for 3T is currently under development to enable electronically controlled multifocal TMS with concurrent whole-head fMRI. To test the feasibility of the proposed RF hardware design, a 7-channel RF receive-only coil array prototype was built. Calculated B+1 maps showed the attenuating effect of the TMS coil on the transmit field.  The improvement by retuning the affected RF loops was demonstrated using MPRAGE images. Functional images showed no additional artefacts when TMS pulses were interleaved between the EPI volumes. The prototype results support our RF hardware design approach for the TMS/MRI system.

1591
Computer 158
3D Printed Mouse Brain Holders for High Throughput Ex Vivo MRI
Dong Kyu Kim1, Autumn R Greenfield1, and Mark D Does1,2,3

1Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University Institute of Imaging Sciences, Vanderbilt University, Nashville, TN, United States, 3Department of Electrical Engineering, Vanderbilt University, Nashville, TN, United States

High throughput MRI of ex vivo mouse brains has been established as a powerful tool for studying mouse models of neurological disorders. These studies have used a RF coil array to image up to 16 mouse brains simultaneously; however, most pre-clinical MRI facilities are not equipped with multiple receivers and may not have a high field magnet with sufficient bore size to accommodate multiple coils. Here, we present designs for 3D-printed multiple mouse brain holders that can be produced inexpensively and enable high quality multiple mouse brain MRI with RF coils ≥ 25 mm diameter. 

1592
Computer 159
Preliminary Investigation of the Vibration Characteristics and Isolation Requirements of a Prototype MRI Scanner
Genevieve Rodrigue1 and Chris K. Mechefske1

1Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada

A persistent issue with MRI scanners is inadequate vibration isolation. The objective of this work is to implement vibration isolation in a prototype MRI scanner base to minimize stringent and costly structural requirements for MRI suites. To first use a computational model of an MRI base as an analysis tool, modal analysis has been conducted to validate the model. Furthermore, analysis of a pneumatic isolator has been completed to assess its suitability to the MRI application. Testing demonstrated adequate performance of the isolator under most expected loading cases. Computational analysis of an idealized isolator model supports the experimental results.

1593
Computer 160
Plastic Bricks in MRI: An Efficient Way to Build Static and Dynamic Phantoms
Nick Scholand1, Sebastian Rosenzweig1, Felix Ertingshausen1, and Martin Uecker1

1Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany

Novel MRI techniques are typically tested on phantoms, hence static and dynamic phantom setups are required during development. However, MRI phantoms are either off-the-shelf components which are expensive and not very flexible or are custom-built which is time-consuming and often requires specialized equipment. Here we report our experience using plastic bricks to build a variety of static and dynamic phantoms.

1594
Computer 161
A method for suppressing simultaneous multi-slice (SMS) imaging artifacts caused by RF distortions
Yuan Zheng1, Yu Ding1, Qing Wei2, Rongxing Zhang2, and Weiguo Zhang1

1UIH America, Houston, TX, United States, 2United Imaging Healthcare, Shanghai, China

In simultaneous multi-slice (SMS) imaging, the multi-band RF pulses have complicated waveforms and may suffer from distortions, which can cause sideband excitations and result in image artifacts. We have proposed a simple method for correcting the RF distortions using a prescan of the RF output, which can be conveniently integrated in general SMS applications to suppress such artifacts with a negligible increase of scan time.

1595
Computer 162
A 3T MRI platform for imaging rodent models by integrating a dedicated high-strength gradient coil on a whole-body magnet
Sheng-Min Huang1,2, Kuan-Hung Cho1, Ming-Jye Chen1, Hsuan-Han Chiang1, Chang-Hoon Choi3, Richard Buschbeck3, Ezequiel Farrher3, N. Jon Shah3,4,5,6, Ruslan Garipov7, Ching-Ping Chang8, Hsu Chang1, and Li-Wei Kuo1,9

1Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan, 2Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, 3Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany, 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, 7MR Solutions Ltd., Guildford, United Kingdom, 8Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan, 9Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan

In this study, a high-strength gradient coil dedicated for imaging rodent models has been successfully integrated on a whole-body 3T MRI magnet. The imaging capability of this system has been qualitatively and quantitatively demonstrated using phantom, ex-vivo specimen and in-vivo rat experiments. Since the hardware components used for integration on our system are independent from system vendors, this study can be a practically useful guide, especially for those who want to conduct small animal imaging on clinically used magnets.

1596
Computer 163
Solid material resembling human tissues:a white and gray matter brain phantom.
Manuel Alejandro Chapa1,2,3, Hernán Valenzuela4, Cristán Montalba2,3,5, Sergio Uribe2,3,5, Macelo Andia2,3,5, Flavia Zacconi4, and Cristán Tejos1,2,3

1Department of Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 2Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 3Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile, 4Faculty of Chemistry, Deparment of Organic Chemistry, Pontificia Universidad Católica de Chile, Santiago, Chile, 5Department of Radiology, Pontificia Universidad Católica de Chile, Santiago, Chile

In this work we present a solid brain phantom that resemble the anatomy and T2 relaxation times of the brain. The developed material is a 3-component mix. Adjusting the relative concentration of the compounds allow to modulate T2 relaxation time, following a linear relationship within a range of 145 to 263ms. The resulting solid phantom can reproduce correctly the geometry of white and gray matter. The range of achievable T2 relaxation times makes possible the construction of phantoms that could mimic a wide range of biological tissues. 

1597
Computer 164
Rapid Material Characterization For 3D-printed MRI Coils: A Deep Learning Approach
Bahareh Behzadnezhad1,2, Nader Behdad1, and Alan B. McMillan2,3

1Electrical Engineering, University of Wisconsin-Madison, Madison, WI, United States, 2Radiology, University of Wisconsin-Madison, Madison, WI, United States, 3Medical Physics, University of Wisconsin-Madison, Madison, WI, United States

A novel material characterization approach which is based on a microstrip line test fixture paired with deep learning analysis, is presented to optimize the use of additive manufacturing (3D-printing) in constructing the structure of MRI coils with arbitrary 3D geometries. This type of manufacturing is appealing because it can be used to construct geometries that are time-consuming and expensive to make using traditional machining methods. Full-wave electromagnetic simulations are efficient and promising technique to expedite the design process of MRI coils and therefore, it is crucial to include the electrical properties of 3D-printed materials in the electromagnetic simulations because it affects coil performance. 

1598
Computer 165
MR thermometry guided RF hyperthermia in the head and neck region – does the new MRcollar affect the imaging?
Kemal Sumser1, Tomas Drizdal1,2, Juan Antonio Hernandez-Tamames3, Gerard Cornelis van Rhoon1, Gennaro G. Bellizzi1, and Margarethus Marius Paulides1,4

1Department of Radiation Oncology, Erasmus MC - Cancer Institute, Rotterdam, Netherlands, 2Faculty of Biomedical Engineering, Czech Technical University in Prague, Prague, Czech Republic, 3Department of Radiology, Erasmus MC, Rotterdam, Netherlands, 4Department of Electrical Engineering, Technical University of Eindhoven, Eindhoven, Netherlands

Clinical studies established that adjuvant effect of mild hyperthermia can be improved by increasing thermal dose, which  can be improved by online 3D dosimetry. To take advantage of MR thermometry, we developed an MR compatible head and neck RF hyperthermia applicator prototype for the head and neck region: the MRcollar. To establish the impact of the MRcollar on image quality, we imaged  B1+ map and calculated the Signal-to-Noise Ratio when the body coil was used.

1599
Computer 166
A Frequency Selective RF Shield for MR Guided Thermal Therapies at 3T
Rock Hadley1, Dylan Palomino1, Robb Merrill1, Dennis L. Parker1, and Charles Anderson2

1Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2NeoTherma Oncology Inc., Wichita, KS, United States

A proof of concept, a passive frequency selective RF shield was designed and constructed to block a single frequency (13.56 MHz) from passing through the shield. S21 and phantom SNR measurements demonstrate near transparency to the 123 MHz imaging frequency.

1600
Computer 167
High Resolution PWM Generation for High Frequency Switching Gradient Amplifier Control
Volkan Acikel1, Aylin Dogan1, Filiz Ece Filci1, Gokhan Cansiz1, and Ergin Atalar2,3

1Aselsan A.S., Ankara, Turkey, 2Electrical-Electronics Engineering, Bilkent Universitesi, Ankara, Turkey, 3National Magnetic Resonance Center, Bilkent Universitesi, Ankara, Turkey

Recently gradient array systems draw attention of researchers with their capabilities.  However, it is crucial to drive all array elements as desired to be able to spoil all the advantages of the gradient array.  In terms of adjusting the timing of the gradient pulses, generating pulse width modulation (PWM) signals from one source, i.e. a single FPGA, for all array amplifiers would be a good solution. However, required number of bits to generate PWM signal would be limited to clock frequency. In this abstract, required digital resolution to generate PWM signals is analyzed and a method to generate PWM signals with resolution less than  using I/O delay (IODELAY) elements of virtex7 family FPGA is presented. 

1601
Computer 168
A High Duty Cycle, Multi-channel, RF Power Amplifier for High Resolution TRASE MRI
Aaron Purchase1, Tadeus Palasz2, Hongwei Sun1, Jonathan Sharp1, and Boguslaw Tomanek1

1Department of Oncology, University of Alberta, Edmonton, AB, Canada, 2Department of Physics, Jagiellonian University, Krakow, Poland

A radiofrequency (RF) power amplifier is an essential component of any MRI system. Unfortunately, no commercial amplifier exists to fulfill the needs of the transmit array spatial encoding (TRASE) technique, requiring minimum 50% duty cycle, high output power 1 kW and independently controlled multi-channel capability. Hence a home-made dual channel RF power amplifier dedicated for TRASE at 0.22 T (9.27 MHz) was made using commercially available components. High spatial resolution one-dimensional TRASE was obtained with the power amplifier to demonstrate its capability. The results were compared with the commercial amplifiers, Analogic AN8110 and TOMCO BT00500, exceeding performance considering electronic noise and duty cycle.

1602
Computer 169
A Novel Asymmetric 16-Element pTx Transceiver Coil Array: Towards Denser Elements for Improved RF-Shimming and G-Factor for Parallel Cardiac MRI in Pigs at 7T
Ibrahim A. Elabyad1, M. Terekhov1, M. R. Stefanescu1, D. Lohr1, M. Fischer1, and L. M. Schreiber1

1Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Wuerzburg, Wuerzburg, Germany

A novel 8Tx/16Rx coil array was designed, simulated, and tested in phantom and for cardiac magnetic resonance imaging (cMRI) ex-vivo pigs at 7T. The 16-elements of the array were distributed on a half-elliptical shape housing. Combined signal-to-noise ratio (SNR) maps and FA-maps were acquired using the developed coil before and after RF-shimming. The novel cardiac array supports parallel imaging with acceleration factors of up to R=4 without a significant degradation in the image quality. High-resolution ex-vivo cardiac images were acquired with 0.3mm x 0.3mm in plane resolution. The dedicated coil enhances the SNR within the heart by about six-times compared to a commercial human cardiac coil array.

1603
Computer 170
Highly decoupled shielded loop coils as receive array elements for 7T MRI
Irena Zivkovic1, Thomas Ruytenberg1, and Andrew Webb1

1Radiology Department, C.J. Gorter Center for High Field MRI, Leiden, Netherlands

We propose a shielded loop coil design for operation as a receive array element at 7T. The proposed coil geometry provides high decoupling between adjacent and non-adjacent loop elements without overlapping or preamplifier decoupling.  A four-coil receive array was constructed for high resolution imaging of the knee at 7T. The coil coupling between the elements  for in-vivo measurements was lower than -26 dB. Images with an isotropic resolution of 0.7 x 0.7 x 0.7 mm were acquired in five minutes.



1604
Computer 171
Optimization of the degenerate birdcage transmit array coil for minimum coupling
Ehsan Kazemivalipour1,2, Alireza Sadeghi-Tarakameh1,2, and Ergin Atalar1,2

1Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey

This abstract introduced a methodology to minimize the magnetic coupling between non-adjacent channels in a degenerate birdcage transmit array coil (DBC) by optimizing some of its physical parameters. The method is based on minimization of the mutual-inductances normalized by the self-inductances. Optimum radius, length in the z-direction, the width of end-rings, and the width of rungs are found for a 3T shielded twelve-channel head DBC with capacitive decoupled loops. Finite element based simulation results confirmed the validity of the results.


1605
Computer 172
Optimization of Phase Presets of Multi-Channel Transceiver Arrays for 7T Cardiac MRI
Maxim Terekhov1, Ibrahim A. Elabyad1, Maria R. Stefanescu1, David Lohr1, and Laura Maria Schreiber1

1Chair of Cellular and Molecular Imaging, Comprehensive Heart Failure Center, University Hospital Wuerzburg, Wuerzburg, Germany

Multiple-element transmit (mTx) phased array technology provides significant improvement of the B1+-field homogeneity in ultra-high field (B0≥7T) cardiac MRI (cMRI). We propose time efficient semi-combinatorial approach of finding optimal Tx-elements phases presets. The proposed technique allows for searching the transmitter phases providing absolute optimum for а targeted B1+-field cost functions using high redundancy of optimal phase vector space. The technique was tested for pre-phasing of the in-house-built mTX-arrays  in pigs at  7T cMRI. Improvement of the B1+-field homogeneity of >100% and SNR gain >50% was achieved using 10% of the computation time needed when compared with brute-force optimization.

1606
Computer 173
The double-tuned floating cable trap: design and first results
Martin Vít1,2,3, Jürgen Sieg1, Michael Pichler1, Sigrun Goluch-Roat1, Daniel Jirák2,3, and Elmar Laistler1

1Division MR Physics, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria, Wien, Austria, 2IKEM (Institute for Clinical and Experimental Medicine), Vídeňská 1958/9, 140 21 Praha 4, Czech Republic, Praha, Czech Republic, 3TUL (Technical University of Liberec), Studentská 1402/2,461 17 Liberec, Czech Republic, Liberec, Czech Republic

We present a new design for a double-resonant floating cable trap that consists of two nested floating traps suppressing common mode currents at two frequencies simultaneously. An implementation for 1H and 31P at 7 Tesla is presented and its properties are investigated on the bench.

1607
Computer 174
A “Less-for-More” Concept in Array Coil Design
Tsinghua Zheng1, Xiaoyu Yang1, Haoqing Zhu1, and Yong Wu1

1Quality Electrodynamics, LLC, Mayfield Village, OH, United States

We present a novel “Less-for-More” concept for array coil by joining different coils as one RF channel with transmission lines. This concept not only simplifies the coil design but also achieves optimum isolation among all channels by overlapping. A 4-ch 8-loop knee coil at 1.5T was constructed to demonstrate this concept. The test result shows similar signal-to-noise ratio (SNR) at the center to a commercial 1.5T 15-channel Tx/Rx knee coil’s. Furthermore, additional acceleration at g factor 2 in SI direction is also achieved with a 4-ch only coil besides axial accelerations.

1608
Computer 175
Design of a 12-channel rhesus head coil array for functional MRI at 3 T
Zidong Wei1, Qiaoyan Chen 2, Hai Lu1, Xiangming Hou1, Qiang He1, Xiaoliang Zhang3,4, Xin Liu2, Hairong Zheng2, and Ye Li2

1Shanghai United Imaging Healthcare, Shanghai, China, 2Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 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

In this work, a 12-channel rhesus head coil array for functional magnetic resonance imaging (fMRI) was designed, constructed and evaluated by imaging experiments in phantom studies and in-vivo studies. Compared to a commercially available 12-channel knee coil, the proposed 12-channel rhesus head coil provides improved performance not only in SNR and parallel imaging capability, but also in temporal SNR (tSNR) in resting-state fMRI studies.


Prostate MRI: Technical Developments

Exhibition Hall
Monday 13:45 - 14:45
 Body: Breast, Chest, Abdomen, Pelvis

1609
Computer 1
The Use of Relaxation Maps from Synthetic MRI in Differential Diagnosis of Prostate Cancer
Yadong Cui1,2, Yue Lin1,2, Chunmei Li1, Jianxun Qu3, Bing Wu3, and Min Chen1,2

1Department of Radiology, Beijing Hospital, National Center of Gerontology, Beijing, China, 2Graduate School of Peking Union Medical College, Beijing, China, 3GE Healthcare, Beijing, China

Synthetic MRI enables absolute quantification of T1, T2 and (proton density) PD value. The aim of the study was to primarily evaluate the feasibility of synthetic MRI in differential diagnosis of (prostate cancer) PCa. We analyzed 18 PCa lesions in 14 PCa patients, 26 SH (stromal hyperplasia), 25 GH (glandular hyperplasia) nodules and 21 prostatitis areas in 22 non-PCa patients who underwent multi-parameter MRI before needle biopsy. T1WI, T2WI, DWI and MAGiC (magnetic resonance image compilation) sequences were acquired respectively. Our results showed the T1 and T2 value of PCa lesion was significantly lower than GH nodule and prostatitis area. The PD value of PCa lesion was significantly lower than GH nodule. We concluded that synthetic MRI was helpful for differential diagnosis of PCa.

1610
Computer 2
Two exploratory radiomics segmentation algorithms in T2-weighted imaging analysis for predicting apical positive surgical margins of prostate cancer: A pilot study
Xiang Liu1, Shuai Ma1, Xiaodong Zhang1, and Xiaoying Wang1

1Peking University First Hospital, Beijing, China

SynopsisThis retrospective study aims to compare the two different segmentation algorithms of radiomics analysis for predicting the apical surgical margin (SM) status before radical prostatectomy (RP). Preoperative prostate MR scans were performed for 76 enrolled patients and T2-weighted images was assessed by a radiomics model, using two different delineating methods: including the surrounding tissues of the targeted lesions or not. Finally 152 bilateral surgical margins’ status (training dataset: n = 110, testing dataset: n = 38) were evaluated. The result demonstrated the segmentation algorithms were comparable, of which the new method might reduce the delineation work for future radiomics research.

1611
Computer 3
Test-retest repeatability of ADC measurements using MUSE: Evaluation in phantoms and prostate
Fuad Nurili1, Maggie Fung1, Yulia Lakhman1, Ricardo Otazo1, David Yusupov1, Elena Kaye1, Oguz Akin1, and Yousef Mazaheri1

1Memorial Sloan Kettering Cancer Center, New York, NY, United States

In this study, we evaluated the repeatability of multiplexed sensitivity-encoding (MUSE) DW-EPI apparent diffusion coefficient measurements (ADC) in phantom and prostate images. High quality test-retest prostate and phantom ADC maps obtained from phantom and volunteer studies measured values using MUSE (2-4 interleaves) were within 1.4-4.7% (phantom) and 3.2-14.7% (prostate) of one another. In comparison, test-retest repeatability results for standard single-shot EPI (acceleration factor=2) were 4.5-9.4% (phantom) and 15.2-19.2% (prostate). MUSE images exhibit reduced geometric distortion.

1612
Computer 4
A Fully Automatic Blind Estimation of Tumor Microvascular Permeability using Embedded Unsupervised Regularizations based on Prostate DCE-MRI
Junjie Wu1, Ya Cao1, Xiaodong Zhang2, Xiaoying Wang2, and Jue Zhang1

1Peking University, Beijing, China, 2Peking University First Hospital, Beijing, China

Vascular permeability can reflect tumorigenesis and metastasis. Previous dynamic contrast-enhanced magnetic resonance imaging based pharmacokinetic parameters estimation needs to manually select arterial input function (AIF) or reference regions (RR), and the results depend sensitively on the AIF selection. Our goal is to develop a more robust estimation approach without previously provided AIF or RR regions, for examining bone metastases from prostate cancer.

1613
Computer 5
Comparison of 12 different constructs of pre-trained convolutional encoders for semantic segmentation in prostate brachytherapy MRI
Jeremiah Wayne Sanders1, Steven Frank2, Gary Lewis3, and Jingfei Ma1

1Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, TX, United States, 2Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, United States, 3Radiation Oncology, University of Texas Medical Branch, Galveston, TX, United States

Anatomy contouring is essential in quantifying the dose delivered to the prostate and surrounding anatomy after low-dose-rate prostate brachytherapy. Currently, five anatomical structures including the prostate, rectum, seminal vesicles, external urinary sphincter, and bladder, are contoured manually by a radiation oncologist. In this work, we investigated six convolutional encoder-decoder networks for automatic segmentation of the five organs. Six pretrained convolutional encoders and two loss functions were investigated. This yielded twelve different models for comparison. Results indicated that classification accuracy of convolutional encoders pretrained on the ImageNet dataset positively correlated with semantic segmentation accuracy in prostate MRI.

1614
Computer 6
Object Recognition for Fully Automated Reference Tissue Normalization of T2-weighted MR Images of the Prostate
Mattijs Elschot1,2, Gabriel A Nketiah1, Mohammed RS Sunoqrot1, and Tone F Bathen1,2

1Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway, 2Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway

T2-weighted MRI, an integrated part of multi-parametric MRI for prostate cancer diagnostics, is indispensable for qualitative evaluation of prostate anomalies.  For quantitative assessment, however, normalization is necessary for comparison within and between patients. In this study, we developed and validated a fully automated object recognition method for multi-reference tissue normalization. The performance of the method was superior to existing fully automated normalization strategies, and the resulting pseudo T2 values were close to true T2 values from literature. The developed multi-reference tissue normalization method may thus improve the reproducibility and diagnostic performance of T2-weighted image features in future quantitative  applications.

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Application of hierarchical clustering to multi-parametric MR in prostate: Differentiation of tumor and normal tissue with high accuracy
Yuta Akamine1, Yu Ueda1, Yoshiko Ueno2, Takamichi Murakami3, Masami Yoneyama1, Makoto Obara1, and Marc Van Cauteren4

1Philips Japan, Tokyo, Japan, 2Department of Radiology, Kobe University Graduate School of Medicine, Hyogo, Japan, 3Department of Radiology, Kobe University Hospital, Hyogo, Japan, 4Asia Pacific, Philips Japan, Tokyo, Japan

Recently, machine learning (ML) or deep learning (DL) techniques has gain more attention for prostate cancer (PCa) detection. However, DL is often described as “black boxes” and difficult to explain results. In this study, hierarchical clustering (HC),an unsupervised ML technique, was applied to multi-parametric MR to differentiate PCa. DWI (IVIM and DKI) and permeability parameters were used for HC. Comparison of HC methods was conducted. We demonstrated that HC can accurately differentiate PCa and normal tissue (PZ: 97.5%, TZ: 95.7%), with an comparable to state-of-the-art D and K. Contrary to DL, HC produces results that can be interpreted (heatmaps).

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Optimized 3D Variable Flip Angle Fast Spin Echo: Simulating Different Prostate Tissue Types to Improve Contrast for Prostate Cancer Detection
Steven M Shea1,2

1Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States, 2Radiology, Loyola University Medical Center, Maywood, IL, United States

MRI of the prostate has become a crucial component of prostate cancer diagnosis. Most clinical sites use 2D FSE for T2 imaging. However, drawbacks exist and some institutions have moved to 3D using FSE-VFL. While groups have presented clinical results using FSE-VFL, none have published detailed investigations of different flip angle trajectories and parameter choices for maximizing lesion contrast in prostate cancer imaging. Flip angle trajectories were simulated for 3D FSE-VFL using T1 and T2 appropriate for prostate and then tested in a phantom. Overall, signal simulations proved useful for analyzing different parameters and flip angle trajectories for T2-weighted sequences.

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Computer aided diagnosis of prostate cancer in central gland using GOIA-sLASER 1H MRS
Neda Gholizadeh1, Peter B Greer1,2, John Simpson1,2, Peter Lau2,3, Arend Heerschap4, and Saadallah Ramadan1,3

1The University of Newcastle, Newcastle, Australia, 2Calvary Mater Newcastle, Newcastle, Australia, 3Hunter Medical Research Institute (HMRI), Newcastle, Australia, 4Radboud University Medical Center, Nijmegen, Nijmegen, Netherlands

The aim of the work described in this paper is twofold. First, evaluate the efficacy of the GOIA-sLASER magnetic resonance spectroscopic imaging (MRSI) using a 3T MRI scanner in detecting central gland prostate cancer with an external phased-array coil. Second, to develop risk predictor tools using a non-linear support vector machine (SVM) classification algorithm to analyse MRSI data. This research revealed a relatively high accuracy, sensitivity and specificity for pathological discrimination between normal vs cancer, low risk vs high risk cancer and low risk vs intermediate risk cancer using high quality prostate GOIA-sLASER MRSI.

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New three-parameter mathematical model for accurately fitting early enhancement of ultrafast dynamic contrast enhanced MRI to improve diagnosis of prostate cancer
Xiaobing Fan1, Aritrick Chatterjee1, Shiyang Wang1, Federico Pineda1, Ty O. Easley1, Aytekin Oto1, and Gregory S. Karczmar 1

1Radiology, University of Chicago, Chicago, IL, United States

Ultrafast DCE-MRI shows promise for detection of cancers. However, existing simple mathematical models do not have a smooth transition from baseline to early uptake phase and thus do not accurately model the early kinetics. Here we developed a new three-parameter model by combining a 4th-order rational and exponential function, namely REM (rational-exponential-model). Ultrafast prostate DCE-MRI was used to verify the accuracy of REM and compare the REM with two other models. The curvatures during initial enhancement and transition to washout were calculated. The REM characterized contrast agent kinetics for ultrafast DCE-MRI more accurately than previously developed models and thus improved diagnostic accuracy.

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Developments of Unet, Unet plus Conditional Random Field Insert, and Bayesian Vnet CNNs for Zonal Prostate Segmentation
Peng Cao1, Susan Noworolski1, Sage Kramer1, Valentina Pedoia1, Antonio Westphalen1, and Peder Larson1

1Department of Radiology, University of California at San Francisco, San Francisco, CA, United States

We studied 2d and 3d fully convolutional neural network for zonal prostate segmentation from T2 weighted MRI data. We also introduce a new methodology that combines Unet and conditional random field insert (CRFI) to improve the accuracy and robustness of the segmentation.

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Joint estimation of the field inhomogeneity and geometrical distortion for quantitative susceptibility mapping of the prostate
Reyhaneh Nosrati1,2, Wilfred W. Lam2, Ana Pejović-Milić1, and Greg J. Stanisz1,3

1Ryerson University, Toronto, ON, Canada, 2Sunnybrook Research Institute, Toronto, ON, Canada, 3University of Toronto, Toronto, ON, Canada

The geometrical distortions of MR images are potential source of error in MR-based radiation therapy planning (RTP) which requires accurate anatomical delineation. Beside the system-specific residual distortions, presence of any susceptibility-mismatch within the region of interest may lead to image distortion. We have recently proposed an algorithm based on quantitative susceptibility mapping (QSM) for post-implant dosimetry of prostate brachytherapy seeds. In this study, the undistorted field map in patients with and without implanted seeds was estimated and images were corrected accordingly, then QSM was performed. In patients with implanted seeds, distortion correction improved the accuracy of the QSM reconstruction.

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Variable Flip Angle T1 Consistency with and without Compensating for B1+ inhomogeneity in 3T Prostate MRI
Xinran Zhong1,2, Sepideh Shakeri1, Dapeng Liu1, James Sayre1, Steven S. Raman1, Holden H. Wu1,2, and Kyunghyun Sung1,2

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

Reliable pre-contrast T1 estimation is crucial for quantitative DCE MRI. Variable flip angle is widely used for pre-contrast T1 measurements and is sensitive to B1+ inhomogeneity. Although various B1+ techniques have been proposed, the application of B1+ compensation is not widely accepted yet. In this study, by evaluating T1 intra-scanner and inter-scanner consistency with and without B1+ compensation, we confirmed the necessity to perform B1+ compensation and a B1+ estimation method named reference region variable flip angle (RR-VFA) is recommended due to its consistent T1 estimation and wide availability.  

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A quality control system for automated prostate segmentation on T2-weighted MRI
Mohammed R. S. Sunoqrot1, Kirsten M. Selnæs1,2, Olmo Zavala-Romero3, Radka Stoyanova3, Tone F. Bathen1, and Mattijs Elschot1,2

1Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technolog, Trondheim, Norway, 2Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim, Norway, 3Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, FL, United States

Computer-aided detection and diagnosis (CAD) systems have the potential to improve robustness and efficiency compared to traditional radiological reading of MRI in prostate cancer. Fully automated segmentation of the prostate is a crucial step of CAD. With the advent of the deep learning-based (DL) methods in medical imaging, series of networks have been developed to segment the prostate.  Automated detection of poorly segmented cases would therefore be a useful supplement. Therefore, we proposed a quality control (QC) system to detect the cases that will result in poor prostate segmentation. The performance results shows that the proposed QC system is promising.

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Prostate cancer detection using an integrated slice-by-slice shimming acquisition scheme and three MR diffusion models: correlation with in-bore transperineal MR-guided biopsy
JIE BAO1, Xi-ming Wang1, Robert Grimm2, Alto Stemmer2, Zhong-shuai Zhang3, and Chun-hong Hu1

1The First Affiliated Hospital of Soochow University, suzhou, China, 2MR Application Development, Siemens Healthcare, Erlangen, Germany, Erlangen, Germany, 3MR Scientific Marketing, Siemens Healthcare, Shanghai, SHANG HAI, China

Multiparametric magnetic resonance imaging (mpMRI) of the prostate gland is increasingly being used in the setting of newly diagnosed disease to identify occult, higher-grade, or stage elements missed by conventional biopsy. In this study, a prototype diffusion weighted single shot EPI sequence with integrated slice-by-slice shimming (iShim) technique was applied to reduce the susceptibility artifacts of DW images[1]. Conventional mono-exponential DWI, intravoxel incoherent motion (IVIM), and diffusional kurtosis imaging (DKI) models were applied to preoperatively predict prostate cancer (PCa)[2, 3]. Our research showed that the diffusion coefficient in the peripheral zone, mean kurtosis, and the PSA level in the transition zone are potential predictive biomarkers for PCa.

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Automatic detection of prostate cancer lesion using various deep neural network in multi-parametric MRI combined including quantified parameters.
Jinseong Jang1, Jeong Kon Kim2, Subeom Park1, Won Tae Kim1, Shin Uk Kang1, Myung Jae Lee1, and Dongmin Kim1

1AI R&D Center, JLK Inspection, Seoul, Korea, Republic of, 2Department of Radiology, Asan Medical Center, Seoul, Korea, Republic of

we used qualitative and quantitative parametric MRI in various deep convolutional neural networks for fully-automatic detection of prostate cancer. region. various deep neural networks were compared with pathology map-based ground truth. The 3D convolutional neural networks achieved the highest performance in our experiments. 

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Use of kz-Space for Sub-mm Through-Plane Resolution in Multi-slice MRI: Application to Prostate
Soudabeh Kargar1,2, Eric A Borisch2, Adam T Froemming2, Roger C Grimm2, Akira Kawashima3, Bernard F King2, Eric G Stinson2, and Stephen J Riederer1,2

1Biomedical Engineering and Physiology, Mayo Graduate School, Rochester, MN, United States, 2Radiology, Mayo Clinic, Rochester, MN, United States, 3Radiology, Mayo Clinic, Scottsdale, AZ, United States

The goal of this work is to demonstrate sub-mm through-plane resolution in multislice T2SE MRI using kZ-space processing of overlapping slices and to show applicability in prostate MRI. Multiple overlapped slices are acquired and Fourier transformed in the slice-select direction. The slice profile is taken into account in the reconstruction using Tikhonov regularization. Sub-mm resolution is possible from 3.2mm thick slices. The method is applied to 16 consecutive subjects for whom prostate MRI was indicated. The in vivo results from prostate MRI show improved sharpness in the axial reconstructions when compared to the standard axial multislice method.

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Association of peri-prostatic adipose tissue (PPAT) and prostate cancer (PCa)
Qiong Ye1, Qi Zhang2, and Zhao Zhang1

1The Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China, 2The Department of Urology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China

The association between peri-prostatic adipose tissue (PPAT) and prostate volume (PV) was controversial in literatures. In our study, we adapted more reasonable definition of PPAT according to the observation during the surgery of radical prostatectomy (RP), and used histological finding from RP as reference, to explore the association between PPAT and PCa.

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Heterogeneous alternation of fat content of varied adipose deposits in prostate cancer patients
Qiong Ye1 and Zhao Zhang1

1The Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China

Prostate cancer (PCa) is characterized with dysregulated lipid metabolism. The function and fat content of adipose deposits varied with anatomical location. In our study, we explored the characteristic alternation of fat content of adipose tissues and muscle of pelvic region in prostate cancer (PCa) patients using mDixon.

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Assessment of the prostate cancer with HyperCube T2-weighted imaging
Motoyuki Katayama1, Takayuki Masui1, Kazuma Terauchi1, Mitsuteru Tsuchiya1, Masako Sasaki1, Kenshi Katayama1, Takahiro Yamada1, and Mitsuharu Miyoshi2

1Seirei Hamamatsu General Hospital, Hamamatsu, Japan, 2GE Healthcare Lapan, Hino, Japan

We compare delineation of prostate cancers in HyperCube T2WI with those in conventional T2WI using PIRADS. HyperCube 3D T2WI can provide useful information about prostate cancer, and contribute to the PI-RADS.

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Radiomics based on Multiparametric MRI for Predicting Upgrading of Prostate Cancer from Biopsy to Radical Prostatectomy
Gumuyang Zhang1, Yuqi Han2,3, Jingwei Wei3, Yafei Qi1, Dongsheng Gu3, Jing Lei1, Yu Xiao1, Weigang Yan1, Huadan Xue1, Feng Feng1, Hao Sun1, Zhengyu Jin1, and Jie Tian3

1Peking Union Medical College Hospital, Beijing, China, 2School of Life Science and Technology, Xidian University, Xi'an, China, 3Key Laboratory of Molecular Imaging, Institute of Automation, Chinese Academy of Sciences, Beijing, China

The disparity of biopsy Gleason score of prostate cancer (PCa) with that of the corresponding radical prostatectomy (RP) remains an unsolved problem. We developed and validated radiomics model based on T2-weighted, fat-suppressed T2W, apparent diffusion coefficient and dynamic contrast enhancement images to predict upgrading from biopsy to RP. The radiomics model achieved the area under the curve values of 0.977 and 0.931 for the training and validation cohorts, and outperformed the clinical model combining clinical stage and time from biopsy to RP. The radiomics model could serve as a non-invasive tool for individualized prediction of upgrading of PCa.

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MR Fingerprinting and Diffusion Mapping based Neural Network Classifier for significant prostate cancer characterization in Peripheral Zone and Transition Zone
Kun Yang1, Ananya Panda2, Verena Carola Obmann3,4, Jesse Hamilton1, Katie Wright3, and Vikas Gulani1,3

1BME, Case Western Reserve University, Cleveland, OH, United States, 2Radiology, Mayo Clinic, Rochester, MN, United States, 3Radiology, Case Western Reserve University, Cleveland, OH, United States, 4Department of Diagnostic, Interventional and Pediatric Radiology, Inselspital, Bern, Switzerland

This study demonstrates the utility of a neural network classifier in separating significant cancer from low-grade cancer and non-cancerous lesions, based on the quantitative MRF and diffusion mapping. Using targeted biopsy data for training, the neural network classifier outperforms the linear regression model in both peripheral zone (PZ) and transition zone (TZ). The differentiation results showed an AUC of 0.90 in PZ and AUC of 0.89 in the TZ, comparing to AUC of 0.86 and 0.81 using Logistic Regression respectively. After applying the adaptive data oversampling algorithm, the AUC in characterizing TZ lesions can reach 0.96. Further classification utilizing patient clinical information showed statistically better accuracy in PZ while worse in TZ.

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Classification of prostate cancer by radiomics
Jing Zhang1, Yu-dong Zhang2, Yang Song1, Xu Yan3, and Guang Yang1

1East China normal university, Shanghai, China, 2Jiangsu Province Hospital, Jiangsu, China, 3MR Scientific Marketing, Siemens Healthcare, shanghai, China

Timely diagnosis and treatment could effectively reduce patient risk for clinical significant prostate cancer (PCa). In this abstract, we extracted 327 quantitative features from prostate mp-MRI images, then we used a homemade open-source tool named Feature Explorer to study combinations of radiomics algorithms and hyper-parameters in order to find the best model for classification of PCa into non-clinical–significant and clinical significant. We obtained a candidate model with AUC of 0.823, accuracy of 0.827. Four features selected for classification are easily understandable in the sense of image characteristics. Feature Explorer was demonstrated to be an efficient tool for radiomics studies.

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Quantitative comparison of luminal water imaging with DWI for characterization of prostate cancer aggressiveness: early experience
Stefanie Hectors1,2, Daniela Said1,2, Jeffrey Gnerre1,2, Ashutosh Tewari3, and Bachir Taouli1,2

1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, United States

Luminal water imaging (LWI) is an emerging technique for noninvasive characterization of prostate cancer (PCa) aggressiveness. The goal of our ongoing study is to compare the diagnostic performance of LWI to DWI for assessment of PCa aggressiveness. We observed that the luminal water fraction (LWF) from LWI showed high diagnostic performance for differentiation between Grade Group (GG) 2 (i.e. Gleason 3+4) and GG 3 and higher (i.e. Gleason 4+3 and higher) cancers (AUC=0.86), while ADC showed an AUC of 0.62. These initial results suggest additional value of LWI for PCa characterization, which will be verified in a larger cohort. 

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A 3D convolutional neural network for diagnosing prostate cancer using volumetric T2-weighted MRI.
Pritesh Mehta1, Michela Antonelli1, Shonit Punwani2, and Sebastien Ourselin3

1Biomedical Engineering and Medical Physics, University College London, London, United Kingdom, 2UCL Centre for Medical Imaging, University College London, London, United Kingdom, 3School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom

In this work, we designed and evaluated a convolutional neural network for prostate cancer diagnosis using volumetric T2-weighted MRI. Our key contribution is a 3D implementation of a residual network (ResNet), optimised to perform a classification between patients with prostate cancer and patients with benign conditions. On this task, cross-validation on a dataset consisting of 240 patients, produced a mean area under the receiver operating characteristic curve of 0.78, which was on par with an experienced radiologist.


Emerging Technologies in Body Imaging

Exhibition Hall
Monday 13:45 - 14:45
 Body: Breast, Chest, Abdomen, Pelvis

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Noise Reduction in Prostate Single-Shot DW-EPI utilizing Compressed SENSE Framework
Masami Yoneyama1, Kosuke Morita2, Johannes Peeters3, Takeshi Nakaura4, and Marc Van Cauteren5

1Philips Japan, Tokyo, Japan, 2Kumamoto University Hospital, Kumamoto, Japan, 3Philips Healthcare, Best, Netherlands, 4Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan, 5Philips Healthcare, Tokyo, Japan

DWI is a key component of the prostate MRI examination, but current prostate DWI images have limited resolution. Small-FOV DWI with SENSE often suffers from increased noise artifacts. We attempt to utilize a combination of parallel imaging and compressed sensing technique (C-SENSE) framework for reducing the noise artifacts in single-shot DW-EPI images (EPI with C-SENSE: EPICS). EPICS clearly reduces noise-like artifacts and significantly improves the accuracy and robustness of ADC values in small FOV high b-value prostate DWI compared with conventional SENSE DW-EPI, without any penalty for scan parameters. 

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Hyperpolarized 129Xe dissolved-phase MR detects physiological changes in human lungs after low-dose inhaled lipopolysaccharide challenge
Agilo L Kern1,2, Filip Klimes1,2, Andreas Voskrebenzev1,2, Marcel Gutberlet1,2, Heike Biller2,3, Julius Renne1,2, Olaf Holz2,3, Frank Wacker1,2, Jens M Hohlfeld2,3,4, and Jens Vogel-Claussen1,2

1Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany, 2Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany, 3Department of Clinical Airway Research, Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany, 4Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany

Low-dose inhalation of lipopolysaccharide (LPS) provides a disease model in humans for development of anti-inflammatory drugs but sensitive methods for assessment of the inflammatory response to LPS are lacking. The feasibility of hyperpolarized 129Xe dissolved-phase imaging and chemical shift saturation recovery (CSSR) was investigated in this setting. The ratio of 129Xe in red blood cells and in tissue/plasma was found to decrease and the capillary transit time derived from CSSR was found to increase after LPS inhalation. These effects are attributed to pulmonary edema and vasodilation. In conclusion, hyperpolarized 129Xe MR is sensitive even for low-dose LPS challenges in humans.

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Motion-Corrected Proton Density-Weighted In-Phase Stack-of-Stars (PDIP SOS) FLASH MR Imaging of Kidney Stone Disease
Robert R Edelman1,2, Emily A Aherne1, Sangtae Park3, Jianing Pang4, and Ioannis Koktzoglou1,5

1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, 3Surgery, NorthShore University HealthSystem, Evanston, IL, United States, 4Siemens Medical Solutions USA Inc, Chicago, IL, United States, 5Radiology, University of Chicago Pritzker School of Medicine, Chicago, IL, United States

Kidney stones affect 1 in 11 people in the United States and renal colic resulting from obstructing stones is a frequent cause of emergency department visits.  Non-contrast CT of the abdomen and pelvis is the primary imaging test but has the drawback of exposing the patient to potentially significant amounts of ionizing radiation.  A motion-corrected proton density-weighted in-phase stack-of-stars (PDIP SOS) FLASH pulse sequence was developed to provide a potential imaging alternative.  Using this approach, we have demonstrated for the first time the feasibility of using MRI to detect kidney stones with image quality that is competitive to CT. 

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Motion robust two-minute free-breathing hepatobiliary phase imaging of the liver using a golden-angle ordered conical acquisition with extended readout.
Ryan L Brunsing1, Joseph Y Cheng1, David Zeng2, Vipul R Sheth1, Signy Holmes1, and Shreyas S Vasanawala1

1Department of Radiology, Stanford University, Palo Alto, CA, United States, 2Electrical Engineering, Stanford Univresity, Palo Alto, CA, United States

Imaging of the liver can be compromised by motion artifacts which are especially problematic in patients with breathing difficulties. Non-Cartesian k-space sampling trajectories are motion robust and have shown promise in hepatobiliary-phase (HBP) imaging of the liver. Here we demonstrate that free-breathing HBP imaging can be obtained using a 3D cones k-space trajectory with golden angle ordering and extended readout (T1gER). The protocol shows similar performance to a conventional respiratory navigated sequence and can be acquired in less than half the time.

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Axillary MRI relaxometry as a tool for assessing risk of lymphedema development
Paula M.C. Donahue1, Rachelle M.C. Crescenzi2, and Manus Donahue2

1Physical Medicine and Rehabilitation, Vanderbilt University Medical Center, Nashville, TN, United States, 2Radiology, Vanderbilt University Medical Center, Nashville, TN, United States

We applied a novel application of T2 mapping in a longitudinal study to evaluate whether MRI relaxometry may hold more potential than current measures for portending breast-cancer-treatment-related-lymphedema (BCRL) progression. Baseline biophysical and T2 measurements were performed in patients following lymph node removal.  Patients were then monitored for BCRL progression (duration=two years). Baseline descriptive (age, BMI, number of nodes removed) and biophysical (bioimpedance, tissue dielectric, and arm volume) measures did not discriminate between patients who did vs. did not progress, yet baseline T2 was regionally elevated in those who progressed. MRI relaxometry may serve as a tool to identify BCRL risk.

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Texture Analysis Comparison between MR and PET for Prostate Cancer MRI Guided Biopsy
Raisa Binte Rasul1, Joshua Cornman-Homonoff2, Sadek Nehmeh2, and Daniel Margolis2

1Biomedical Engineering, Cornell University, Ithaca, NY, United States, 2Radiology, Weill Cornell Medicine, New York City, NY, United States

PET scans can detect prostate lesions, locations in the prostate where biopsy could reveal about treatment strategy. PET has low resolution compared to MRI and doesn't show surrounding anatomy necessary for accessing the prostate. Texture feature maps in MRI might include information about lesion location. MRI prostate texture features maps were compared with superimposed PET scans. Preliminary data suggest correlation between PET intensity and PI-RADS score, and weak correlation between less texture and lesion location. Though low texture values might correlate with higher tumor recurrence risk and lead to improved MRI-guided biopsy, finding exact lesion location in MRI remains challenging.

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Cylinder 3D radial acquisition for reduced imaging artifacts and better resolution at 1.5 T
Yajing Zhang1, Jiazheng Wang2, and Chenguang Zhao1

1Philips Healthcare, Suzhou, China, 2Philips Healthcare Greater China, Beijing, China

We have developed a novel 3D radial sequence for motion insensitive MRI, which replaces the frequency encodings in the radial plane in prior-art stack-of-star sequences with stepwise phase encodings to reduce the streaking artifacts that can arise from chemical shifts and system imperfections. The sequence achieved better image homogeneity with less imaging artifacts when compared to the prior-art sequence at 1 mm isotropic resolution with golden angle acquisition, both in phantom and in human brain and abdomen imaging.

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How long a 4D-MRI do we need for abdominal radiotherapy treatment planning? A time dependence analysis of abdominal motion probability distribution function using ultra-fast volumetric dynamic MRI
Yihang Zhou1, Jing Yuan1, Oi Lei Wong1, Kin Yin Cheung1, and Siu Ki Yu1

1Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Hong Kong, China

Radiotherapy (RT) treatment planning (TP) based on probability distribution function (PDF) is an evolving approach for tumor motion management. In PDF-TP, the dose distribution is weighted by the probability of the tumor being in that location during the treatment, thus the determination of reliable tumor motion PDF from time resolved dynamic imaging, named 4D-imaging, is essential. Ideally, a 4D-MRI should be as long as or even longer than the real abdominal RT treatment to represent the real motion pattern and account for any motion irregularity in the treatment, but it is actually impractical. Thus, another unanswered question is how long a 4D-MRI scan is really needed in order to obtain a tumor motion PDF as reliable as possible but keep acquisition as short as possible. In this study, we aim to determine the optimal 4D-MRI duration for PDF-TP by analyzing the time dependency of different abdominal organs’ PDF using an ultrafast volumetric 4D-MRI.

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Dynamic contrast-enhanced MRI of the liver: comparison between radial VIBE with k-space weighted image contrast reconstruction (r-VIBE-KWIC) and Golden-angle RAdial Sparse Parallel (GRASP)
Yasunari Fujinaga1, Akira Yamada1, Ayumi Ohya1, Hirokazu Tokoro1, Takeshi Suzuki1, Hayato Hayashihara2, Aya Shiobara2, Yasuo Adachi2, Yoshihiro Kitou2, Marcel Dominik Nickel3, Terumasa Takemaru4, Hirokazu Kawaguchi5, and Katsuya Maruyama5

1Department of Radiology, Shinshu University, School of Medicine, Matsumoto, Japan, 2Radiology Division, Shinshu University Hospital, Matsumoto, Japan, 3MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany, 4Department of Application, Siemens Healthcare K. K., Tokyo, Japan, 5Diagnostic Imaging Business Area, DI Research & Collaboration Dpt., Siemens Healthcare K. K., Tokyo, Japan

We aimed to evaluate the differences of the DCE-MR images between radial VIBE with k-space weighted image contrast reconstruction (r-VIBE-KWIC) and Golden-angle RAdial Sparse Parallel (GRASP). DCE-MRI using r-VIBE-KWIC and GRASP was performed in 36 and 35 patients, respectively. The most optimal arterial phase image was selected from eight sub-frame images at arterial phase, and factors of image quality in the both two groups were assessed using five-point scales. In GRASP, the median scores for all factors except for one were significantly higher than those in r-VIBE-KWIC. In conclusion, GRASP provided the better DCE-MR images than r-VIBE-KWIC.

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Cerebral Venous Oxygenation in the Human Fetuses With Enlarged Ventricles Using QSM
Brijesh Kumar Yadav1,2, Taotao Sun3, Feifei Qu2, E Mark Haacke1,2, Ling Jiang3, and Zhaoxia Qian3

1Department of Biomedical Engineering, Wayne State University, Detroit, MI, United States, 2Department of Radiology, Wayne State University, Detroit, MI, United States, 3Department of Radiology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China

Fetal growth and development is a delicate process which relies on the optimal oxygen supply to the fetus. Obstruction to this supply might cause delayed myelination or white matter damage which in turn, may lead to enlargement of cerebral ventricles. therefore, cerebral venous oxygenation (SvO2) was estimated in second and third trimester fetuses with enlarge ventricles using quantitative susceptibility mapping. Average SvO2 was found to be 68.2%±5.1% and a decreasing trend in SvO2 across gestation was observed in the fetal cohort with enlarge ventricles.

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Amide proton transfer imaging for rectal cancer: correlation with IVIM, DCE MRI and 18F-FDG-PET/CT
Yuichi Kumagae1, Yoshihiko Fukukura1, Hiroto Hakamada1, Hiroaki Nagano1, Jochen Keupp2, Yuta Akamine3, and Takashi Yoshiura1

1Kagoshima University, Kagoshima, Japan, 2Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany, 3Philips Electronics, Japan, Tokyo, Japan

This study focused on the correlation between amide proton transfer (APT) imaging and IVIM, DCE MRI or 18F-FDG PET/CT in rectal cancer. Our results showed a significant positive correlation between APT signal intensity (APT SI) and SUVmax (p = 0.005, ρ = 0.547). No significant correlation was shown between APT SI and IVIM (ADC, f, D* or D) or DCE MRI parameters (Ktrans, Kep, Ve or Vp). These results suggested that APT imaging reflects some metabolism of the rectal cancer and may be useful for response prediction after chemotherapy.

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Pseudo continuous arterial spin labeling perfusion MRI of advanced rectal cancer: utility in predicting response to neoadjuvant chemotherapy
Yuichi Kumagae1, Yoshihiko Fukukura1, Hiroto Hakamada1, Hiroaki Nagano1, Masanori Nakajo1, Tomoyuki Okuaki2, and Takashi Yoshiura1

1Kagoshima University, Kagoshima, Japan, 2Philips Electronics, Japan, Tokyo, Japan

This study focused on the feasibility of pseudo continuous arterial spin labeling (pCASL) perfusion MRI as a tool for predicting the response of advanced rectal cancer treated with neoadjuvant chemotherapy. Correlation between reduction rate of rectal cancer after chemotherapy and blood flow (BF) derived from pCASL or DCE MRI parameters within tumors was evaluated. Our results showed significant positive correlations between tumor reduction rate and BF (p = 0.001, ρ = 0.644) or Ktrans (p = 0.003, ρ= 0.579). These results suggested pCASL may have the potential to predict the treatment response of neoadjuvant chemothoerpy for advanced rectal cancer.

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Radiomics Based on MR Imaging of Rectal Cancer: Assess Treatment Response to Neoadjuvant Chemoradiotherapy
Fu Shen1, Jie Li2, and Jianping Lu1

1Radiology Department, Changhai Hospital, Shanghai, China, 2Huiying Medical Technology Co., Ltd., Beijing, China

The goal of this study was to investigate the value of high resolution T2-weighted–based radiomics in prediction of treatment response to neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC). The result demonstrated that the MRI based radiomics machine learning model could assess tumoral treatment response to nCRT in patients with LARC.

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MRI-based R2* Mapping in Patients with Suspected or Known Iron Overload
An Lesage1, Philippe Paquin1, Jack W Luo2, Milena Cerny1,3, Anne Shu-Lei Chin1, Damien Olivié1, Guillaume Gilbert1,4, Denis Soulières5, and An Tang1,3

1Department of Radiology, Centre hospitalier de l'Université de Montréal, Montréal, QC, Canada, 2McGill University, Montréal, SK, Canada, 3Centre de recherche du Centre hospitalier de l'Université de Montréal, Montréal, QC, Canada, 4MR Clinical Science, Philips Healthcare Canada, Markham, ON, Canada, 5Department of Hematology-oncology, Centre hospitalier de l'Université de Montréal, Montréal, QC, Canada

The purpose of this study is to analyze the cross-sectional relationships of MRI-based R2* relaxometry values in organs across patients with various types of iron overload. Further analyses were conducted to analyze R2* values in organs according to the treatment regimen of patients (transfusion, phlebotomy, and chelation therapy). This retrospective, cross-sectional study includes 82 adult patients with known or suspected iron overload due to primary and secondary hemochromatosis. Results revealed differences between degree of iron overload in organs according to the underlying pathology and treatment regimens.

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MRI Quantitative Parameters of Small-Bowel Perfusion for Early Diagnosing and Assessing Activity of Crohn’s Disease: A Preliminary Study
Xianying Zheng1

1Radiology, First Affiliate Hospital of Fujian Medical University, Fuzhou, Fujian, China

The purpose of this present study is to explore the potential of MR small-bowel perfusion, and to achieve more insights in MRE of CD patients. To this end, the changes of microcirculation of CD are investigated by comparing the quantitative parameters of MR perfusion of inflammatory segments with normal ones and the correlation of the former with CDAI and intestinal wall thickness.

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Comparison of MAGiC and MR Fingerprinting for Quantitative Relaxation of T1 and T2 Maps in Female Pelvis
Gigin Lin1, Guido Buonincontri2,3, Jianxun Qu4, Ching-Yi Hsieh1, and Chien-Yuan Eddy Lin5

1Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan, 2IMAGO7 Foundation, Pisa, Italy, 3National Institute for Nuclear Physics, Pisa, Italy, 4GE Healthcare MR Research China, Beijing, China, 5GE Healthcare, Taipei, Taiwan

T1 and T2 mapping of tissues provides valuable information for characterization of tissue pathologies but is limited by long scan time and consequently hampered the clinical practice. Magnetic resonance image compilation (MAGiC) and Magnetic resonance fingerprinting (MRF) are novel imaging techniques to simultaneously provide quantitative maps of tissue relaxation times in a single acquisition. This study aimed to compare the quantitative values of T1 and T2 in the female pelvic region using the MAGiC and MRF.

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Feasibility of abdominal quantitative imaging at 7T: pilot study.
Radim Kořínek1, Korbinian Eckstein2, Zenon Starčuk jr.1, Siegfried Trattnig2, and Martin Krššák2,3

1Institute of Scientific Instruments of the CAS, Brno, Czech Republic, 2Department of Biomedical Imaging and Image-guided Therapy, High Field MR Centre, Medical University of Vienna, Vienna, Austria, 3Department of Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Vienna, Austria

This work demonstrates abdominal proton density fat fraction (PDFF)-MRI quantification at 7T magnetic field. Four healthy volunteers with low liver fat infiltration assumption were measured with a 3D-MGE-T1w sequence using 32-channel Rx/Tx array coil at 7T whole body MR scanner. 7T data were reconstructed by complex-based multiecho water-fat separation methods. The same volunteers were measured at a 3T MR system with multiecho Dixon MRI and multiecho single voxel MRS as reference measurements. The results show the feasibility of quantitative liver imaging at 7T.

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RM-GROWL-GRASP: Image Registration Involved Two-step Motion Compensation System for Real-time Non-Cartesian Liver DCE-MRI
Zhifeng Chen1,2, Peiwei Yi1,2, Zhongbiao Xu1,2, Jucheng Zhang3, Yingjie Mei1,2, Xia Kong4, Zhenguo Yuan5, Yaohui Wang6, Ling Xia7, Yanqiu Feng1,2, and Feng Liu8

1School of Biomedical Engineering, Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China, 2Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China, 3Department of Radiology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China, 4School of Computer and Information Science, Hubei Engineering University, Wuhan, China, 5Shandong Medical Imaging Research Institute, Shandong University, Jinan, China, 6Division of Superconducting Magnet Science and Technology, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China, 7Department of Biomedical Engineering, Zhejiang University, Hangzhou, China, 8School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD, Australia

Motion is an inescapable problem in abdominal MRI. Involuntary organ movements caused mainly by respiratory often results in motion artifacts and image details blurring in liver MRI. For dynamic imaging, motion also harms temporal information. Recently, high spatiotemporal resolution free-breathing liver DCE-MRI have attracted much attentions of radiologists and scholars. We propose to combine mutual-information-based image registration with motion-sorted GROWL-GRASP approach for golden-angle radial liver DCE-MRI, which enable free-breathing imaging. The results demonstrate that better image quality including SNR benefit, lower motion artifacts and more diagnostic information can be generated compared to current motion compensation methods.

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Multi-frequency spin echo- magnetic resonance elastography (SE-MRE) to non-invasively assess kidney allograft injury - preliminary findings
Eyesha Hashim1, Prateek Kalra2, Arunark Kolipaka2, Darren Yuen3,4,5, and Anish Kirpalani1,6,7

1Medical Imaging, St. Michael's Hospital, Toronto, ON, Canada, 2The Ohio State University, Columbus, OH, United States, 3Division of Nephrology, Department of Medicine, St. Michael's Hospital, Toronto, ON, Canada, 4|Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada, 5Division of Nephrology, Department of Medicine, The University of Toronto, Toronto, ON, Canada, 6Medical Imaging, University of Toronto, Toronto, ON, Canada, 7Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada

Chronic allograft injury (CAI) is typically indicated too late with blood work and its cause is determined invasively (e.g. via biopsy). It is thus important to develop non-invasively tools to identify CAI early. We used multi-frequency spin-echo magnetic resonance elastography (SE-MRE) to assess shear modulus as an estimate of CAI in a group of kidney allograft patients with stable but sub-normal graft function. We observed a negative trend approaching significance, between the graft function as determined by estimated glomerular filtration rate and the shear modulus at 90Hz suggesting that SE-MRE can potentially be used for non-invasive assessment of renal injury.

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Towards systematic evaluation of velocity-selective ASL in the measurement of placental perfusion
Anita A. Harteveld1, Jana Hutter2, Suzanne L. Franklin1,3, Laurence Jackson2, Mary Rutherford2, Joseph V. Hajnal2, Matthias J. P. van Osch3, Clemens Bos1, and Enrico De Vita2

1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Center for Biomedical Engineering, King’s College London, London, United Kingdom, 3C.J. Gorter Center for high field MRI, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

The placenta’s role as a nutrient and oxygen source for the fetus highly depends on blood supply and thus perfusion may be a sensitive marker of placenta function. Velocity-selective arterial spin labeling (VSASL) placental perfusion measurements have previously been demonstrated using standard parameter settings from the brain. In this study, the influence of different VSASL parameter settings was assessed to optimize measurement of placental perfusion. The results of this study will improve our understanding and interpretation of the measured perfusion signals in the placenta. 

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Delineating Benign from Malignant Breast Lesions Using Restriction Spectrum Imaging
Alexandra Besser1, Ana Rodriguez-Soto1, Hauke Bartsch1, Helen Park2, Andrew Park2, Haydee Ojeda-Fournier1, Anders Dale1, and Rebecca Rakow-Penner1

1Radiology, University of California San Diego, La Jolla, CA, United States, 2School of Medicine, University of California San Diego, La Jolla, CA, United States

Non-contrast diffusion MRI holds great potential to screen women for breast cancer. Restriction spectrum imaging (RSI) is an advanced diffusion-weighted imaging (DWI) technique that reflects the high nuclear to cytoplasm ratio observed in cancer cells. This abstract explores RSI as a technique to non-invasively identify malignant from benign masses on non-contrast MRI by measuring RSI cellularity index (RSI-CI). Biopsy-proven malignant masses demonstrate high cellularity index compared to benign lesions. In this pilot study, RSI differentiates malignant from benign masses without contrast imaging, and could prove useful as a screening tool.

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Reducing T2-shinethrough effects in prostate diffusion-weighted imaging with Stimulated Echo imaging
Yuxin Zhang1,2, Shane A Wells2, Benjamin L Triche2, Frederick Kelcz2, and Diego Hernando1,2

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

The bright appearance of long-T2 tissues in DWI, termed “T2-shinethrough”, reduces the contrast between healthy tissue and cancer and is prominent in spin-echo based DWI acquisitions. In prostate DWI, the need to avoid T2-shinethrough has led to the acquisition of very high b-values in clinical practice, which may result in low SNR and other image artifacts. In this work, we have assessed the ability of stimulated-echo DWI to provide high contrast between PCa and healthy peripheral zone, without the need for high b-values. Preliminary results in 19 patients show reduced T2-shinethrough effects in stimulated-echo DWI compared with spin-echo DWI.

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Denoising and Multi-Compartment Visualization of Multi-b-Valued Breast Diffusion MRI
Ek Tsoon Tan1, Lisa J Wilmes2, Nola Hylton2, Thomas L Chenevert3, and David C Newitt2

1GE Global Research, Niskayuna, NY, United States, 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, 3Department of Radiology, University of Michigan, Ann Arbor, MI, United States

Multi-b-valued diffusion-weighted imaging (DWI) of the breast is highly susceptible to image and fitting noise. A multi-compartment approach was developed to denoise multi-b-value breast DWI without spatial smoothing. In human subject exams (N=12), the denoising approach resulted in a significant reduction in variability of all perfusion and diffusion maps in breast tumor and normal fibroglandular tissue with minimal bias to the mean values, and increased statistical separation of diffusivity metrics between tumor and normal tissue. The denoising algorithm provides compartment fractions for tumor, tissue, and vascularity, which may improve visualization of tissue compartments in DWI.

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Slip-interface imaging preoperatively predicts hepatocellular carcinoma microvascular invasion
Bing Hu1, Ziying Yin2, Kevin J. Glaser2, Ying Deng1, Sichi Kuang1, Li Quan1, Jun Chen2, Arvin Arani2, Meng Yin2, Sudhakar K. Venkatesh2, Richard L. Ehman2, and Jin Wang1

1Department of Radiology, the Third Affiliated Hospital, Sun Yat-sen University (SYSU), Guangzhou, China, 2Department of Radiology, Mayo Clinic, Rochester, MN, United States

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults. One of the most strongly correlated factors predicting outcome is the presence or absence of vascular invasion. Since microvascular invasion cannot be found with conventional CT or MRI examination, we investigated whether slip-interface imaging (SII) could identify HCC microvascular invasion.  The results showed that in 32 of 33 patients with HCC, SII-assessed microvascular invasion agreed with pathology, indicating that this technique may become useful for detecting HCC microvascular invasion and guiding treatment planning.


Pancreas/GI

Exhibition Hall
Monday 13:45 - 14:45
 Body: Breast, Chest, Abdomen, Pelvis

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Detection of Pancreatic Ductal Adenocarcinoma and Liver Metastases: Comparison of Contrast-enhanced MR Imaging with Ga-EOB-DTPA and Extracellular Contrast Materials
Yoshifumi Noda1, Satoshi Goshima1, Yukiko Takai1, Nobuyuki Kawai1, Hiroshi Kawada1, Yukichi Tanahashi1, Kimihiro Kajta1, and Masayuki Matsuo1

1Radiology, Gifu University, Gifu, Japan

Ga-EOB-DTPA-enhanced MR imaging is well established imaging modality for the detection of liver metastases. On the other hand, it is expected that the arterial enhancement of solid organs is weaker comparing with extracellular contrast materials (ECCMs) because of its lower dosage. Our results demonstrated that the signal intensity ratio of the pancreas, tumor-to-pancreas contrast-to-noise ratio, and diagnostic performance for detecting pancreatic ductal adenocarcinoma (PDAC) were comparable, but the sensitivity for detecting liver metastases was better in Ga-EOB-DTPA compared with ECCMs, which suggests the usefulness of Ga-EOB-DTPA for evaluating patients with PDAC.

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Pancreatic and hepatic iron predict prediabetes in chronically transfused patients with sickle cell disease.
Andrew L Cheng1, Thomas D Coates1, and John C Wood1

1Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, United States

Pancreatic iron is common in transfused sickle cell disease(SCD) patients but the functional significance is unknown.  We compared pancreatic function with hepatic and pancreatic iron burden by MRI in 28 SCD patients.  Six patients had impaired fasting glucose(IFG) values and one had impaired glucose tolerance. Insulin resistance was positively associated with body mass index and negatively associated with liver iron concentration (r2 = 0.50, p<0.004). Liver iron and serum ferritin predicted IFG with an AUROC of 0.82 and 0.86 respectively. Beta cell function was inversely proportional to pancreatic R2* (r2 = 0.17, p=0.01). Thus, prediabetic changes were common and related to liver and pancreatic iron.

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MR measurement of T1 relaxation time and fat signal fraction of the pancreas: Association with HbA1c values
Mayumi Higashi1, Masahiro Tanabe1, and Katsuyoshi Ito1

1Radiology, Yamaguchi University, Ube, Yamaguchi, Japan

The purpose of this study was to evaluate the association of the T1 relaxation time and FSF of the pancreatic parenchyma measured by MRI with HbA1c value. The T1 relaxation time on the T1 map images with fat suppression and FSF on fat fraction images of the pancreatic parenchyma were measured. We assessed the correlation between the MRI measurements and HbA1c values. The FSF (%) of the pancreatic parenchyma was significantly correlated with HbA1c values while the T1 relaxation times were not. The FSF (%) of the pancreas may be a potential imaging biomarker for impaired glucose tolerance.

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Pancreatic adenocarcinoma: Variability in measurements of tumor size among CT, MRI and pathologic specimen
Chao Ma1, Panpan Yang1, Yun Bian1, Jing Li1, Li Wang1, and Jianping Lu1

1Radiology, Changhai Hospital of Shanghai, Shanghai, China

The aim of the study is to investigate the measurements obtained from the preoperative contrast-enhanced both computed tomography (CT) and magnetic resonance imaging (MRI) with pathologic specimen in measuring the size of pancreatic cancer. It was found in this study, both contrast-enhanced CT and MRI underestimate mean tumor size by 3.3 mm and 4.7 mm respectively, when compared with the size of pathologic specimen.

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Computer-aided pancreas segmentation based on 3D GRE Dixon MRI
Chao Ma1, Xiaoliang Gong2, Panpan Yang1, Yufei Chen2, Chaolin Du2, Caixia Fu3, Xu Yan4, and Jianping Lu1

1Radiology, Changhai Hospital of Shanghai, Shanghai, China, 2Country Key Laboratory of Embedded System and Service Computing (Ministry of Education), Tongji University, Shanghai, China, 3Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 4Siemens Healthcare, Shanghai, China

Pancreas segmentation is of great significance for pancreatic cancer radiotherapy positioning, pancreatic structure and function evaluation, etc. In the study, we purposed a simple computer-aided pancreas segmentation method based on 3D GRE Dixon images by using a free open source software system. 

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MRI Relaxometry: Comparing R2* Values in Liver and Pancreas with respect to Disease Characteristics
Arthur Peter Wunderlich1,2, Stephan Kannengießer3, Lena Kneller1, Berthold Kiefer3, Holger Cario4, Meinrad Beer1, and Stefan Andreas Schmidt1

1Dept. for Diagnostic and Interventional Radiology, Ulm University, Medical Center, Ulm, Germany, 2Section for Experimental Radiology, Ulm University, Medical Center, Ulm, Germany, 3Siemens Healthcare, Erlangen, Germany, 4Clinic for Pediatric and Adolescent Medicine, Ulm University, Medical Center, Ulm, Germany

To study pancreatic iron accumulation in liver overloaded patients with respect to disease characteristics, 116 patients were investigated at 1.5 T MRI with a prototype breathhold 3D GRE protocol with in-line R2*calculation. Mean R2* values were determined in liver and pancreas by manually drawn ROIs. Pancreatic R2* values were correlated with liver R2* in patient subgroups according to transfusion frequency. Pancreatic R2* correlated significantly to liver R2* for sporadic or frequently transfused patients, was normal in patients requiring no transfusion, and elevated in most regular transfused patients. After bone marrow transplant, most patients showed only slightly raised pancreatic R2*.

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Quantitative dynamic contrast-enhanced MR imaging for prediction of the response to gemcitabine in pancreatic ductal adenocarcinoma: a preliminary study
TANG WEI1, Cai-xia Fu2, Wei LIU1, and Wei-jun PENG1

1Radiology, Fudan University Shanghai Cancer Center, Shang Hai, China, 2Siemens Healthcare, MR Collaborations NE Asia, Shanghai, China, Shang Hai, China

This study aimed to explore the feasibility of dynamic contrasted enhancement MRI (DCE-MRI) for predicting the response to gemcitabine in pancreatic ductal adenocarcinoma, as well as the influence of different region of interests (ROIs) on quantitative parameters. We compared the differences of DCE-MRI parameters between responders and non-responders. Kep based on periphery ROI was the best predictive marker, showed the highest areas under ROC curve (AUC) of 0.806. Quantitative DCE-MRI may be a feasible method, and the parameters are useful for the prediction of response to gemcitabine in patients with PAC. The positions of ROI influenced the DCE-MRI parameters.

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Quantification of Pancreatic Fat Content in Patients with Essential Hypertension using IDEAL-IQ sequence
Zhang Qinhe1, Liu Ailian1, and Xie Lizhi2

1The first affiliated hospital of Dalian Medical University, Dalian, China, 2GE Healthcare, MR Research China, Beijing, Beijing, China

The study aims to assess the pancreatic fatty quantitation in patients with hypertension using IDEAL-IQ. IDEAL-IQ is a new way to evaluate the pancreatic fat quantification in patients with hypertension. The fat fraction of the pancreas in patients with hypertension is significantly higher than that in normal subjects,and the longer the length of the duration of the disease is, the higher the fat fraction of the pancreas is.

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Differentiation of Pancreatic Head Ductal Adenocarcinoma from Inflammatory Pancreatic Pseudomass by MR Cholangio-pancreatography: Utility of the Duct-interrupted, Corona and Attraction Signs
Alejandro Garces-Descovich1, Kevin Beker1, Leo Tsai1, Karen Lee1, Tarek Hegazi1, Alexander Brook2, Adrian Jaramillo-Cardoso1, and Koenraad Mortele1

1Division of Body MRI, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

To properly treat and determine a truthful prognosis, accurate pancreatic head mass differentiation is fundamental. Pancreatic ductal adenocarcinoma (PDAC) of the head and inflammatory pancreatic pseudomass (IPP) simulate significantly to each other in clinical imaging. We proposed the use of three radiological signs ("duct-interrupted”, “corona”, and “attrition” signs) on magnetic resonance cholangio-pancreatography (MRCP). The proposed signs were assessed by three blinded radiologist, demonstrating high specificity for diagnosing PDAC by the “duct-interrupted” and “corona” signs, while good specificity of the “attraction” sign to identify IPP. 

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Radiomics of Magnetic Resonance Imaging of Pancreas-Towards Improved Diagnosis and Management of Pancreatic Cancer
Touseef Ahmad Qureshi1, Lixia Wang1, Srinivas Gaddam2, Nan Wang1, Zixin Deng1, Simon Ahmad Lo2, Andrew Hendifar3, Zhaoyang Fan1, Stephen Pandol2, and Debiao Li1

1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Department of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 3Department of Gastrointestinal Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, United States

The MRI-based Radiomics of pancreas can identify several imaging-characteristics (e.g. texture, shape, signal intensity, etc.) that are distinct in healthy and cancerous pancreas. We performed MRI-based radiomics of pancreas to demonstrate that radiomics play an important rule to differentiate healthy and cancerous pancreas and can assist diagnosis and management of PC. Multiple statistical tests demonstrated that 18% of the total 250 radiomic features were significantly different between healthy and cancerous pancreas. These features have high diagnostic accuracy to detect PC. We conclude that MRI-based radiomics of pancreas can potentially have a future role in early detection, prognosis, and prediction of treatment outcome of PC.

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Usefulness of amide proton transfer imaging in the evaluation of autoimmune pancreatitis activity
Yoshihiko Fukukura1, Yuichi Kumagae1, Hiroto Hakamada1, Hiroaki Nagano1, Takashi Iwanaga2, Jochen Keupp3, Yuta Akamine4, and Takashi Yoshiura1

1Kagoshima University Graduate School of Medical and Dental Sciences, kagoshima, Japan, 2Department of Radiological Technology, Kagoshima University Hospital, Kagoshima, Japan, 3Philips GmbH Innovative Technologies Research Laboratories, Hamburg, Germany, 4Philips Electronics Japan, Tokyo, Japan

This study focused on the potential of amide proton transfer (APT) MR imaging at 3.0T as an objective imaging biomarker in patients with autoimmune pancreatitis (AIP). Correlation of serum immunoglobulin G4 (IgG4) levels with APT SI, the apparent diffusion coefficient (ADC) values or the maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) was evaluated in eleven patients with AIP. Our results showed a significant positive correlation between serum IgG4 levels and APT signal intensity (SI). Therefore, APT imaging might be useful for monitoring AIP activity.

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Extracellular volume fraction on Gd-EOB-DTPA-enhanced MRI for predicting overall survival in patients with metastatic pancreatic adenocarcinoma
Yoshihiko Fukukura1, Yuichi Kumagae1, Hiroto Hakamada1, Hiroaki Nagano1, Kiyohisa Kamimura1, Tomohide Yoneyama1, Masanoari Nakajo1, and Takashi Yoshiura1

1Kagoshima University Graduate School of Medical and Dental Sciences, kagoshima, Japan

This study focused on the potential of extracellular volume (ECV) fraction measured by Gd-EOB-DTPA-enhanced MRI as a prognostic factor in patients with metastatic pancreatic adenocarcinomas. The effect on survival of variables including age, sex, tumor location, tumor size, TNM factors, serum carbohydrate antigen (CA) 19-9 and carcinoembryonic antigen (CEA) levels and tumor ECV fraction was assessed in patients with metastatic adenocarcinoma. Our results showed that pancreatic adenocarcinoma with higher ECV fraction had better prognosis. Therefore, ECV fraction measured by MRI before and 5 min after Gd-EOB-DTPA administration may be a useful semiquantitative marker of patient prognosis in metastatic pancreatic adenocarcinoma.

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Robust Breath-hold Three-Dimensional (3D) MRCP using Contrast-Enhanced Timing Robust Acquisition Order with a Preparation of the Longitudinal Signal Component(CENTRA-Plus) Technique at 3T
Yoshihiro Ikeda1, Yasuhiro Goto1, Masami Yoneyama2, Isao Shiina1, Yutaka Hamatani1, Kazuo Kodaira1, Yu Nishina3, Satoru Morita3, and Shuji Sakai3

1Department of Radiological Services, Tokyo Women's Medical University Hospital, Tokyo, Japan, 2Philips Electronics Japan, Tokyo, Japan, 3Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women's Medical University Hospital, Tokyo, Japan

The present study investigates the clinical utility of motion-insensitive breath-hold 3D MRCP using contrast-enhanced timing robust acquisition order with a preparation of the longitudinal signal component(CENTRA-Plus). 3D MRCP image derived from breath0holding with CENTRA-Plus showed good correlations to those from conventional respiratory triggering technique. Breath hold 3D MRCP with CENTRA-Plus can reduce scan time (around 80% of the scan time) without any penalty for the image quality; therefore, it might contribute to great advantages in routine clinical work.  

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Quantitative dynamic contrast-enhanced magnetic resonance imaging as a potential tool for preoperative predicting the response to neoadjuvant chemotherapy in locally advanced gastric adenocarcinoma
Yongjian Zhu1, Ying Li1, Jun Jiang1, Wen Zhang2, Liming Jiang1, and Lizhi Xie3

1Department of Imaging Diagnosis, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, 2Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, 3GE healthcare, China, Beijing, China

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been applied in diagnosis of different cancers, however its potential in gastric cancer has not been fully explored. In this study, we research into the value of DCE-MRI parameters in evaluating the response to chemotherapy in gastric cancer. It was found that the Ktrans and Ve values showed good predictive performance through distinguishing responders from non-responders, which could provide effective technical assistance for the choice of clinical treatment.

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Pulsatility and Resistivity Indices in Mesenteric Vasculature in Patients Suspected of Chronic Mesenteric Ischemia using 4D Flow MRI
Grant S Roberts1, Christopher J Francois2, Alejandro Roldan-Alzate2, and Oliver Wieben1,2

1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, 2Radiology, University of Wisconsin - Madison, Madison, WI, United States

Chronic mesenteric ischemia (CMI) causes blood flow reduction in the intestines, often due to atherosclerosis. This study uses 4D flow MRI to quantify and compare pulsatility (PI) and resistivity indices (RI) in mesenteric vasculature in patients with a suspicion of CMI (N=19) and healthy individuals (N=20). PI and RI were measured in 9 mesenteric vessels before and after meal ingestion. In patients with CMI, aortic PI were significantly decreased both before and after a meal compared to controls, while postprandial SV and SMV PI values were significantly increased. RI values were not significantly different between groups.

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Assessment and Classification of Motility of Terminal Ileum in Crohn’s Disease on Cine Magnetic Resonance Enterography
Basak Bayrambas1, Esin Ozturk-Isik1, and Oktay Algin2

1Biomedical Engineering Institute, Bogazici University, Istanbul, Turkey, 2Department of Radiology, Yildirim Beyazit University Medical School, Ankara, Turkey

Crohn’s disease is an inflammatory bowel disease mostly affecting motility in terminal ileum of small bowel. In this study, cine magnetic resonance enterography scans were used to assess the terminal ileum motility. Motility was quantified using optical flow based and gradient based analysis. ROC statistical analysis showed that immotility and motility were separable with 87% accuracy when analyzed with optical flow based algorithm and 89% accuracy with gradient based algorithm. The best classification accuracy of 90.5% was obtained when both optical flow and gradient based analysis results were used as features to train a kNN algorithm with 15-fold cross validation.

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A new MR-based Perianal Crohn’s disease activity score: Multicentre study
Ali Alyami1,2,3, Caroline Hoad1,3, Konstantinos Argyriou4, White Jonathan4, Uday Bannur5, Khalid Latief5, Christopher Clarke5, Phillip Lung6, Penny Gowland3, and Gordon Moran1,4

1Nottingham Digestive Diseases Centre, University of Nottingham, Nottingham, United Kingdom, 2Faculty of Applied Medical Sciences, Diagnostic Radiology, Jazan University, Jazan, Saudi Arabia, 3Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 4NIHR Nottingham Biomedical Research Centre at Nottingham University Hospitals NHS Trust and University of Nottingham, University of Nottingham, Nottingham, United Kingdom, 5Radiology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom, 6Radiology, St Mark's Hospital and London North West Healthcare NHS Trust, London, United Kingdom

Perianal Crohn’s disease (pCD) is a potential complication in CD. Absence of reliable disease measures makes disease monitoring unreliable. MRI is an effective imaging method for the evaluation of patients with pCD. Quantitative MRI sequences, such as diffusion-weighted image (DWI), and magnetization transfer (MT) offer opportunities to improve diagnostic capability. The aim of this study was to measure disease activity within a pCD patient cohort using quantitative MRI sequences (DWI and MT), at different field strengths, before and after biological therapy. The study is ongoing with patients presenting with a range of clinical and inflammatory markers of disease activity.

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Quantification of MT in the bowel wall from the z-spectrum
Andrew Carradus1, Olivier Mougin1, Hannah G Williams1, Caroline Hoad1, and Penny Gowland1

1University of Nottingham, Nottingham, United Kingdom

We have developed a protocol able to measure and quantify MT in the bowel wall through acquisition of the z-spectrum at 3T, and have developed a protocol capable of eliminating respiratory artefacts which have the potential to invalidate MT abdominal imaging.

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Pre and Postprandial Hemodynamics of the Gastroduodenal Artery in Patients Suspected of Chronic Mesenteric Ischemia using 4D Flow MRI
Grant S Roberts1, Christopher J Francois2, Alejandro Roldan-Alzate2, and Oliver Wieben1,2

1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, 2Radiology, University of Wisconsin - Madison, Madison, WI, United States

Chronic mesenteric ischemia (CMI) causes reduced intestinal blood flow, often from mesenteric occlusions. However, collaterals exist and help compensate for reduced blood flow. This study utilizes 4D flow MRI to quantify hemodynamics in the gastroduodenal artery (GDA), a collateral between the celiac and superior mesenteric arteries, in controls (N=14) and patients suspected of CMI (N=14) before and after a meal. There was no significant difference in preprandial, postprandial, or percent flow change values between groups. However, pathology-dependent flow patterns were evident within the ischemia group. Follow-up studies with larger cohorts are warranted to further examine this finding.

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Radiomics features of gastrointestinal stromal tumors (GISTs) based on whole-tumor analysis: the robust imaging biomarkers to stratification and monitoring purpose
ziling zhou1, zhen li1, jingyu lu1, hao yu1, daoyu hu1, and yaqi shen1

1Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, wuhan, China

The diagnosis and treatment plans of GISTs are relied on pathological confirmation, yet the biopsy for unresectable GISTs cannot always provide comprehensive information, which will have an impact on the treatment plan and duration. Radiomics features based on whole tumor analysis have been confirmed as a robust imaging biomarkers with good repeatability in some solid tumors. The present study using the method described above to analyze a group of patients with pathological confirmed GISTs, to determine which radiomics features are useful for stratification and monitoring purpose.

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Comparison of abdominal lymph nodes between healthy volunteers and patients with inflammatory gastrointestinal diseases.
Hannah G Williams1, Caroline L Hoad1, Robert Scott2, Gordon Moran2, Guruprasad P Aithal2, Luca Marciani2, and Penny A Gowland1

1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 2Nottingham Digestive Diseases Biomedical Research Centre, University of Nottingham, Nottingham, United Kingdom

Inflammatory diseases of the gastrointestinal tract are likely to cause enlargement of the abdominal lymph nodes which could potentially act as a biomarker of local inflammation. Lymphatics have been identified using a range of MRI sequences but previous work has largely focused on changes in cancer rather than chronic inflammatory diseases. We present here the first comparison of quantitative non-invasive MRI measures of T2, Apparent Diffusion Coefficient (ADC) and size of lymph nodes in healthy volunteers and patients with a range of inflammatory gastrointestinal diseases. 

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Comparison between 3T MRI and CT for preoperative T staging of resectable esophageal cancer, with histopathological correlation
Jinrong Qu1 and Xu Yan2

1Radiology, Henan Cancer Hospital, Zhengzhou, China, 2MR Scientific Marketing, Siemens Healthcare, Shanghai, China

Seventy fourth patients with endoscopically proven EC and indeterminate T1/T2/T3/T4a stage by CT and EUS were enrolled prospectively. The diagnostic performances of MRI and CT were evaluated based on the sensibility, specificity and accuracy rate, the difference of accuracy rates between MRI and CT was analyzed by c2 test. This study showed MRI can obtain clear images of esophageal wall for preoperative T staging of EC with significantly higher accuracy rate than that of CT, and provide another high-accuracy non-invasive examination method for preoperative T staging of EC.

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Relationship Between Exocrine Pancreatic Function and Abdominal Symptoms: Evaluation Using Cine-Dynamic MRCP
Akira Yamamoto1, Katsuyoshi Ito2, Teruki Sone1, Kazuya Yasokawa1, Akihiko Kanki1, and Tsutomu Tamada1

1Radiology, Kawasaki Medical School, Kurashiki, Japan, 2Radiology, Yamaguchi University, Ube, Japan

The purpose of this study was to elucidate the relationship between exocrine pancreatic function and abdominal symptoms. Cine-dynamic MRCP was performed and an 18-item questionnaire on abdominal symptoms was administered to 42 patients. The relationship between exocrine pancreatic function, which was quantified as an exocrine pancreatic score, and the abdominal symptoms was assessed. Symptoms for 3 of the 18 abdominal symptom items were significantly associated with decreased exocrine pancreatic function, as measured by cine-dynamic MRCP If a patient complains of such symptoms, the possibility of decreased exocrine pancreatic function should be considered, and should be evaluated by cine-dynamic MRCP.


Liver Lesions: Diagnosis, Characterization & Monitoring

Exhibition Hall
Monday 13:45 - 14:45
 Body: Breast, Chest, Abdomen, Pelvis

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Hepatocellular carcinoma: whole-lesion radiomics nomogram on gadoxetic acid-enhanced MR imaging for postoperative early recurrence prediction
Zhen Zhang1, Jie Chen1, Likun Cao1, Song Bin1, and Zhen Zhang1

1Department of Radiology, West China Hospital,Sichuan University, Chengdu, China

The high recurrence rates after curative resection has become a major obstacle for the treatment of HCC. Radiomics has been proposed as a robust and effective imaging analysis method to quantify tumor phenotypic characteristics. In this prospective study, a radiomics model based on preoperative gadoxetic acid-enhanced magnetic resonance (MR) images for preoperative prediction of early recurrence in HCCs was generated, with good discrimination and calibration, and may act as an accurate tool to preoperatively identify high-risk patients and guide clinical decision-making of this population.

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T1 mapping on gadoxetic acid-enhanced MR imaging for preoperative prediction of microvascular invasion in hepatocellular carcinoma
Zhen Zhang1, Song Bin2, and Zhen Zhang1

1Department of Radiology, West China Hospital,Sichuan University, Chengdu, China, 2West China Hospital,Sichuan University, Chengdu, China

Microvascular invasion (MVI) is regarded as one of the independent risk factors for recurrence and poor prognosis of hepatocellular carcinoma (HCC). However, reliable diagnosis of MVI can only be obtained postoperatively. In this study, preoperative T1 mapping on gadoxetic acid-enhanced MR imaging were performed on 79 patients to demonstrate potential imaging biomarkers in prediction of MVI and early recurrence. As a result, pre-contrast T1 relaxation time, reduction rate of T1 relaxation time combined with the presence of peritumoral hypointensity on HBP were found to be potential predictive biomarkers in the preoperative prediction of MVI in HCCs.

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Differential Diagnosis of Intrahepatic Mass-forming Cholangiocarcinoma and Solitary Hypovascular Hepatic Metastasis Using Whole-Tumor Texture Features Based on Apparent Diffusion Coefficient and Fractional Anisotropy Signal Intensity Maps
Ying Zhao1 and Ailian Liu1

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

This work aimed for ADC and FA texture features based strategy to identify intrahepatic mass-forming cholangiocarcinoma (IMCC) and solitary hypovascular hepatic metastasis (SHHM) which may represent a diagnostic challenge due to many overlapping MRI features. The results showed that ADC and FA texture features can differentiate IMCC and SHHM. The Grey Level Non-uniformity (GLN) achieved the best result (AUC: 0.820; sensitivity: 79.2%; specificity: 86.2%) on ADC signal intensity map, forming a valuable strategy for clinical practice.

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MR-based Radiomics Signature to Discriminate Different Pathologic Grade of Hepatocellular Carcinoma
Ying Zhao1, Ailian Liu1, Jingjun Wu1, and Jingjing Cui2

1The First Affiliated Hospital of Dalian Medical University, Dalian, China, 2Huiying Medical Technology Co., Beijing, China

Recently, the term radiomics (the extraction of multiple quantitative features from images) has drawn attention. Several cancer-related radiomics studies suggested that some quantitative imaging descriptors (such as texture features derived from MRI) could provide more information for cancer diagnosis. In the current study, MR-based radiomics signature was demonstrated to be capable to assess different pathologic grade of hepatocellular carcinoma, which will provide more prognostic information and facilitate clinical management.

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Quantitative MR image analysis for predicting histopathological growth patterns of liver metastases from colorectal cancer: standard mono-compartmental vs bi-compartmental model
Pietro Andrea Bonaffini1, Peter Savadjiev1, Sahir Bhatnagar1,2, Ayat Salman3, Zu-Hua Gao4, Anthoula Lazaris3, Peter Metrakos5, Benoit Gallix1, and Caroline Reinhold1

1Diagnostic Radiology, McGill University Health Center, Montreal, QC, Canada, 2Epidemiology, Biostatistics and Occupational Health, McGill University Health Center, Montreal, CA, Canada, 3HBP and Transplant Clinical Research, McGill University Health Center, Montreal, QC, Canada, 4Pathology, McGill University Health Center, Montreal, QC, Canada, 5General Surgery, McGill University Health Center, Montreal, QC, Canada

Morphologic and quantitative imagine biomarkers able to reliably and noninvasively determine the different histopathological growth patterns (HGP) of colorectal cancer liver metastases (CRCLM) are currently missing. We aimed to evaluate if a bi-compartmental model (tumour border region, in addition to an inner core region) can outperform the traditional mono-compartmental model for HGP subtype prediction. Our results show an improvement in HGP subtype classification when using the bi-compartmental tumour model, likely because the information arising from the borders are separate from those pertaining to the inner core. As reported, the main differences for HGP tend to occur at the tumour-liver parenchyma interface.  This would allow accurate and potentially more effective patient treatment stratification, since the different HGP subtypes have reported variable response rates to anti VEGF-A therapy. 


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The prediction value of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced MRI in Microvascular Invasion of Hepatocellular Carcinoma
Peipei Chen1, Jian Lu1, Tao Zhang1, Xueqin Zhang1, and Xiaofen Miao1

1Department of Radiology, Third People's Hospital of Nantong,China, Nantong, China

Hepatocellular carcinoma (HCC) is a common malignant tumor in the liver. Microvascular invasion (MVI) is one of the important risk factors affecting the recurrence and prognosis of HCC. Some scholars have predicted MVI through various imaging methods such as CT, MRI and PET, but has not yet reached a unified forecasting standard. Gadoxetate disodium(Gd-EOB-DTPA)is a novel hepatobiliary contrast agent. Peritumoral hypointension in hepatobiliary phase is of great value in predicting MVI, but the related studies are few. In this study, we used multiple parameters to analyze the value of Gd-EOB-DTPA enhanced MRI in predicting MVI qualitatively and quantitatively. 

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Imaging features of hepatic hemangiomas with Pseudo washout sign on Gd-EOB-DTPA enhanced MRI
Peipei Chen1, Jian Lu1, and Tao Zhang1

1Department of Radiology,The Third Hospital Affiliated of Nantong University, Nantong, China

Gadoxetate disodium(Gd-EOB-DTPA)is a novel hepatobiliary contrast agent with characteristics of conventional contrast agents and can also be taken up by liver cells specifically, which is beneficial in characterization of focal liver lesions. In clinical practice, some small hemangiomas usually show low signal in transitional phase of Gd-EOB-DTPA enhanced MRI, defined as Pseudo washout sign(PWS), which can be easily misdiagnosed as hepatocellular carcinoma (HCC) if diagnostic physician do not have sufficient experience. Our study intended to improve the understanding of hepatic hemangiomas with atypical imaging features by summarizing the imaging features of hepatic hemangioma with PWS in Gd-EOB-DTPA-enhanced MRI.

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Prediction for early recurrence of intrahepatic mass-forming cholangiocarcinoma: quantitative MRI combined with prognostic immunohistochemical marker
Li Zhao1, Xinming Zhao1, Lizhi Xie2, and Sicong Wang3

1Diagnostic Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and PekingUnion Medical College, Beijing, China, 2MR Research, GE Healthcare, Beijing, China, 3GE Healthcare, Beijing, China

The aim of this study was to develop a nomogram based on pathological characteristics, immunohistochemical molecules, conventional radiological features and texture parameters for predicting the early recurrence (ER) of intrahepatic mass-forming cholangiocarcinoma (IMCC). It was concluded that combining the texture parameters, enhancement pattern and VEGFR could significantly improve the predictive performance of ER.

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Radiomics analysis of gadoxetic acid-enhanced MRI for the evaluation of HCC treatment response to Yttrium-90 radioembolization
Stefanie Hectors1,2, Amy Law1,2, Edward Kiim2, Sara Lewis1,2, and Bachir Taouli1,2

1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States

The goal of our study was to assess the predictive value of radiomics features assessed on pre-treatment multi-phasic gadoxetic acid-enhanced (EOB-)MRI for prediction of response of hepatocellular carcinoma to 90Yttrium radioembolization (RE). We found that radiomics features measured at baseline were predictive of response assessed at 6 weeks and 6-12 months after treatment. These results indicate value of radiomics for prediction of RE response, which needs to be validated in a larger study. 

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Features of Preoperative Dynamical Contrast Enhanced 3-T MR Imaging Predicting Early Recurrence for Small (< 3 cm) Hepatocellular Carcinomas after Curative Resection
Linqi Zhang1, Jingbiao Chen1, Sichi Kuang1, Yao Zhang1, Bingjun He1, Hao Yang1, Ying Deng1, Yuanqiang Xiao1, Kritisha Rajlawot1, Kathryn Fowler2, Jin Wang1, and Claude B. Sirlin2

1Department of Radiology, The third affiliated hospital of Sun Yat-sen University, Guangzhou, China, 2Department of Radiology, University of California at San Diego, La Jolla, CA, United States

Small hepatocellular carcinoma (sHCC, < 3 cm) is generally thought to have a good prognosis after surgical resection. However, the prognosis of patients with sHCC is still unsatisfactory because of frequent early recurrence (ER, <1 year) after resection. In our series, 30 % of patients with resected sHCC had ER. Preoperative MR imaging features (corona enhancement and irregular tumor margin) were independent predictors for ER after resection of sHCC.

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LI-RADS treatment response criteria for hepatocellular carcinoma after locoregional treatment on contrast-enhanced CT and gadoxetic acid-enhanced MRI: a retrospective validation study using pathologic diagnosis as the reference standard
Sungeun Park1,2, Ijin Joo1, Dong Ho Lee1, Jae Seok Bae1, Jeongin Yoo1, and Joon Koo Han1,2,3

1Department of Radiology, Seoul National University Hospital, Seoul, Korea, Republic of, 2Department of Radiology, Seoul National University College of Medicine, Seoul, Korea, Republic of, 3Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea, Republic of

The liver imaging reporting and data system (LI-RADS) recently introduced a new treatment response algorithm, namely LI-RADS treatment response (LR-TR), for HCCs treated with locoregional therapy. Using pathologic tumor viability as the reference standard, our study showed that LR-TR viable category resulted in sensitivities of 67.3%/74.5% on CT and 75.5%/80.9% on Gd-EOB-MRI; and specificities of 88.6%/88.6% on CT and 80.0%/82.9% on Gd-EOB-MRI, in reviewers 1/2, respectively, which were not significantly different between CT and Gd-EOB-MRI. In addition, our modified TR criteria applying MRI ancillary features demonstrated significantly higher sensitivity (83.6%/88.2%) and comparable specificity (80.0%/77.1%) than LR-TR on CT or MRI.

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Gadoxetic acid-enhanced Liver MR can predict tumor recurrence after curative treatment for small single hepatocellular carcinoma
Dong Ho Lee1 and Jeong Min Lee2

1Radiology, Seoul National University Hospital, Seoul, Korea, Republic of, 2Seoul National University Hospital, Seoul, Korea, Republic of

Non-smooth tumor margins and the presence of non-hypervascular HBP hypointense nodules were demonstrated to be independent significant predictive factors of tumor recurrence after either hepatic resection or RFA.

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Can hepatocellular carcinoma surveillance be performed annually instead of every 6 months in at-risk patients with a negative initial MRI examination?
Islam Hamza Zaki1, Benjamin Wildman-Tobriner1, Rajan Gupta1, Rendon Nelson1, and Mustafa Bashir1

1Diagnostic Radiology, Duke University, Durham, NC, United States

This retrospective study investigated the frequency and timing of development of significant hepatic lesions in patients at risk for HCC undergoing surveillance with an initially negative MRI. Out of 70 patients with an initially negative MRI who had mean follow-up of 36 months (range 12-60 months) by contrast-enhanced CT or MRI, no patients developed positive follow up at 1 year.  One patient developed a low-risk LI-RADS 3 lesion at 24 months. It may be reasonable to extend the surveillance interval from six months to 12 months in such patients when the first screening examination is negative.

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Detection of Portal Vein Thrombosis in Patients with Hepatocellular Carcinoma: Can Gadoxetic Acid–enhanced MR Imaging Replace CT?
Jae Seok Bae1, Jeong Min Lee1, Jeong-Hee Yoon1, Siwon Jang1, Jin Wook Chung1, and Joon Koo Han1

1Seoul National University Hospital, Seoul, Korea, Republic of

Gadoxetic acid-enhanced magnetic resonance imaging (GA-MRI) provides higher sensitivity for the detection of HCCs than CT or MRI using extracellular contrast media, but may have a disadvantage in detection of portal vein thrombosis (PVT) related with decreased contrast between the portal vein and liver parenchyma during dynamic phase. For detection of PVT in patients with HCC, we demonstrated that GA-MRI was noninferior to CT for sensitivity (78.8% versus 77.7%, respectively) and was superior to CT for specificity (95.4% versus 92.4%, respectively). For characterization of the PVT as benign or malignant, the GA-MRI showed noninferior accuracy to CT (93.7% versus 92.4%).  

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Comparison of Diagnostic Values of Mono-exponential, Bi-exponential, and Stretched Exponential Diffusion-weighted Magnetic Resonance Imaging in Differentiating Benign and Malignant Hepatic Lesions
Yoshifumi Noda1, Satoshi Goshima1, Kimihiro Kajta1, Yuta Akamine2, Masatoshi Honda2, Tomoyuki Okuaki2, Hiroshi Kadohara2, Nobuyuki Kawai1, Hiroshi Kawada1, Yukichi Tanahashi1, and Masayuki Matsuo1

1Radiology, Gifu University, Gifu, Japan, 2Philips Healthcare, Tokyo, Japan

Intravoxel incoherent motion, a bi-exponential model of diffusion-weighted imaging with multiple b values, can represent pure molecular diffusion and perfusion, and be used in characterizing focal hepatic lesions. Recently, stretched exponential model has been used in glioblastoma and prostate cancer. In this study, we evaluated the feasibility of stretched exponential model for differentiating benign and malignant hepatic lesions. Our results showed that DDC value from a stretched exponential model was the highest diagnostic potential, so it could be a quantitative imaging biomarker for differentiating benign and malignant hepatic lesions.

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Agreement of MRI Liver Observations Size Measurements and Impact on LIRADS v2017 categories (Determinant of size variability and Impact on LI-RADS v2017 category code)
Heejin Kwon1, Yong Eun Chung2, Min-Jeong Kim3, Sang Won Kim4, Guilherme M Cunha5, Tanya Wolfson5, and Claude B Sirlin5

1Dong-A University Hospital, Busan, Korea, Republic of, 2Yonsei University College of Medicine, Severance Hospital, Seoul, Korea, Republic of, 3Hallym University Sacred Heart Hospital, Anyang, Korea, Republic of, 4Kyung Hee University Hospital at Gangdong, Seoul, Korea, Republic of, 5Liver Imaging Group, UCSD Medical center, San Diego, CA, United States

While intra- and inter-observer agreement rates for size measurement is“excellent” for radiologists, variability across imaging phases could potentially impact LI-RADS categorization. Measurement variations were mostly seen across different postcontrast dynamic phases, as well as, related to specific imaging features (eg, presence of APHE and/or a capsule). In our opinion, the standardization of the most adequate imagingphase to perform size measurements of focal liver observations may increase thereproducibility of LI-RADS categories.

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A comparative study of MR elastography and intravoxel incoherent motion based on volumetric analysis in the evaluation of histological grade of Hepatitis B virus-related hepatocellular carcinoma
Qungang Shan1, Yao Zhang1, Tianhui Zhang1, Bingjun He1, Sudhakar K Venkatesh2, Bing Wu3, Kevin J Glaser2, Richard L Ehman2, and Jin Wang1

1Radiology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China, 2Department of Radiology, Mayo Clinic, Rochester, Armenia, 3MR Research China, GE Healthcare, Beijing, China

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver. Poorly differentiated HCC is associated with higher recurrence and worse survival compared with well and moderately differentiated HCC and preoperative prediction of histological grade is useful for deciding treatment strategy. We compared the value of MR elastography (MRE) and intravoxel incoherent motion (IVIM) in predicting the histological grade of hepatitis B virus (HBV)-related HCCs using volumetric analysis. Our results demonstrated that only mean tumor stiffness, and not ADC or IVIM metrics, could predict the histological grade of HCCs.

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Comparison of MR elastography and intravoxel incoherent motion for the prediction of hepatocellular carcinoma tumor capsule formation in hepatitis B virus-related patients using whole-tumor analysis
Yao Zhang1, Qungang Shan1, Sichi Kuang1, Bingjun He1, Jingbiao Chen1, Bing Wu2, Tianhui Zhang1, Ying Deng1, Kevin J Glaser3, Sudhakar K Venkatesh3, Richard L Ehman3, and Jin Wang1

1Department of Radiology, The third affiliated hospital of Sun Yat-sen University, Guangzhou, China, 2MR Research China, GE Healthcare, Beijing, China, 3Department of Radiology, Mayo Clinic, Rochester, MN, United States

Hepatocellular carcinoma (HCC) is the most common primary malignant hepatic tumor worldwide and the prognosis remains poor. Tumor capsule formation is a favorable factor for predicting invasiveness and prognosis. We explored the potential value of MR elastography(MRE)and intravoxel incoherent motion(IVIM)for the prediction of tumor capsule formation in patients with hepatitis B virus-related (HBV) HCCs using whole-tumor analysis. Results showed that mean tumor stiffness may be useful for the prediction of capsule formation of HCCs. The utility of the mean value of IVIM metrics may need to be further explored.

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Metabolic biomarkers associated with occurrence of hepatocellular carcinoma in patients with liver cirrhosis: in vivo 1H magnetic resonance spectroscopy
Chung Man Moon1,2, Sang Soo Shin2,3, Yong Yeon Jeong2,4, and Suk Hee Heo2,4

1National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States, 2Radiology, Chonnam National University Medical School, Gwangju, Korea, Republic of, 3Radiology, Chonnam National University Hospital, Gwangju, Korea, Republic of, 4Radiology, Chonnam National University Hwasun Hospital, Gwangju, Korea, Republic of

Liver cirrhosis (LC) secondary to chronic hepatitis can lead to serious complications. More severely, liver cirrhotic patients may eventually develop hepatocellular carcinoma (HCC), thus monitoring disease progression is clinically important. The purpose of this study was to investigate the utility of 1H magnetic resonance spectroscopy (1H-MRS) with long echo time to quantify the differences in hepatic metabolites of normal, cirrhotic liver with and without HCC, and HCC. These findings would be helpful for understanding of liver metabolic changes related with developing HCC in the cirrhotic liver.

1700
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Impacts of different b and TE values on quality of 3T diffusion-weighted imaging of the liver using a high gradient magnetic field: feasibility of ultrahigh b value of 3000
Keita Fukushima1, Katsuhiro Sano2, Haruhiko Machida3, Toshiya Kariyasu3, Isao Miyazaki1, Tatsuya Yoshioka1, Sanae Takahashi1, Saori Yuda1, Yuta Shimizu1, Takayuki Yonaha1, Akihito Nakanishi1, Hiroshi Kusahara4, Youhei Matsuoka4, Miho Kitamura4, Takao Yamamoto4, and Kenichi Yokoyama3

1Kyorin University Hospital, Tokyo, Japan, 2Diagnostic Imaging, Saitama medical University International medical Center, Saitama, Japan, 3Kyorin University School of Medicine, Tokyo, Japan, 4CANON MEDICAL SYSTEMS CORPORATION, Otawara, Japan

Diffusion-weighted imaging (DWI) with an ultrahigh b value is expected to improve assessment of tumor cellularity and fluid viscosity in the liver but can decrease signal-to-noise ratio (SNR) of the hepatic parenchyma. A state-of-the-art 3T MR scanner with the maximal gradient magnetic field of 100 mT/m can achieve sufficient SNR on liver DWI even at ultrahigh b value of 3000 with use of short TE. The present study using our original phantom and healthy volunteers shows that use of shorter TE significantly increased the SNR with preserved ADC value on DWI even at ultrahigh b value of 3000.

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The efficacy of coronal ZOOMit diffusion-weighted MR imaging at 3T MRI for differentiation of malignant distal bile duct stricture
Ki Choon Sim1, Beom Jin Park1, Min Ju Kim1, Deuk Jae Sung1, and Na Yeon Han1

1Radiology, Korea University Anam Hospital, Seoul, Korea, Republic of

For the evaluation of distal bile duct, diffusion weighted imaging should be routinely included in MR protocol for detection and differentiation of malignant distal bile duct stricture. If possible, it would be better to be able to acquire images in a coronal plane.

1702
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Noninvasive evaluation of the pathologic grade of hepatocellular carcinoma using MCF-3DCNN: A pilot study
Da-wei Yang1,2, Xiao-pei Wang1, Zheng-han Yang1, Zhen-chang Wang1, and Xi-bin Jia3

1Beijing friendship hospital, Capital medical university, Beijing, China, 2Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Beijing, China, 3Beijing University of Technology, Beijing, China

This pilot study indicated that the MCF-3DCNN model may be valuable for the noninvasive evaluation of the pathologic grade of HCCs; however, further improvement would be necessary to achieve a better diagnostic performance for moderately and poorly differentiated HCCs.

1703
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Volume-wise lesion detection on hepatic hemangioma and cyst considering inter-slice information through a 3D convolutional neural network
Yajing Zhang1 and Qitong Hu2

1Philips Healthcare, Suzhou, China, 2Beijing Longleding Medical Technology Co., Ltd., Beijing, China

MR has been widely used for the diagnosis of hepatic hemangioma and cyst due to its significance of detection on small lesions. This study proposes a deep learning based method to detect the lesion volume in a three-dimensional manner on the dynamic contrast-enhanced MR images with hemangioma and/or cyst lesions. The results show good alignment of automated detection contour with the manually labelled lesion contour by professional radiologists, as well as accurate classification of lesion types.  

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Abdominal Diffusion-Weighted Imaging with Stretched-Exponential Model: Phantom and Clinical Studies
Takeshi Yoshikawa1, Yoshiharu Ohno1,2, Seiya Kai3, Masao Yui3, Yoshimori Kassai3, Ryuji Shimada4, Katsusuke Kyotani4, and Shinichiro Seki1

1Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan, 2Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, 3Canon Medical Systems Corporation, Otawara, Japan, 4Kobe University Hospital, Kobe, Japan

Abdominal DWI with stretched-exponential model was assessed in phantom and clinical studies. Our results suggest it is a useful tool for evaluating abdominal organs and diseases.

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The Diagnostic Performance of LI-RADS version 2018 and the Value of Ancillary Features Favoring Hepatocellular Carcinoma (HCC) in the Diagnosis of 10-19 mm HCC on Extracellular Contrast-enhanced MRI.
Jingbiao Chen1, Sichi Kuang1, Bingjun He1, Yao Zhang1, Hao Yang1, Ying Deng1, Kathryn Fowler2, Jin Wang1, and Claude B. Sirlin2

1Department of Radiology, The third affiliated hospital of Sun Yat-sen University, guangzhou, China, 2Department of Radiology, University of California at San Diego, La Jolla, CA, United States

Hepatocellular carcinoma (HCC) is the second most cause of cancer death worldwide. Early detection of small HCC can prolong patient survival. Recent updates have changed diagnostic criteria for LI-RADS v2018 for 10-19 mm HCC, and the impact on accuracy has not yet been studied. We found that LI-RADS v2018 provides 68.2% sensitivity, 91.7% specificity, and 71.8% accuracy for 10-19 mm HCC diagnosis in a Chinese population with chronic liver disease. Several modifications of LI-RADS were explored (e.g., pooling LR-4 and LR-5; allowing ancillary features favoring HCC to upgrade LR-4 to LR-5 and/or convert LR-M to LR-5), some sensitivities were mild improved without specificities increase.


AI & Radiomics in Body MRI

Exhibition Hall
Monday 13:45 - 14:45
 Body: Breast, Chest, Abdomen, Pelvis

1706
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Improved, rapid fetal-brain localization and orientation detection for auto-slice prescription
Malte Hoffmann1,2, Esra Abaci Turk3,4, Borjan Gagoski2,3, Paul Wighton1, M Dylan Tisdall5, Martin Reuter1,2,6, Elfar Adalsteinsson4,7, P Ellen Grant2,3, Lawrence L Wald1,2, and André J W van der Kouwe1,2

1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 2Department of Radiology, Harvard Medical School, Boston, MA, United States, 3Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA, United States, 4Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 5Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, 6German Center for Neurodegenerative Diseases, Bonn, Germany, 7Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States

MRI has become an invaluable tool for assessing the development of the fetal brain and can remove diagnostic doubt after routine ultrasound exams. Motion between slice prescription and acquisition, however, poses a challenge to obtaining images aligned with the standard anatomical planes, essential for evaluating morphometry. To address this, we recently presented automated slice prescription for fetal-brain MRI based on registration to a template. Here, we propose improved and fully automated fetal-brain orientation detection to advance both reliability and speed. The fast estimation is achieved by localizing the brain and eyes in an EPI scout using blob detection techniques.

1707
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Discrimination of Malignant and Benign Breast Lesions Using Machine Learning on Non-Gaussian Diffusion MRI Parameters
Muge Karaman1,2, Yangyang Bu3,4, Zheng Zhong1,2, Shiwei Wang3,4, Changyu Zhou3,4, Weihong Hu3,4, Mark Balich1, Maosheng Xu3,4, and Xiaohong Joe Zhou1,2,5

1Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, IL, United States, 2Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 3The First Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China, 4Department of Radiology, The 1st Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China, 5Departments of Radiology and Neurosurgery, University of Illinois at Chicago, Chicago, IL, United States

Breast cancer is the second leading cause of cancer death among women in the US. Recognizing the complexity of cancerous tissue, several non-Gaussian diffusion MRI models, such as the continuous-time random-walk (CTRW) model, were suggested to probe the underlying tissue environment. In this study, we employed a support-vector-machine-based analysis on the histogram features of CTRW model parameters to differentiate malignant and benign breast lesions. This multi-parameter multi-feature approach provided the best diagnostic performance compared to the conventional single-parameter or single-feature analysis techniques. The combination of machine-learning with non-Gaussian diffusion MRI can facilitate comparable diagnostic performance to that of dynamic-contrast-enhanced MRI.

1708
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A Two-Center Analysis of Hyperpolarized 129Xe Lung MRI in Stable Pediatric Cystic Fibrosis: Comparison of Image Analysis Approaches
Marcus J. Couch1,2, Robert Thomen3, Felix Ratjen1,4, Jason Woods5, and Giles Santyr1,2

1Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3School of Medicine, University of Missouri, Columbia, MO, United States, 4Division of Respiratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada, 5Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States

The ventilation defect percent (VDP), measured from hyperpolarized 129Xe MRI, is sensitive to functional changes in early cystic fibrosis (CF) lung disease; however, there is no consensus on which VDP calculation method is most appropriate for future multi-center clinical trials in CF. This study compared VDP analysis methods in hyperpolarized 129Xe datasets acquired in stable pediatric CF subjects at two institutions. In a combined dataset, a comparison of k-means, mean-anchored linear binning, and 99th percentile-anchored linear binning demonstrated that all three methods provide a good characterization of the disease, but mean-anchored linear binning provided the strongest correlation to pulmonary function tests.

1709
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Partial velocity-compensated optimized diffusion encoding for combined motion compensation and residual vessel signal suppression in liver ADC mapping
Sean McTavish1, Anh Tu Van1, Johannes Peeters2, Tetsuo Ogino3, Andreas Hock4, Ernst Rummeny1, Rickmer Braren1, and Dimitrios Karampinos1

1Technical University of Munich, Munich, Germany, 2Philips Healthcare, Best, Netherlands, 3Philips Healthcare, Tokyo, Japan, 4Philips Healthcare, Hamburg, Germany

Despite its strong clinical significance in lesion detection and tumor staging, liver DWI remains challenged by its strong sensitivity to motion effects. Motion-compensated diffusion encoding schemes have recently been proposed to improve DW liver signal homogeneity especially in the left liver lobe, a region typically affected by cardiac motion. However, motion-compensated diffusion encoding is associated with hyperintense vessel signal even at high b-values, which can obscure lesion detection. The present work proposes a partial velocity-compensated diffusion encoding using asymmetric diffusion gradients for combined motion compensation and residual vessel signal suppression in liver DWI, optimized for short echo times.

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Characterization of sub 1 cm Breast Lesions using Radiomics Analysis
Peter Gibbs1, Natsuko Onishi1, Meredith Sadinski1, Elizabeth Morris1, and Elizabeth Sutton1

1Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States

DCE MRI of breast lesions has high sensitivity (>90%) and reasonable specificity (>70%). However, the specificity for smaller lesions is known to be poorer due to the inability to confidently distinguish morphological and kinetic features. This work utilizes radiomics of model free parameter maps to improve the diagnostic accuracy of sub 1cm lesions with a PPV of 100% and a NPV of 91% obtained in a test dataset. The high level of correlation between texture features calculated from initial enhancement, overall enhancement, and area under the enhancement curve maps indicate that data acquisition beyond peak enhancement may be unnecessary.


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Automatic prostate and prostate zones segmentation of magnetic resonance images using convolutional neural networks
Nader Aldoj1, Federico Biavati1, Miriam Rutz1, Sebastian Stober2, and Marc Dewey1

1Charite, Berlin, Germany, 2University of potsdam, Berlin, Germany

The purpose was to develop a fully automatic and accurate tool for prostate and prostate zone segmentation using T2-weighted MRI. Thus, we developed a new neural network named Dense U-Net which was trained on 143 patient datasets and tested on 45 patient datasets. This Dense U-Net compared with the state-of-the-art U-Net achieved an average dice score for the whole prostate of 89.4±0.8% vs. 88.4±0.8%, for the central zone of 83±0.2% vs. 83±0.2%, and for the peripheral zone of 76.9±0.2% vs. 74.6±0.2%, respectively. In conclusion, the developed Dense U-Net was more accurate than the state-of-the-art U-Net for prostate and prostate zone segmentation.

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Radiomic Characteristics Derived from Diffusion-Weighted Imaging for the Assessment of Breast Cancer Receptor Status and Molecular Subtypes
Doris Leithner1,2, Joao V. Horvat1, Maria Adele Marino1, Daly Avendano1, Sunitha Thakur3, Blanca Bernard-Davila4, Maxine S Jochelson1, Danny F Martinez1, Elizabeth A Morris1, and Katja Pinker1,5

1Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2University Hospital Frankfurt, Frankfurt am Main, Germany, 3Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 4Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 5Medical University of Vienna, Vienna, Austria

To evaluate the diagnostic performance of DWI radiomic signatures for the assessment of breast cancer receptor status and molecular subtypes. Ninety-one patients with breast cancer were included. Lesions were manually segmented on high b-value DWI and propagated to ADC maps. To compare different segmentation approaches a subgroup was directly segmented on the ADC map. Results demonstrate that DWI radiomic signatures enable the assessment of breast cancer receptor status and molecular subtypes with high accuracy. Higher accuracies are achieved when segmentations are performed directly on ADC maps that cancel out T2 shine-through indicating as the preferred approach for radiomic analysis.

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Prediction of stage, differentiation and Ki-67 status of locally advanced cervical cancer by DCE-MRI texture analysis
Xie Yuanliang1, Jiang Yanping1, Wang Xiang1, Du Dan2, Xie Wei2, and Sun Jianqing3

1Radiology, Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 2Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 3Philips Healthcare, Shanghai, China

This retrospective study explored the value of texture analysis in predicting the stage, differentiation and Ki-67 status of pretreatment advanced cervical cancer. Multi-class radiomics feature extraction was performed on the maximum enhancement (ME) and maximum relative enhancement (MRE) maps from DCE-MRI. A prediction model using a machine learning-XGB classifier showed the mean sensitivities of predicting FIGOⅡb-Ⅲa, poor differentiation and high Ki-67 status were 0.767, 0.963 and 0.967; specificities were 0.958, 0.361 and 0.694 , and AUCs were 0.910, 0.920 and 0.840 respectively. DCE-MRI textural parameters have potential as non-invasive imaging biomarkers in predicting histopathology in advanced cervical cancer.

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Prediction molecular subtypes of Breast Cancer by MRI Radiomics
Shuangyan Sun1, Dingli Ye2, Changliang Yang3, Jianqing Sun4, and Jihong Zhao2

1Radiology, JiLin Cancer Hospital, ChangChun, China, 2Radiology, Jilin Cancer Hospital, ChangChun, China, 3Thoracic Oncology, Jilin Cancer Hospital, ChangChun, China, 4Philips Healthcare, shanghai, China

Breast cancer molecular subtypes are indicators of disease free and overall survival. This study aimed to investigate whether quantitative radiomic features extracted from MRI images are associated with molecular subtypes of breast cancer. 135 women diagnosed with invasive breast cancer were enrolled and divided into 3 groups as follow: triple-negative vs non–triple-negative, HER2-enriched vs non–HER2-enriched, and luminal (A + B) vs nonluminal. A machine learning scheme was employed for the classification. The mean AUC of the three models are 0.76, 0.85 and 0.73, respectively. There is a moderate association between tumour molecular biomarkers and radiomic features extracted from MRI images.

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Fully Automated Segmentation of Cervical Cancer in Diffusion MR Imaging Using U-Net Convolutional Neural Networks
Yu-Chun Lin1,2, Chia-Hung Lin1, Hsin-Ying Lu1, Ho-Kai Wang1, Su-Han Ng1, Jiunjie Wang2, and Gigin Lin1

1Dept. Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan, 2Dept. Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan, Taiwan

The aim of the study is to evaluate the performance of U-Net in tumor segmentation on diffusion MR imaging for patients with cervical cancer. Diffusion weighted imaging of b0, b1000 and ADC maps were used for training. The ADC histogram parameters of predicted region of tumor were assessed for accuracy and reproducibility. The results show the triple-channel training algorithm exhibited the best performance in both training and testing datasets. The predicted voxels of tumor can be used to generate the volumetric ADC data for Radiomics study.

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Texture Analysis based on functional magnetic resonance imaging for evaluation of renal function
Gumuyang Zhang1, Hao Sun1, Jianfeng Sun2, Hailong Zhou1, Yanhan Liu1, Ning Guo2, Jing An3, Huadan Xue1, and Zhengyu Jin1

1Peking Union Medical College Hospital, Beijing, China, 2Philips Healthcare, Shanghai, China, Beijing, China, 3MR Collaboration, Siemens Healthcare Ltd, Beijing, China, Beijing, China

Texture analysis (TA) based on apparent diffusion coefficient (ADC), T1 and T2 mapping to evaluate glomerular filtration rate (GFR) has not been explored before. A total of 116 participants underwent DWI, T1 and T2 mapping of both kidneys on a 3T MR scanner and texture features were measured for the cortex and medulla of each kidney. Models incorporating texture features mainly quantified from ADC and T1 maps produced a satisfactory performance for detecting abnormal renal function and characterizing the different severity of GFR decline. It’s promising that TA based on ADC and T1 maps could serve as imaging markers to evaluate renal function. 

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Evaluation of Variable-TE computed Diffusion Weighted Imaging Technique using Deep Learning based Noise Reduction
Hiroshi Kusahara1, Yuki Takai1, Kensuke Shinoda1, and Yoshimori Kassai1

1MRI development department, Canon Medical Systems Corporation, Tochigi, Japan

In this study to the authors adapted the variable-TE cDWI(vTE-cDWI) technique applying denoise approach with deep learning reconstruction(dDLR) to the abdominal region, using ADC-map, T2-map and T1-map with IR-based images. The algorithm under evaluation allows computing diffusion images for arbitrary combinations of TE, b-value and TI based on four acquisitions(4-points method). This technique was shown to generate vTE-cDWI with higher SNR compared to the acquired DWI, and dDLR increased the SNR more, as well as obtain ADC-maps and T1-maps with optimal TI for any arbitrary tissue. The clinical benefits of the method and results on volunteers are discussed.

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Automatic breast lesion segmentation in MR images employing a dense attention fully convolutional network
Cheng Li1, Hui Sun2, Qiegen Liu3, Zaiyi Liu4, Meiyun Wang5, Hairong Zheng1, and Shanshan Wang1

1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2School of Control Science and Engineering, Shandong University, Shangdong, China, 3Department of Electronic Information Engineering, Nanchang University, Nanchang, China, 4Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China, 5Henan Provincial Peoples Hospital, Henan, China

Despite its high sensitivity, MR imaging has low specificity and high false positive issues. Therefore, automatic breast lesion detection algorithms are necessary. To this end, we propose a new network, dense attention network (DANet), for breast lesion segmentation in MR images. In DANet, we designed a feature fusion and selection mechanism. Features from the corresponding encoder layer and from all previous decoder layers are fused by concatenation. To highlight the rich-informative channels, a channel attention module is introduced. DANet showed better segmentation results compared to commonly applied segmentation networks on our 2D contrast-enhanced T1-weighted breast MR dataset.

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Deep Learning off-resonance correction for faster free-breathing contrast-enhanced conical ultrashort echo time (UTE) MRI of the pelvis
Signy Holmes1, David Zeng2, Joseph Y Cheng1, Marcus T Alley1, Michael Carl3, Dwight Nishimura2, Preeti A Sukerkar1, Vipul R Sheth1, Ryan Brunsing1, and Shreyas S Vasanawala1

1Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States, 3Applied Science Laboratory, GE Healthcare, San Diego, CA, United States

MRI sequences with 3D cones k-space trajectories allow decreased motion artifacts while achieving ultrashort echo times (UTE). Extending readout durations allows decreased scan times but lead to worsening off-resonance artifacts. We assessed the performance of extended-readout, free-breathing UTE 3D cones MRI with and without a deep learning off-resonance correction in the evaluation of the adult pelvis. UTE imaging performed significantly better than 3D Cartesian spoiled gradient echo (SPGR) in noise, and after off-resonance correction also performed significantly better in artifact reduction.  

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Deep Learning Assisted Fully Automatic Post-Processing for Quantitative Lung MRI
Andreas Max Weng1, Christian Kestler1, Andreas Steven Kunz1, Simon Veldhoen1, Thorsten Alexander Bley1, Herbert Köstler1, and Tobias Wech1

1Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany

Functional lung MRI still suffers from a time consuming post-processing with manual image segmentation being its most time consuming part. We introduce and evaluate a deep learning based semantic image segmentation technique to enable fully automated post-processing in SENCEFUL-MRI. Obtained segmentations were compared to manual segmentations using the DICE similarity coefficient (DSC). Furthermore, quantitative ventilation values were obtained after manual and automatic segmentation. Mean DSC of the binary segmentation masks was 0.83 ± 0.09 and no significant difference in quantitative ventilation values was observed. Obtained results show that the time consuming manual post-processing in functional lung MRI can be automated by the proposed neural network.

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A task-based endpoint assessment for CNN segmentations in radiomics processing
Karl Spuhler1, Jie Ding1, Mario Serrano-Sosa1, and Chuan Huang1,2,3

1Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 2Radiology, Stony Brook Medicine, Stony Brook, NY, United States, 3Psychiatry, Stony Brook Medicine, Stony Brook, NY, United States

In this study, we present evidence that CNN-based segmentations are sufficient for automated ROI delineation in radiomics processing.

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Validation of Radiomics Signature for Chemoradiotherapy Prediction of Advanced Cervical Cancer Based on a High Resolution T2WI Images
Defeng Liu1, Qinglei Shi2, Xu Yan2, Lanxiang Liu1, Yujie Cui1, Xiaohang Zhang3, and Juan Du4

1Qinhuangdao Municipal No. 1 Hospital, Qinhuangdao, China, 2MR Scientific Marketing, Siemens Healthcare, Qinhuangdao, China, 3University of Chinese Academy of Sciences, Beijing, China, 4Graduate School of Hebei Medical University, Shijiazhuang, China

This study performed a radiomics signature analysis based on a high resolution T2WI images, and evaluate the value of these quantitative features in prediction the treatment effect of neoadjuvant chemotherapy-radiation therapy for advanced cervical cancer (>IIb) . And found that Shape and first-order features seems can provide valuable information and showed potential in prediction treatment effect of this disease.

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Predicting Pathological Response to Neoadjuvant Chemotherapy Using 3D Texture Feature Radiomics on Baseline Dynamic Contrast-Enhanced (DCE) MRI
Yifan Wu1, Daniel S. Hippe1, Ginger L. Lash1, Lanell M. Peterson1, Jennifer M. Specht2, and Savannah C. Partridge1

1Radiology, University of Washington, Seattle, WA, United States, 2Medicine, University of Washington, Seattle, WA, United States

There is emerging data supporting the value of texture and other radiomics features extracted from dynamic contrast-enhanced (DCE) MRI to characterize breast cancer subtypes and recurrence risk. DCE texture features may also provide unique value in predicting response to neoadjuvant chemotherapy (NAC). Our study investigated the predictive value of pretreatment DCE tumor texture features in 30 women with triple negative and luminal-B cancers undergoing NAC. We found higher-order texture features significantly predicted pathologic response, while other standard quantitative metrics did not. Our findings suggest texture features on DCE MRI may provide valuable information prior to treatment to help tailor therapies.

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Application research on 3D texture analysis technology based on MRI in the identification of molecular subtypes of breast cancer
Dingli Ye1, Shuangyan Sun2, Jianqing Sun3, and Jihong Zhao4

1Radiology, JiLin Cancer Hospital, ChangChun, JiLin Province, China, 2JiLin Cancer Hospital, ChangChun,JiLin Province, China, 3Philips Healthcare, Shanghai, China, 4JiLin Cancer Hospital, ChangChun, JiLin Province, China

    The purpose of this work was to use radiomics features to build a classification model that can classify breast cancer into different molecular subtypes. Our result shows that some radiomics features have great potential to be an useful index in predicting the subtype of breast cancer, therefore providing helps for the development of clinical treatment decisions for breast cancer.

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Deep Learning Model for Liver MRI Segmentation
Amber Michele Mittendorf1, Lawrence Ngo1, Erol Bozdogan1, Mohammad Chaudhry1, Steven Chen1, Gemini Janas1,2, Jacob Johnson3, Zhe Zhu1, Maciej Mazurowski1, and Mustafa R Bashir1,2,4

1Department of Radiology, Duke University Medical Center, Durham, NC, United States, 2Center for Advanced Magnetic Resonance Imaging, Duke University Medical Center, Durham, NC, United States, 3Department of Radiology, University of Wisconsin, Madison, WI, United States, 4Department of Medicine, Gastroenterology, Duke University Medical Center, Durham, NC, United States

Hepatic segmentation is an important but tedious clinical task used in a variety of applications.  Existing techniques are relatively narrow in scope, requiring a particular type of MRI sequence or CT for accurate segmentation.  We developed a Convolutional Neural Network (CNN) capable of automated liver segmentation on single-shot fast spin echo, T1-weighted, or opposed phase proton-density (OP-PD) weighted sequences using separate training/validation and testing data sets.  Compared to human segmenters, the CNN performed well, with volumetric DICE coefficients of 0.92-0.95.  The CNN performed least consistently on OP-PD sequences, which had the smallest number of cases in the training/validation data set. 

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Deep-Learning-Based Denoising of Diffusion-Weighted Prostate Images
Elena Kaye1, Yousef Mazaheri1, Maggie Fung2, Ross Schmidtlein1, Ricardo Otazo1, Oguz Akin3, and Herbert Alberto Vargas3

1Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2GE Healthcare, New York, NY, United States, 3Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States

Despite its unique capabilities, diffusion-weighted imaging (DWI) in prostate is inherently limited by low signal-to-noise ratio (SNR). Currently, gains in SNR of high b-value images are achieved through increase in the number of excitations (NEX), at the cost of increase in total acquisition time. We demonstrate feasibility of improving prostate DWI image quality by leveraging denoising convolutional network. Using pairs of "noisy" NEX4 and "clean" NEX16 DWI images, reconstructed from raw data, CNN was trained to denoise prostate DWI images. Denoising of images significantly improved SNR and increased overall image quality, reviewed by two experienced genitourinary radiologists. 

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The associations between breast density and the radiomic features derived from T1-weighted MRI
Jie Ding1, Karl Spuhler1, Mario Serrano Sosa1, Alison Stopeck2,3, Patricia Thompson2,4, and Chuan Huang1,2,5,6,7

1Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 2Stony Brook University Cancer Center, Stony Brook, NY, United States, 3Hematology and Oncology, Stony Brook Medicine, Stony Brook, NY, United States, 4Pathology, Stony Brook Medicine, Stony Brook, NY, United States, 5Radiology, Stony Brook Medicine, Stony Brook, NY, United States, 6Computer Science, Stony Brook University, Stony Brook, NY, United States, 7Psychiatry, Stony Brook Medicine, Stony Brook, NY, United States

Breast density (BD) has been recognized as a biomarker of breast cancer risk. We previously developed a highly reproducible MRI-based BD measurement (MRD), that is directly comparable to mammographic density, using fat-water decomposition MRI to assess the breast cancer risk in clinical trials. However, this method requires a specific sequence which cannot be applied to previously acquired data. In this work, we investigate possibility of using the radiomic features extracted from routine T1-weighted MRI to represent MRD. This finding enables a possibility of evaluating the breast cancer risk using the routine MRI data in clinical practice.

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A Real-Time Centralized Pipeline for Reconstructing and Quantifying Hyperpolarized 129Xe Gas Exchange MRI
Ziyi Wang1, Mu He2, Alexander Culbert1, John Nouls3, Elianna A Bier1, and Bastiaan Driehuys1,3

1Biomedical Engineering, Duke University, Durham, NC, United States, 2Electrical and Computer Engineering, Duke University, Durham, NC, United States, 3Radiology, Duke University Medical Center, Durham, NC, United States

Hyperpolarized 129Xe MRI is emerging as a powerful means to provide 3D quantitative mapping of ventilation, interstitial barrier uptake, and red blood cell transfer. However, this capability requires non-standard radial reconstruction and accurate lung segmentation to enable quantitative analysis. Such reconstruction and image processing would ideally be standardized and centralized to facilitate using 129Xe gas exchange MRI in multi-center clinical trials. To this end, we developed a neural-network based lung segmentation approach that automatically generates accurate masks. With this capability, we demonstrate a fully centralized processing pipeline for real-time reconstruction and quantitative reporting of 129Xe gas exchange MRI.

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Proton density fat fraction results derived from deep learning auto-segmentation correlate strongly with results obtained by manual analysis
Ashley L. Louie1, Kang Wang1, Timoteo Delgado1, Michael S. Middleton1, Gavin Hamilton1, Tanya Wolfson2, Robert P. Myers3, C. Stephen Djedjos3, Rohit Loomba4, and Claude B. Sirlin1

1Liver Imaging Group, Department of Radiology, University of California San Diego, La Jolla, CA, United States, 2Computational and Applied Statistics Laboratory (CASL), SDSC, University of California San Diego, La Jolla, CA, United States, 3Gilead Sciences, Inc., Foster City, CA, United States, 4NAFLD Research Center, Division of Gastroenterology, University of California San Diego, La Jolla, CA, United States

A widely-accepted method to estimate hepatic proton-density fat fraction (PDFF) is by averaging values derived from manually drawn regions-of-interest (ROIs) in the nine Couinaud segments. An automated deep-learning-based segmentation tool has been developed to potentially replace this labor-intensive and technically-challenging method. The purpose of this study was to compare whole-liver PDFF values obtained using this auto-segmentation tool to results obtained using manual analysis for a longitudinal multi-center clinical trial of 72 patients with nonalcoholic steatohepatitis. We found that PDFF values estimated using the auto-segmentation tool were in near agreement with values derived by manually drawing ROIs.

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Automated Assessment of Liver Parenchymal Enhancement on Hepatobiliary Phase MR Images Using a Convolutional Neural Network
Guilherme Moura Cunha1, Kyle A Hasenstab1, Kang Wang1, Timo Delgado1, Atsushi Higaki1, Ryan L Brunsing2, Alex Schlein1, Armin Schwartzman3, Albert Hsiao1, and Claude B Sirlin1

1Radiology, University of California San Diego, La Jolla, CA, United States, 2Radiology, Stanford University, Palo Alto, CA, United States, 3Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, United States

Adequate hepatocellular enhancement (HCE) in Gd-EOB-DTPA-enhanced MRI studies can often deviate from the standard delay of 20 minutes. In this study, we proposed a fully-automated CNN-based approach for real-time assessment of HCE adequacy and retrospectively evaluated performance using 1201 T1w HBP 3D image sets from 406 unique patients. Our proposed model classified images with inadequate uptake with an AUC of 97%. With further validation, this approach could be used to identify the earliest time point HCE adequacy is achieved, potentially shortening scanning time by tailoring the exam length to the individual liver’s ability to uptake contrast.


Liver Fibrosis

Exhibition Hall
Monday 13:45 - 14:45
 Body: Breast, Chest, Abdomen, Pelvis

1731
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A virtual liver biopsy based on mixed MRI radiomics and biological data: a proof of concept
Benjamin Leporq1, Sophie Gaillard1, Liadeh Cuminal2, Valerie Hervieu3, Olivier Guillaud4, Jerome Dumortier4, Pierre-Jean Valette5, and Olivier Beuf1

1CREATIS CNRS UMR 5220; Inserm U1206; INSA-Lyon; UCBL Lyon 1, Université de Lyon, Villeurbanne, France, 2Department of Radiology, CHU Edouard Herriot, Lyon, France, 3Department of Pathology, CHU Edouard Herriot, Lyon, France, 4Department of Hepato-Gastro-Enterology, CHU Edouard Herriot, Lyon, France, 5Department of Radiology, CHU Lyon Sud, Lyon, France

Whereas NASH is associated with poor long-term outcome, widespread screening is not currently feasible given that a definitive diagnosis of NASH can only be made through liver biopsy. In this study, a virtual liver biopsy was developed with machine learning from mixed multiparametric MRI radiomics and biological data.

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Three-dimensional MR Elastography (MRE) can replace 2D MRE in staging liver fibrosis: Noninferiority test of the area under the ROC curve and comparison of image quality.
Hao Yang1, Hezhi Lu2, Yong Liu3, Sichi Kuang1, Bingjun He1, Kevin J Glaser4, Meng Yin4, Sudhakar K Venkatesh4, Bing Wu5, Richard L Ehman4, and Jin Wang1

1Department of Radiology, The third affiliated hospital of Sun Yat-sen University, Guangzhou, China, 2South China Normal University, Guangzhou, China, 3Department of Pathology, The third affiliated hospital of Sun Yat-sen University, Guangzhou, China, 4Department of Radiology, Mayo Clinic, Rochester, MN, United States, 5MR Research China, GE Healthcare, Beijing, China

2D MR elastography (MRE) has been shown to be the most accurate noninvasive technique for the detection and staging of liver fibrosis. Tissue stiffness quantification based on 3D MRE is theoretically more accurate while having comparable diagnostic accuracy for staging fibrosis. Our results showed that the diagnostic performance of 3D MRE is not inferior to 2D MRE in assessing liver fibrosis by using a noninferiority test of the area under the ROC curve based on the restricted maximum likelihood (REML) method. Moreover, 3D MRE had better image quality and has the potential to replace 2D MRE in clinical applications.

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Comparison of Spin-echo Echo-planar imaging (SE-EPI) MR elastography (MRE) and Gradient-recalled echo (GRE) MRE at 3.0T in pediatric nonalcoholic fatty liver disease (NAFLD)
Skorn Ponrartana1, Michael Chiang1, Quin Lu2, Hui Wang2, Tania Mitsinikos3, and Rohit Kohli3

1Radiology, Children's Hospital Los Angeles, Los Angeles, CA, United States, 2Philips Healthcare North America, Gainesville, FL, United States, 3Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, United States

Currently, most MRE performed clinically at 3.0T uses a GRE sequence.  However, recent literature describes susceptibility effects from fat that may confound MRE performance, especially at 3.0T.  SE-EPI is a faster technique that is less sensitive to susceptibility artifacts and signal loss and has recently been developed at 3.0T.  In this work, we compare measures of liver stiffness between SE-EPI and GRE MRE techniques in pediatric patients with NAFLD at 3.0T.

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Liver fibrosis detection and staging in rats: a comparative study of T1 relaxation time in the rotating frame block sequence and adiabatic sequence.
Da Shi1, Xianyue Quan1, Yingjie Mei2, Shisi Li3, and Genwen Hu4

1Radiology department, Zhujiang hospital of southern medical university, Guangzhou, China, 2MR clinical science, Philips Healthcare, Guangzhou, China, 3Radiology department, Guangzhou, China, 4Radiology department, Shenzhen people's hospital, Shenzhen, China

Objective: To compare diagnostic performances on staging liver fibrosis of T1 relaxation time in the rotating frame block sequence and adiabatic sequence. Materials and Methods: 65 healthy Sprague Dawley (SD) rats were randomly divided into model and black groups. Block T1ρ and adiabatic T1ρ were performed on the rats with a 3.0-T clinical scanner. Results: T1ρ values were significantly different among stages (P <0.05), except for stages S1 and S2 with block T1ρ. AUC for block T1ρ values were 0.989, 0.924, 0.932 and 0.923, respectively. AUC for Adiabatic T1ρ values were 0.992,0.948,0.967 and 0.963, respectively. Conclusions: Adiabatic T1ρvalues had higher diagnositic performances on staging liver fibrosis in rats. 

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Comparison of native T1 mapping and acoustic radiation force impulse elastography for noninvasively assessing liver fibrosis: repeatability, reproducibility, and staging and monitoring the fibrosis process
Jinning Li1, Huanhuan Liu1, Caiyuan Zhang1, Shuyan Yang1, Yanshu Wang1, Weibo Chen2, Xin Li3, and Dengbin Wang1

1Department of Radiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 2Philips Healthcare, Shanghai, China, 3GE Healthcare, Shanghai, China

To investigate the performances of native T1 mapping for noninvasively assessing liver fibrosis, including repeatability, reproducibility, and staging and monitoring the process of fibrosis, and to compare them with those of acoustic radiation force impulse (ARFI) elastography. The results of our experimental study suggest that native T1 mapping may be a reliable, accurate, and noninvasive tool for assessing liver fibrosis. Compared with ARFI elastography, native T1 mapping is a more robust quantitative technique with similar performances for staging fibrosis. Furthermore, it has a higher accuracy for monitoring liver fibrosis, especially for detecting fibrosis regression.

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The quantitative evaluation of Gd-EOB-DTPA enhanced magnetic resonance imaging T1mapping imaging on liver fibrosis
Tian Qiu1, Yuxin Shi1, and Weibo Chen2

1Shanghai Public Health Clinical Center Affiliated to Fudan University, Shanghai, China, 2Philips Healthcare,Shanghai,China, Shanghai, China

Liver biopsy is an invasive inspection method of staging liver fibrosis,but we study was to evaluate a new procedure by injecting a Gd-EOB-DTPA that hepatobiliary specific contrast to stage the liver fibrosis non-invasively. 

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Evaluation of Fontan Associated Liver Disease (FALD) with MRI: Does cardiac function play a role?
Kathan A Amin1, Liisa Bergmann1, Alejandro Roldan1, Scott B Reeder2, and Christopher J Francois1

1Radiology, University of Wisconsin - Madison, MADISON, WI, United States, 2Radiology, Medical Physics, Biomedical Engineering, Medicine, Emergency Medicine, University of Wisconsin - Madison, MADISON, WI, United States

The Fontan procedure prolongs survival in patients with congenital heart disease with mono-ventricle physiology but is associated with multiple long-term complications, including Fontan associated liver disease (FALD). The pathophysiology of FALD is poorly understood. In this study, the relationship between ventricular ejection fraction (EF) and FALD was investigated through a retrospective review of 24 Fontan patients who underwent cardiac and liver MRI. No correlation was identified between systemic ventricular EF and liver stiffness. This demonstrates the need for further investigation into the pathophysiology of FALD. Potential exploration may include flow related differences, or variations in systemic venous pressures. 

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Quantitative MRI to assess portal hypertension in cirrhosis patients at 3T
Chris R Bradley1,2, Rob E Scott2, Eleanor F Cox1,2, Naaventhan Palaniyappan2, Indra Neil Guha2, Guruprasad P Aithal2, and Susan T Francis1,2

1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 2NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, United Kingdom

We have previously validated MRI as a surrogate measure of Hepatic Venous Pressure Gradient (HVPG) at 1.5T using T1 relaxation time and splanchnic haemodynamics. Here, we explore the use of quantitative 3T MRI to assess portal hypertension. A strong correlation between HVPG and fat suppressed IR SE-EPI T1 (p<0.0001) and a correlation with superior mesenteric artery (SMA) velocity (p=0.02) was observed. MOLLI T1 showed a weak correlation with HVPG (p=0.11) compared with SE-EPI (p<0.001) in a matched patient subset. A fat suppressed IR SE-EPI T1 scheme and SMA velocity can be used as a surrogate for HVPG at 3T.

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The value of hepatocyte fraction based on pharmacokinetic model using gadoxetate disodium in assessment of liver fibrosis stage
En-Ming Cui1, Wan-Sheng Long1, Fan Lin2, Qing Li3, Jun-Hua Wu4, Zhuo-Yong Li1, Yong Lan1, and Ying-Jie Mei5

1Radiology, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun YAT-SEN University, Jiangmen, China, 2Radioogy, The First Affiliated Hospital of Shenzhen University, Health Science Center, Shenzhen Second People's Hospital, Shenzhen, China, 3Pathology, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun YAT-SEN University, Jiangmen, China, 4Hepatobiliary Surgery, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun YAT-SEN University, Jiangmen, China, 5Healthcare, Philips, Guangzhou, China

Liver fibrosis is prevalent in patients with chronic liver disease, and the early diagnosis of liver fibrosis is still challenging in clinical practice. In this study, the hepatocyte fraction (HepF) was calculated using the T1 value before and 20min after Gd-EOB-DTPA injection (hepatobiliary phase). Patients with severe liver fibrosis showed significantly higher T1 value and lower HepF value. In addition, HepF achieved the best performance in differentiation of liver fibrosis from non-fibrosis (AUC = 0.74), and mild liver fibrosis from severe liver fibrosis (AUC = 0.95), proving HepF can be a better noninvasive quantitative method for liver fibrosis evaluation. 

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Texture analysis Using Hepatobiliary Phase Gadoxetic-acid MRI for the Detection of Liver Allograft Fibrosis
Miriam Hulkower1,2, Sara Lewis1,2, Nicholas Vountsinas1, Xing Chin1, Priyanka Kadaba1, Andrew Lee1, Ayushi Singh1, Joseph Song1, Stefanie Hectors1,2, Octavia Bane1,2, Paul Kennedy1,2, Juan Putra3, Swan Thung3, Thomas Schiano4, Maria Isabel Fiel3, and Bachir Taouli1,2

1Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 4Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States

The goal of our study was to assess the value of qualitative and quantitative texture features on gadoxetic-acid enhanced MRI compared to blood tests for the detection of liver allograft fibrosis. We found that quantitative texture analysis and laboratory FIB-4 score exhibited complementary information for prediction of fibrosis stage, while qualitative MRI features were only valuable for identifying advanced fibrosis/cirrhosis.

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A Rapid MR Elastography Sequence with Spatial Saturation Pulses to Suppress Vascular Flow
Hui Wang1,2, Andrew T. Trout2, Jean A. Tkach2, Tom Cull3, Jonathan R. Dillman2, and Charles L. Dumoulin2

1Philips, Cincinnati, OH, United States, 2Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States, 3Philips, Cleveland, OH, United States

We describe a rapid fast field echo (FFE) Magnetic Resonance Elastography (MRE) pulse sequence for measurement of liver stiffness in reduced breath hold times (from 13.3s to 9.2s/slice). The key features of the sequence include: 1) modified motion encoding gradients to allow a shorter TR while maintaining appropriate synchronization with the period of the applied mechanical motion; 2) flow saturation pre-pulses to suppress ascending and descending vascular flow; and 3) SENSE reconstruction. Through validation in a gel phantom and subsequent measurement of liver stiffness in vivo, we demonstrate the effectiveness of the new pulse sequence.

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Building an animal liver fibrosis bioimaging database for the MR imaging severity index establishment: progress report
Yeon Ji Chae1, Chul-Woong Woo2, Sang-Tae Kim2, Young-Jin Kim2, Ji-Yeon Suh2, Ji-heon Kang2, Kyung-Won Kim3, Yoonseok Choi4, and Dong-Cheol Woo1,2

1Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of, 2Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea, Republic of, 3Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of, 4Medical Research Institute, Gangneung Asan Hospital, Gangneung-si, Korea, Republic of

The purpose of this study is to establish the imaging severity index of thioacetamide (TAA)-induced animal liver fibrosis model by magnetic resonance imaging (MRI) techniques.

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Monitoring of antiviral treatment with MR elastography in chronic hepatitis patient: Feasibility study
Yong Eun Chung1, Mi-Suk Park1, Seung Up Kim1, Beom Kyung Kim1, and Myeong-Jin Kim1

1Yonsei University College of Medicine, Seoul, Korea, Republic of

Multi-parametric MR including MR elastography (MRE), IDEAL IQ and diffusion weighted image were performed in patients with chronic liver disease. Among them, 15 patients were treated with antiviral agents which could improve liver fibrosis. In patients who underwent antiviral treatment, liver stiffness measured by MRE after treatment was significantly decreased. Liver stiffness in non-treated group and other MR parameters in both groups were not significantly changed. In conclusion, MRE could be used for the response evaluation of antiviral therapy in patients with chronic hepatitis

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Assessment of Spin-Echo and Gradient-Echo Liver MRE in Healthy Children and Children with Suspected Fibrosis at 3 T
Tess Armstrong1, Sarai G. Santos2, Karrie V. Ly2, Ely Felker1, Shahnaz Ghahremani1, Xinran Zhong1,3, Robert S. Venick2, Joanna Yeh2, Grace Hyun J. Kim1, Kyunghyun Sung1, Kara L. Calkins2, and Holden H. Wu1

1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 2Pediatrics, University of California Los Angeles, Los Angeles, CA, United States, 3Physics and Biology in Medicine IDP, University of California Los Angeles, Los Angeles, CA, United States

Magnetic resonance elastography (MRE) accurately measures liver stiffness and correlates with liver histopathology. However, conventional gradient-echo (GRE) MRE sequences require multiple breath-holds. Spin-echo echo-planar-imaging (SE-EPI) MRE only requires a single breath-hold. In this study we compared 2D SE-EPI and 2D rapid-GRE MRE sequences at 3T in healthy children and children with suspected fibrosis. Both SE-EPI and rapid-GRE had good repeatability, reproducibility, inter-reader agreement, and quantitative agreement in liver stiffness. SE-EPI provided larger measurable liver ROI sizes than rapid-GRE. SE-EPI may be desirable for measuring fibrosis in children with limited or inconsistent breath-hold ability and reduce scan times.

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Gadoxetic acid-enhanced perfusion quantification in the liver and spleen in portal hypertension
Stefanie Hectors1,2, Octavia Bane1,2, Paul Kennedy1,2, Scott Friedman3, Thomas Schiano3, Maria Isabel Fiel4, Swan Thung4, Aaron Fischman5, and Bachir Taouli1,2

1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 4Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 5Department of Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States

The goal of our study was to assess the potential value of perfusion quantification using DCE-MRI with gadoxetic acid in the liver and spleen for noninvasive assessment of portal hypertension (PH). We found that the liver uptake fraction was significantly negatively correlated with hepatic venous pressure gradient measurements. We conclude that liver perfusion quantification is promising for noninvasive assessment of PH. After validation of these findings in a larger cohort of patients, DCE-MRI may potentially decrease the need of invasive portal pressure measurements.

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Alteration of blood flow in hepatic fibrosis: preliminary results
JeongHee Yoon1, Jeong Min Lee1,2, Moon Jung Hwang3, Hiroyuki Kabasawa4, and Joon Koo Han1

1Seoul National University Hospital, Seoul, Korea, Republic of, 2Seoul National University college of medicine, Seoul, Korea, Republic of, 3GE Healthcare, Seoul, Korea, Republic of, 4GE Healthcare, Tokyo, Japan

Portal flow is believed to relate to liver regeneration and may reflect the hemodynamic change of liver cirrhosis. So far, it has been relied on Doppler examination, which only sampled in local two-dimensional (2D) acquisition planes. Recently, four-dimensional (4D) flow acquisition of MRI may provide more accurate vascular flow information. However, there have been only a few studies of the liver in the literature.

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A Promising Procedure for the Staging of Liver Fibrosis Using Hepatocyte Fraction
Weibo Chen1, Tian Qiu2, Eunju Kim3, and YuXin Shi*2

1Philips Healthcare, Shanghai, China, 2Shanghai Public Health Clinical Center Affiliated to Fudan University, Shanghai, China, 3Philips Healthcare, Seoul, Korea, Republic of

Liver biopsy is an invasive and painful procedure for staging liver fibrosis. This study aimed to evaluate a new procedure by injecting a hepatobiliary-specific contrast agent Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) and using a pharmacokinetic model to stage the liver fibrosis noninvasively. The hepatocyte fraction extracted from this new model decreased as the liver fibrosis stage increased, indicating that it might be a promising biomarker for the noninvasive staging of liver fibrosis.

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Non-invasive assessment of portal hypertension using magnetic resonance elastography and ultrasound shear wave elastography of the liver and spleen.
Paul Kennedy1,2, Octavia Bane1,2, Stefanie Hectors1,2, Scott Friedman3, Thomas Schiano3, Maria Isabel Fiel4, Swan Thung4, Aaron Fischman5, and Bachir Taouli1,2

1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 4Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 5Department of Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States

The aim of this ongoing prospective study is to investigate the utility of both 2D and 3D MR elastography (MRE) and ultrasound shear wave elastography (SWE) for the assessment of portal hypertension in patients with chronic liver disease. Initial results indicate that 3D MRE measured spleen stiffness and the spleen to liver stiffness ratio measured with 3D MRE and SWE significantly correlate with hepatic venous pressure gradient measurement. This suggests that 3D MRE is sensitive to physiological changes associated with portal hypertension. Confirmation in a larger patient cohort may validate 3D MRE as a non-invasive surrogate for portal pressure measurement.

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Assessment of chronic hepatitis B liver fibrosis staging using Intravoxel incoherent motion MRI compared with ultrasonic transient elastography
Qing Li1, Shuangshuang Xie1, Zhizheng Zhuo2, and Wen Shen1

1Tianjin First Center Hospital, Tianjin, China, 2Philips healthcare, Beijing China, Beijing, China

we compare the value of IVIM and ultrasonic transient elastography in evaluating the fibrosis staging of patients with chronic hepatitis B, and we found that IVIM is potential to assese chronic hepatitis B liver fibrosis and inferior to ultrasonic transient elastography, however Dslow and f have comparable diagnostic value with ultrasonic transient elastography in evaluating in liver fibrosis stage≥F3.

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New MRI Method for the Detection of Liver Fibrosis: Validation and Staging
Jie Zheng1, Lichuan Yang2, Joseph Gabriel2, Guangzhong Wang2, Shaozhu Liu2, Tony Wang2, and Bob Zhang2

1Radiology, Washington University in St. Louis, Saint Louis, MO, United States, 2Kunming Biomed International, Kunming, China

The purpose of this study was to develop a MR imaging markers for quantitative assessment of liver fibrosis and validate the method. Both normal monkeys and monkeys with non-alcoholic steatohepatitis were used for the validation study compared to histopathology of liver biopsy specimens. Liver extracellular volume was quantified and correlated strongly with biopsy fibrosis scores.

 


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Liver injury monitoring, fibrosis staging and inflammatory grading with T1rho MR imaging: an experimental study in rats with carbon tetrachloride intoxication
shuangshuang xie1, Qing Li1, hanxiong qi1, Kun Zhang1, zhizheng zhuo2, Yue Cheng1, and Wen Shen1

1Tianjin First Center Hospital, Tianjin, China, 2Clinical Science, Philips Healthcare, Beijing, China

In this article, we investigate the value of T1rho MRI in monitoring CCl4-induced liver injury, staging liver fibrosis and grading inflammation activity in a rat model. Forty-one model rats underwent black blood T1rho MRI in multiple time points, and eleven normal rats selected as control group. Liver T1rho values were measured in different time points and compared between different fibrosis stages and inflammation grades. Our result showed that T1rho MRI can be used to monitor CCl4-induced liver injury. Changes of liver T1rho values were the result of a combination of liver fibrosis and inflammation activity, and inflammation activity had a greater impact on liver T1rho values than fibrosis.

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Staging liver fibrosis with T1rho MR imaging and ultrasonic elastography alone and in combination in patients with chronic hepatitis B
shuangshuang xie1, Qing Li1, hanxiong qi1, Kun Zhang1, zhizheng zhuo2, Yue Cheng1, and Wen Shen1

1Tianjin First Center Hospital, Tianjin, China, 2Clinical Science, Philips Healthcare, Beijing, China

In this article, we compare the diagnostic efficiency of T1rho, ultrasonic elastography (UE) and the combination of them in staging liver fibrosis. Thirty-two patients with chronic hepatitis B underwent T1rho MRI and UE were analyzed. T1rho is better than UE in staging liver fibrosis, and the combination of T1ho and UE can improve the diagnostic efficiency in differentiating F1 from F2-4.

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Non-invasive assessment of hepatic fibrosis and inflammatory activity in patients with chronic hepatitis B:Comparison of multiple diffusion-weighted MR imaging models
Fang fang Fu1, Xiaodong Li1, Yan Bai1, Qiuyu Liu2, Da peng Shi1, Yusong Lin3, and Meiyun Wang1

1Department of Radiology, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Zhengzhou, China, 2Department of Pathology, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University,Zhengzhou, 450003, China., Zhengzhou, China, 3Cooperative Innovation Center of Internet Healthcare & School of Software and Applied Technology, Zhengzhou University, Zhengzhou, 450001, China., Zhengzhou, China

In this study, we assessed the value of various diffusion parameters obtained from monoexponential, biexponential, and stretched-exponential DWI models in predicting the hepatic fibrosis (HF) stage and inflammatory activity grade in patients with chronic hepatitis B (CHB). We found that true diffusion coefficient (Dt) and distributed diffusion coefficient (DDC) are promising indicators and outperform the standard apparent diffusion coefficient (ADCst) for HF staging and inflammatory activity grading. We believe that biexponential and stretched-exponential model could be more helpful compared with monoexponential model in monitoring the progression of HF and inflammatory activity, guiding therapy, and assessing the effect of the treatment.


Liver Fat, Iron, Perfusion & Function

Exhibition Hall
Monday 13:45 - 14:45
 Body: Breast, Chest, Abdomen, Pelvis

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Correlation between susceptibility, R2* and PDFF in liver
Ramin Jafari1,2, Adrija Mamidipalli3, Walter Henderson3, Gavin Hamilton3, Pascal Spencemille2, and Mark Bydder4

1Meinig School of Biomedical Engineering, Cornell University, New York, NY, United States, 2Department of Radiology, Weill Medical College of Cornell University, New York, NY, United States, 3Radiology, UCSD, San Diego, CA, United States, 4Radiological Sciences, UCLA, Los Angeles, CA, United States

A susceptibility difference between the water and fat components in liver should give rise to a linear increase in R2* with proton density fat fraction (PDFF). This is observed empirically although the value of the susceptibility difference is subject to variability (from ~0 ppm to 0.75ppm). The present abstract aims to measure the susceptibility difference directly by measuring liver susceptibility as a function of the PDFF in patients with fatty liver.

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Quantitative DCE-MRI Analysis without an Arterial Input Function: A Comparison Study with Compartment Modeling in Liver Lesions
Ramin Jafari1, Pascal Spincemaille2, Martin R. Prince2, Liangdong Zhou1, and Yi Wang1

1Cornell University, New York, NY, United States, 2Weill Cornell Medicine, New York, NY, United States

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a noninvasive techniques to study dynamics of enhancement curves after administration of contrast agent. The traditional Kety’s based compartment modeling requires an arterial input function (AIF) to estimate perfusion parameters. Estimated perfusion parameters are highly dependent on the selected AIF including its magnitude and shape. We propose Quantitative transport mapping (QTM) which doesn’t require an AIF and incorporates both temporal and spatial dynamics of the contrast agent for similar analysis.

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Temperature sensitivities of T1, fat fraction and water resonance frequency characterised in ex vivo human livers
Liam AJ Young1, Carlo DL Ceresa2, Ferenc E Mozes1, Jane Ellis1, Ladislav Valkovic3,4, Constantin C Coussios5, Peter J Friend2, and Christopher T Rodgers1,6

1Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom, 2Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom, 3University of Oxford, Oxford, United Kingdom, 4Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia, 5Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom, 6Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom

MR techniques enable viability assessment of ex vivo organs for transplantation and non-invasive post-mortem examinations. However, temperature variations in ex vivo tissue and cadavers can drastically alter MR measurements of T1 and fat fraction, which risks masking underlying pathology if not considered carefully. Therefore, we investigated the changes observed in fat fraction and T1 in ex vivo human livers during a period of cooling and re-warming. Obtaining multiple measurements at different temperatures enabled determination of temperature sensitivity independent of underlying pathology, which could be used to perform a “temperature correction” of ex vivo data allowing greater sensitivity to pathological changes. 

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Accuracy of multi-echo Dixon sequence in the quantification of hepatic steatosis in Chinese children and adolescents, with reference to HISTO
Yuzhen Zhao1, Jianli Zhou1, Jiaqi Liu1, Shaoming Zhou1, Yungen Gan1, Weiguo Cao1, and Mengzhu Wang2

1Shenzhen children’s hospital, Shenzhen, China, 2Siemens Healthcare, Guangzhou, China

This study investigated the accuracy of MRI in quantifying liver fat of 86 Chinese children and adolescents, with magnetic resonance spectroscopy (MRS) as reference. MRI and MRS were performed with multi-echo Dixon (ME Dixon) and HISTO sequence respectively to calculate hepatic proton density fat fraction (PDFF). Hepatic steatosis was diagnosed using MRS-PDFF > 5% as threshold. Spearman analysis indicated excellent correlation between ME Dixon and MRS (r>0.9,P<0.01). Bland-Altman analysis demonstrated good agreement between these two methods, indicating that ME Dixon can be an accurate way to detect hepatic steatosis in children and adolescents.

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Liver proton density fat fraction as a trial endpoint in an international multi-site phase-II trial in patients with type 2 diabetes mellitus following treatment with duodenal mucosal resurfacing
Naomi S Sakai1, Alan Bainbridge2, David Maggs3, Margaret Hall-Craggs1, Rachel Batterham4,5, Stuart Taylor1, and Manil Chouhan1

1UCL Centre for Medical Imaging, University College London, London, United Kingdom, 2Department of Medical Physics, University College London Hospitals, London, United Kingdom, 3Fractyl Laboratories Inc., Lexington, MA, United States, 4Centre for Obesity Research, University College London, London, United Kingdom, 5National Institute of Health Research, UCLH Biomedical Research Centre, London, United Kingdom

Vendor-certified proton density fat fraction (PDFF) sequences are commercially available across multiple scanner systems and represent a robust method for quantification of liver fat and liver T2* mapping. Type 2 diabetes mellitus (T2DM) is associated with non-alcoholic fatty liver disease and dysregulation of iron homeostasis. Duodenal mucosal resurfacing (DMR) is a novel treatment for patients with T2DM who have poor glycaemic control. We describe our technique for quality assurance across multiple sites using custom fat-water phantoms and report preliminary liver PDFF and liver iron concentration results from a cross-site, multi-vendor study in patients at baseline and 12 weeks after DMR.

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A new calibration between R2* and Liver Iron Concentration derived from 167 clinical cases
Gregory Colin Brown1,2, Gary J Cowin1, and Graham J Galloway1,3

1Centre for Advanced Imaging, University of Queensland, St Lucia, Qld., Australia, 2School of Health Sciences, University of South Australia, Adelaide, SA, Australia, 3Translational Research Institute, Woolangabba Qld., Australia

The commonly used equation to determine Liver iron concentration (LIC) from R2* was developed from a very small cohort (n=23) and an acquisition approach significantly different to that currently used in clinic. Three subsequent calibrations used progressively larger moderate (n=43-88) to derive divergent results. This study measured liver R2* from 835 gradient echo relaxometry acquisitions in 167 clinical examinations. Correlation between R2* and reference LIC measurement was evaluated for first to third order polynomials. A linear equation provided the best fit, delivering a new calibration equation that differs significantly from earlier work.

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IRON MEASUREMENTS BY QUANTITATIVE MRI-R2* AT 3.0 AND 1.5 T IN COMPARISON TO SQUID BIOMAGNETIC LIVER SUSCEPTOMETRY (BLS)
Jin Yamamura1, Björn Schönnagel1, Sarah Keller2, Christoph Berliner1, Enver Tahir1, Regine Grosse3, Zhiyue Jerry Wang4, Gerhard Adam1, and Roland Fischer1,5

1Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Radiology, Charité University Medicine, Berlin, Germany, 3Haemato-Oncology, University Medical Center Hamburg, Hamburg, Germany, 4University of Texas Southwestern Medical Center, Dallas, TX, United States, 5UCSF Benioff Children's Hospital Oakland, Oakland, CA, United States

In this study the suitability of a 3.0 T imager for iron measurements over the whole range of possible iron concentrations in the liver and other organs or glands is investigated. For this purpose the results on liver iron is compared for the feasibility of 3.0T to both 1.5T MRI and SQUID BLS.

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Correlation Between Somatostatin Treatment and Elevated Hepatic Fat Fraction on MRI in Patients with Neuroendocrine Tumors
Preeti Arun Sukerkar1, Kathleen Hornbacker2, Jarrett Rosenberg1, Pamela Kunz2, and Pejman Ghanouni1

1Radiology, Stanford University, Stanford, CA, United States, 2Oncology, Stanford University, Stanford, CA, United States

Up to 90% of neuroendocrine tumor patients have metastatic disease in the liver at diagnosis. These patients are treated with somatostatin analog therapy and monitored with CT or MRI. We demonstrate in a retrospective study that somatostatin therapy is associated with the development of elevated liver fat fraction on MRI. Furthermore, preliminary results suggest that hepatic steatosis decreases lesion detectability on CT compared to MRI. Studies are ongoing to determine the severity of steatosis and relationship to cumulative somatostatin dose, variation in fat fraction over time and the response to change in medication, and effect on liver function.

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MRI Relaxometry in a Rat Model of Nonalcoholic Steatohepatitis (NASH)
Iris Y. Zhou1, Nicholas Rotile1, Veronica Clavijo Jordan1, Gunisha Arora2, Smitha Krishnan2, Hannah Slattery1, Noah Warner1, Christian T. Farrar1, Bryan C. Fuchs2, and Peter Caravan1

1Athinoula A. Martinos Center for Biomedical Imaging, Institute for Innovation in Imaging (i3), Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, 2Division of Surgical Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States

Nonalcoholic steatohepatitis (NASH), characterized by the presence of steatosis, inflammation and fibrosis, has a high prevalence and is associated with poor outcomes. While liver biopsy is the gold standard for assessment of fibrosis, it is invasive with potential complications. Recently, liver T1 measurement without intravenous contrast has been proposed to stage liver fibrosis. Here, we evaluated T1 mapping for monitoring disease progression and treatment response in a choline-deficient high-fat diet rat model of NASH. Instead of correlating with fibrosis, we found a strong correlation of T1 with histologically determined liver fat fraction but not with histological and biochemical measures of fibrosis. 

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Relation between T1 and T2 of liver water and fat and Proton Density Fat Fraction estimated by a flip angle corrected multi-TR, multi-TE single breath-hold 1H MRS STEAM sequence
Gavin Hamilton1, Alexandra N Schlein1, Michael S Middleton1, Rohit Loomba2, and Claude B Sirlin1

1Liver Imaging Group, Department of Radiology, University of California San Diego, La Jolla, CA, United States, 2NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, CA, United States

We examine the relationship between liver water and fat T1 and T2, and PDFF in adult subjects undergoing non-contrast exams using a version of the multi-TR, multi-TE 1H MRS sequence that estimates and corrects for flip angle based on a non-steady-state approach.

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MRI Relaxometry based Liver Iron Content Determination: Comparing Gradient-Echo R2* and Spin-Echo with respect to Age and Gender
Arthur Peter Wunderlich1,2, Valeria Mauro1, Meinrad Beer1, Stefan Andreas Schmidt1, and Holger Cario3

1Dept. for Diagnostic and Interventional Radiology, Ulm University, Medical Center, Ulm, Germany, 2Section for Experimental Radiology, Ulm University, Medical Center, Ulm, Germany, 3Clinic for Pediatric and Adolescent Medicine, Ulm University, Medical Center, Ulm, Germany

To address probable differences in signal characteristics between spin-echo (SE) and gradient-echo (GRE), 83 patients suspected for liver iron overload were investigated with 1.5 T MRI with the approved Ferriscan® method based on SE, and a prototype breathhold 3D GRE protocol employing parallel imaging with in-line R2* calculation. R2* values were correlated with reference LIC for all patients together and in subgroups according to age and gender. Highly significant differences (P=0.009) were found between males and females in the age range from 12 to 45 years, possibly reflecting different underlying iron storage mechanisms.

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Susceptibility-weighted imaging (SWI) compared to T2* mapping in the presence of hepatic steatosis and fibrosis
Verena Carola Obmann1, Nando Mertineit1, Annalisa Berzigotti2, Christina Marx1, Lukas Ebner1, Michael Ith1, Johannes Heverhagen1, Andreas Christe1, and Adrian Huber1

1Diagnostic, Interventional and Pediatric Radiology, Inselspital, Bern, Switzerland, 2Visceral Surgery and Medicine, Inselspital, Bern, Switzerland

We hypothesized, that susceptibility weighted imaging (SWI) and T2*-mapping are dependent on liver steatosis, which should be taken into account when using these parameters to grade liver fibrosis and cirrhosis. In this study 184 patients underwent multiparametric MRI at 3T including SWI, T1/T2* mapping as well as proton density fat fraction quantification and MR elastography as reference standard. SWI and T2* were both highly dependent on the degree of liver steatosis (p<0.001). However, SWI allowed a better differentiation between liver fibrosis grades (p <0.001) than T2*. Nevertheless, both parameters are useful predictors for liver fibrosis when using a multiparametric approach.

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Quantitative evaluation of hepatic steatosis using rapid multi-echo Dixon technique in patients with obesity
Wei Wei1,2, Yan Bai1,2, Yusong Lin3,4, and Meiyun Wang1,2

1Department of Radiology, Henan Provincial People’s Hospital, Zhengzhou,Henan, China, 2Henan Key Laboratory for Medical Imaging of Neurological Diseases, Zhengzhou,Henan, China, 3Cooperative Innovation Center of Internet Healthcare,Zhengzhou University, Zhengzhou,Henan, China, 4School of Software and Applied Technology, Zhengzhou University, Zhengzhou,Henan, China

This study aimed to demonstrate the feasibility and accuracy of magnetic resonance imaging multi-echo Dixon rapid liver fat quantitative analysis for liver fat content in the obese patients. In the first of our study, we performed liver scan on 17 obese patients using multi-echo Dixon rapid liver fat quantification technique and then we re-measured the entire liver fat content by previous method manually drawing ROIs on each liver segment. The Bland-Altman plots and Pearson correlation analysis were performed on the quantitative results of the above two methods. There statistical analysis showed there were good consistence and highly correlated with the two methods. We found the multi-echo Dixon rapid liver fat quantitative can simply, feasibility and accurately assess the liver fat content in the patients with obese .

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Determining Liver Function: Comparison of Gadoxetate Pharmacokinetic Models Using Perfusion Imaging
Markus Karlsson1, Susmita Basak2, David Longbotham2, Steven Sourbron2, Gunnar Cedersund3, and Peter Lundberg1

1Department of Medical and Health Sciences, Linköping University, Linköping, Sweden, 2Imaging Biomarkers group, Department of Biomedical Imaging, Leeds University, Leeds, United Kingdom, 3Department of Biomedical Engineering, Linköping University, Linköping, Sweden

Hepatic uptake rate of Gadoxetate is a liver function biomarker. Different approaches for pharmacokinetic modelling exists, both with regards to model architecture and choice of input data, with both blood and spleen being used to estimate input‑function. We fitted three models to perfusion data, using both aorta and portal venous inputs, as well as splenic input. We showed that the hepatic uptake rate of Gadoxetate is robust, in that the uptake rate is not very dependent on how the liver perfusion is modelled. However, the choice of vascular or splenic input can affect the uptake rate.

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Phase-contrast MRI-based estimation of labeling efficiency for liver pseudo-Continuous Arterial Spin Labeling
Magdalena Sokolska1, Lucy Caselton2, Stuart Taylor3, and Manil Chouhan3

1Medical Physics and Biomedical Engeneering, University Collenge London Hospitals, London, United Kingdom, 2Imaging, University College London Hospitals, London, United Kingdom, 3Centre for Medical Imaging, University College London, London, United Kingdom

Chronic liver disease is associated with profound changes in the dual portal venous (PV) and hepaticarterial (HA) blood supply to the liver. Pseudo-continuous arterial spin labeling (pCASL) canmeasure hepatic blood non-invasively and separate PV and HA contributions, however quantification is directly proportional to the labeling efficiency (alpha), and can therefore significantly affect overall quantification. This study estimates alpha for the PV, descending aorta (DA) and HA using a Bloch equation simulator and velocities measured directly using phase-contrast MRI at the level of the labeling plane, taking into account the effects of labeling plane angulation. We demonstrate that it is reasonable to assume a labeling efficiency of 0.85 for hepatic pCASL in normal volunteers.

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Validation of T1 map on Gd-EOB-DTPA-enhanced liver MRI as a quantitative biomarker of liver function: Calibration, reproducibility, and diagnostic value
Jimi Huh1, Gyeongmin Park2, Tae Young Lee2, Jisuk Park1, Bohyun Kim1, Hye Jin Kim1, Jei Hee Lee1, Jai Keun Kim1, and Kyung Won Kim3

1Radiology, Ajou university hospital, Suwon, Korea, Republic of, 2Ulsan University Hospital, Ulsan, Korea, Republic of, 3Radiology, Asan Medical Center, Seoul, Korea, Republic of

T1 map using MOLLI sequence on EOB-MRI showed promise for evaluating liver function in patients with liver cirrhosis. Especially, T1-map was accurate to evaluate T1 values based on quantitative phantom study and accurate to diagnose decompensated liver cirrhosis. However, test-retest reproducibility was moderate, requiring further technical improvement.

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Quantitative Measurement of Serial Contrast Agent Distribution between Liver and Blood in Patients with Chronic Liver Disease using T1 mapping
Puneet Sharma1

1Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States

This study investigates the post-contrast time sensitivity of liver-to-blood partition coefficient. In vivo change in liver-to-blood contrast distribution was calculated at 3 time-points following contrast administration using a fast inversion-recovery Look-Locker T1 mapping approach. While measurement and exam time variation did not reveal a consistent equilibrium time threshold, results show that contrast distribution becomes increasingly different between chronic and non-chronic liver disease groups at least 5 minutes post-contrast, allowing possible measurement of liver extracellular volume fraction.

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Noninvasive Assessment of Abdominal Adipose Tissues and Fat Quantification of the Liver and Pancreas in Type 2 Diabetes Mellitus
Manoj Kumar Sarma1, Andres Saucedo1, Daniel Kohanghadosh1, Edward Xu1, Ely R. Felker1, Christine H. Darwin2, and M. Albert Thomas1

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

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder effecting millions of people worldwide. T2DM is associated with insulin resistance and adipose tissue dysfunction which promote ectopic fat deposition and lipotoxicity in muscle, liver, and pancreatic beta cells. However, the impact of dysfunctional adipose tissue has not been fully elucidated. Here we examined the adipose tissue (SAT), visceral adipose tissue (VAT), hepatic fat fraction (HFF) and pancreatic fat fraction (PFF) difference between T2DM and age-matched healthy controls using the 6-point Dixon MRI technique and assess relationship with  biochemical markers of insulin resistance. We observed trend of increasing VAT, SAT and TAT volume in T2DM patients along with significantly higher HFF% and PFF%. HbA1c in T2DM patients were positively correlated with VAT, total adipose tissue and HFF%. Our preliminary results of increased SAT and VAT reaffirmed that central obesity is connected with the evolution of T2DM. Increased HFF% and correlation of increased HbA1c with increased HFF% in T2DM suggested that T2DM patients suffer from nonalcoholic fatty liver disease. In summary, increased liver, pancreatic fat, and adipose tissue characterize T2DM patients and the insulin resistance. Better understanding of these results will help us in formulate early intervention strategies and to evaluate the efficacy of therapies.

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3D Stack-of-Stars Radial Imaging for Motion-Robust Free-Breathing Hepatobiliary Phase Imaging
Matthias R Muehler1, Ty A Cashen2, Kang Wang2, Ali Ersoz3, Ersin Bayram4, and Scott B Reeder1,5,6,7

1Departments of Radiology, University of Wisconsin, Madison, WI, United States, 2Global MR Applications and Workflow, GE Healthcare, Madison, WI, United States, 3Global MR Applications and Workflow, GE Healthcare, Waukesha, WI, United States, 4Global MR Applications and Workflow, GE Healthcare, Houston, TX, United States, 5Biomedical Engineering, University of Wisconsin, Madison, WI, United States, 6Medical Physics, University of Wisconsin, Madison, WI, United States, 7Medicine and Emergency Medicine, University of Wisconsin, Madison, WI, United States

Free-breathing hepatobiliary phase imaging with gadoxetate disodium is challenging due to respiratory motion. This study examines an intrinsically motion-robust fat-suppressed T1-weighted 3D stack-of-stars gradient echo technique (LAVA Star) with soft gating. An estimate of respiratory motion is derived either from a navigator tracker with a wide acceptance window, which produces the best image quality, or self-navigation, which offers the most convenient workflow, particularly in challenging clinical situations. In either case, the retrospective soft gating reduces scan time variability compared to a conventional prospective navigator.

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Inter-site repeatability and quantitative assessment of hepatic transporter function with DCE-MRI in rats
Claudia Green1, Sirisha Tadimalla2, Denise Steinmann3, Steven Sourbron2, Sascha Koehler4, Hans-Paul Juretschke3, Iina Laitinen3, John C. Waterton5,6, Paul D. Hockings7,8, Catherine D. G. Hines9, and Gunnar Schuetz1

1MR & CT Contrast Media Research, Bayer AG, Berlin, Germany, 2Leeds Imaging Biomarkers Group, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, United Kingdom, 3R&D TIM - Bioimaging Germany, Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany, 4Bruker BioSpin MRI GmbH, Ettlingen, Germany, 5Manchester Science Park, Bioxydyn Ltd, Manchester, United Kingdom, 6Division of Informatics Imaging & Data Sciences, School of Health Sciences, Faculty of Biology Medicine & Health, Centre for Imaging Sciences, Manchester, United Kingdom, 7BioVenture Hub, Antaros Medical, Mölndal, Sweden, 8Chalmers University of Technology, MedTech West, Gothenburg, Sweden, 9Merck & Co., Inc., West Point, PA, United States

Drug-induced liver injury can halt liver-metabolized drug development or cause withdrawal from the market. Toxicologists lack appropriate and reproducible assays. We present repeatability and reproducibility results from a multi-center study with dynamic gadoxetate-enhanced MR imaging biomarkers of hepatic transporter-mediated injury in rats. Our study supports the development of a validated liver function-specific quantitative MR imaging biomarker, and we demonstrate that the biomarkers are repeatable and that the previously reported MR assay findings are reproducible across three centers.

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Preoperative Remnant Liver Function Evaluated by a Clinical-Available Gd-EOB-DTPA-Enhanced MR Imaging Protocol: Independently Significant Indicator in Predicting Posthepatectomy Liver Failure in HCC Patients
Yajie Wang1, Lin Zhang2,3, Jia Ning1, Xinjing Zhang3, Xuedong Wang3, Shizhong Yang3, Jiahong Dong3, and Huijun Chen1

1Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, 2Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, China, 3Beijing Tsinghua Changgung Hospital, School of Medicine, Tsinghua University, Beijing, China

Preoperative remnant liver function evaluation is important for surgery planning and reducing posthepatectomy liver failure (PHLF) rate in hepatocellular carcinoma (HCC) patients. This study demonstrated that the remnant liver functions preoperatively evaluated by a clinical available Gd-EOB-DTPA-enhanced imaging protocol were the independently significant indicator in predicting PHLF after adjusting for other PHLF risk factors including sex, age, hepatitis, cirrhosis, preoperative blood serum indices, operation time, intraoperative blood loss and intraoperative blood transfusion in the multivariate logistic regression.

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Clinical, technical, and biochemical predictors of adequate hepatobiliary phase enhancement on Gadobenate-Dimeglumine-enhanced MRI of the liver in patients with chronic liver disease and HCC
Jingbiao Chen1, Sichi Kuang1, Yao Zhang1, Hao Yang1, Ying Deng1, Bingjun He1, Kathryn Fowler2, Claude B. Sirlin2, and Jin Wang1

1Department of Radiology, The third affiliated hospital of Sun Yat-sen University, guangzhou, China, 2Department of Radiology, University of California at San Diego, La Jolla, CA, United States

Liver dysfunction impairs the uptake of gadobenate dimeglumine by liver parenchyma, which reduces hepatocellular carcinoma (HCC) conspicuity on hepatobiliary phase (HBP) images. Although the effect of Child-Pugh class and some biologic factors have been investigated, there is a paucity of data on other plausible predictors of HBP adequacy. Here we show that elevated albumin level, prolonged HBP delay time, and absence of liver cirrhosis predict HBP adequacy on gadobenate-MRI in patients with chronic liver disease and HCC. In the subset of patients with cirrhosis and HCC, adequate HBP was associated with elevated serum creatinine level and prolonged HBP delay time.

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Bayesian selection of dedicated liver iron quantification MRI for patients with clinically-significant iron overload
Takeshi Yokoo1, Ivan Pedrosa1, Diego Hernando2, and Scott B Reeder2

1UT Southwestern Medical Center, Dallas, TX, United States, 2University of Wisconsin at Madison, Madison, WI, United States

R2- and R2*-MRI has become an important clinical tool to noninvasively quantify liver iron concentration (LIC) in patients with significant iron overload who may require iron-reducing therapy. However, these highly specialized exams can only be performed on dedicated 1.5T scanners meeting certain technical specifications. Therefore, a priori selection of patients according to their pre-test probabilities of significant iron overload may help correctly match the patients’ clinical needs to the appropriate MRI scanner and exam protocol. This study derives a Bayesian patient selection criterion based on serum ferritin to identify patients who may and may not benefit from dedicated liver iron quantification MRI.

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A Quantitative MRI Phantom to Mimic the Simultaneous Presence of Fat, Iron, and Fibrosis
Ruiyang Zhao1,2, Gavin Hamilton3, Jean H. Brittain1,4, Scott B. Reeder1,2,4,5,6,7, and Diego Hernando1,2,4

1Radiology, University of Wisconsin-Madison, Madison, WI, United States, 2Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, 3Radiology, University of California, San Diego, San Diego, CA, United States, 4Calimetrix LLC, Madison, WI, United States, 5Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States, 6Emergency Medicine, University of Wisconsin-Madison, Madison, WI, United States, 7Medicine, University of Wisconsin-Madison, Madison, WI, United States

Fat, iron and fibrosis are important features of liver disease that commonly coexist. Emerging quantitative MRI biomarkers including proton density fat fraction (PDFF), R2*/R2 and T1 enable quantification of fat, iron, and fibrosis, respectively, and require quantitative MR phantoms for validation and quality assurance. Although current phantoms enable separate adjustment of PDFF, R2*/R2 or T1, there is an unmet need for phantoms that accurately mimic MRI signals in the presence of simultaneous fat, iron and fibrosis by jointly controlling PDFF, R2*/R2 and T1. In this work, we develop and validate a novel phantom that jointly controls PDFF, R2*/R2 and T1.


What Are We, Chopped Liver?

Exhibition Hall
Monday 14:45 - 15:45
 Body: Breast, Chest, Abdomen, Pelvis

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B0 and B1 Inhomogeneities in the Liver at 1.5T and 3.0T
Nathan Tibbitts Roberts1,2, Diego Hernando1,3, Timothy J Colgan1, Louis A Hinshaw1, Dylan M Kernan1, and Scott B Reeder1,3,4,5,6

1Radiology, University of Wisconsin - Madison, Madison, WI, United States, 2Electrical and Computer Engineering, University of Wisconsin - Madison, Madison, WI, United States, 3Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, 4Medicine, University of Wisconsin - Madison, Madison, WI, United States, 5Emergency Medicine, University of Wisconsin - Madison, Madison, WI, United States, 6Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States

Inhomogeneities in the static (B0) and transmitted (B1) magnetic fields can lead to artifacts and image degradation for a large variety of imaging applications. Quantitative MRI applications that fail to account for B0 and B1 inhomogeneities may suffer from substantial errors. Understanding the range of expected B0 and B1 inhomogeneities experienced in vivo is essential to engineer solutions aimed at avoiding or correcting for these effects. In this work, we measure the B0 and B1 inhomogeneities in the liver of 60 and 312 patients, respectively, at both 1.5T and 3.0T.

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Quantitative Assessment of Liver Function using Hepatocyte Fraction on Gd-EOB-DTPA-Enhanced MRI
Xueqin ZHANG1, Jian LU1, Jifeng JIANG1, Ding DING1, and Weibo CHEN2

1the Third People’s Hospital of Nantong, Nantong, China, 2Philips Healthcare, Shanghai, China

The purpose of this study was to investigate the ability of hepatocyte fraction on Gd-EOB-DTPA-enhanced MRI for the assessment of liver function of HBV-induced cirrhosis. We used Look-Locker sequences to acquire T1 mapping images pre and post-contrast at 20 minutes after Gd-EOB-DTPA administration, hepatocyte fraction (HeF) and KHep values were measured. Our study showed that hepatocyte fraction is useful for the evaluation of liver function of HBV-induced cirrhosis.

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Color-Encoded Multiparametric 3D Fast Dixon
Kenneth L Weiss1, Judd M Storrs2, and Manohar S Roda2

1Radiology, University of Miami Miller School of Medicine, Miami, FL, United States, 2Radiology, University of Mississippi Medical Center, Jackson, MS, United States

We developed a novel color-encoding technique for Dixon imaging that combines in-phase, out-of-phase and water images into a single intuitive color image. We demonstrate its potential to facilitate interpretation of these complex information-rich datasets, reduce the number of requisite images to be stored and reviewed, and thereby extend Dixon’s clinical utility across the body.

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Stretched exponential diffusion-weighted imaging model in quantitative diagnosis of nonalcoholic fatty liver disease : a rabbit model study
Chang li1,2, Xianfu luo2, Weiqiang Dou3, Yun Peng1, Jingtao wu2, and Jing Ye2

1XiangYa school of medicine, Central South University, Changsha, China, 2Clinical Medical School of Yangzhou University, Northern Jiangsu People’s Hospital, Yangzhou, China, 3GE Healthcare,MR Research China, beijing, China

We aimed to investigate if a stretched exponential diffusion weighted imaging model (SEM) can be applied to assess nonalcoholic liver disease (NAFLD) disease by providing distributed-diffusion-coefficient (DDC) and α separately evaluating mean intravoxel diffusion rate and diffusion heterogeneity. The SEM model was then applied to analyze NAFLD in a rabbit model and compared with a mono-exponential (ME) model. While DDC from the SEM model showed comparable values with apparent-diffusion-coefficient (ADC) estimated in the ME model, alpha indicated more robust performance in the diagnosis of nonalcoholic steatohepatitis (NASH). Therefore, SEM model showed a great potential in early diagnosis of NASH.

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Super high temporal frame rate reconstruction in abdominal dynamic contrast-enhanced MRI using stack-of-stars acquisition (LAVA-Star) under free breathing toward comprehensive hemodynamic analysis of the abdominal vessels and organs: a feasibility study
Tetsuya Wakayama1, Daiki Tamada2, Kang Wang3, Ty Cashen3, Ali Ersoz4, Shintaro Ichikawa2, Hiroshi Onishi2, and Utaroh Motosugi2

1MR Collaboration and Development, GE Healthcare, Hino, Japan, 2Radiology, University of Yamanashi, Chuo, Japan, 3MR Collaboration and Developement, GE Healthcare, Madison, WI, United States, 4MR Engineering, GE Healthcare, Waukesha, WI, United States

We demonstrated the feasibility of breath hold-free dynamic MRI of the liver using stack-of-stars acquisition with super high temporal frame rate (0.5s/phase) reconstruction.  Stack-of-stars acquisition with soft gating technique enabled to acquire sufficient quality of dynamic MRI without breath-holdings. The super high frame rate reconstruction provided the better time-intensity curves, which enabled to capture accurate time-to-peak enhancement of each vessel, a second bolus pass in the aorta, and the peak delay from splenic vein to main portal vein. This technique is feasible for the comprehensive understandings of hemodynamics in arterial and portal venous circulation and abdominal organs.

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Better Depiction of Cystic Duct with Breath-hold 3D MRCP accelerated with GRASE as compared with FSE-based MRCP with Compressed Sensing at 1.5T
Mamoru Takahashi1, Yasuo Takehara2, Norihiro Tooyama1, Katsutoshi Ichijo1, Yasutomo Katsumata3, Akira Suwa3, and Harumi Sakahara4

1Seirei Mikatahara General Hospital, Hamamatsu, Japan, 2Nagoya University, Graduate School of Medicine, Nagoya, Japan, 3Philips Japan, Ltd, Tokyo, Japan, 4Hamamatsu Univ. Hospital, Hamamatsu, Japan

We compared the depiction of the cystic duct between two types of 3D breath-holding MRCP accelerated with GRASE (GRASE-MRCP) and FSE with compressed sensing (CS-MRCP) at 1.5T. Although imaging time and overall image quality was the same, breath-hold MRCP accelerated with GRASE allowed better depiction of the cystic duct as compared with FSE MRCP with CS because shorter TE with GRASE allowed higher signal of the concentrated bile.

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Magnetic susceptibility of gallbladder stones
Rakesh Kumar Gupta1, Jaladhar Neelavalli2, Manoj Kumar3, Indrajit Saha4, Pradeep Kumar Gupta5, Jitender Saini6, and Sunita Ahlawat7

1Radiology, Fortis Memorial Research Institute, Gurgaon, India, 2Philips Innovation Campus, Philips India Limited, Bengaluru, India, 3Radiology, National Institute of Mental Health And Neurosciences, BENGALURU, India, 4Philips India Limited, Gurgaon, India, 5Fortis Memorial Research Institute, Gurgaon, India, 6Radiology, National Institute of Mental Health And Neurosciences, Bengaluru, India, 7Surgery, Fortis Memorial Research Institute, Gurgaon, India

Quantification of volume magnetic susceptibility of extracted gallbladder stones, with 28 different types of textures, was performed using quantitative susceptibility mapping. Both dia- and para-magnetic stones are seen and the susceptibility values were found to be comparable in magnitude to those found in venous vessels and blood products –  and hence could be detected in-vivo using SWI. This is in agreement with a recent work reporting visualization of gall-stones using SWI. 

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High-fat stimulation in healthy subjects: Longitudinal monitoring of bile acid and diffusivity changes in the gallbladder by MRS and MRI
Peter Vermathen1, Dino Kroell2, Philipp Nett2, Guido Stirnimann2, and Reiner Wiest2

1DBMR & DIPR, University of Bern, Bern, Switzerland, 2Department of Visceral Surgery and Medicine, University Inselspital, Bern, Switzerland

Bile exerts multiple functions in the liver and gut and is a key player in disease processes. In this pilot study we implemented a standardized stimulation test with high-fat diet in lean physically fit individuals and performed MRS and MRI measurements longitudinally to monitor bile acid composition and diffusivity changes in the gallbladder, with the long term aim to determine a specific bile-acid-microbiota “signature”. Strongly increased bile acid and lipid resonances and reduced diffusivity after lipid ingestion were determined as well as reversal to base values within 24h, demonstrating the feasibility and potential of the method.

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Artifacts in the arterial phase during gadoxetic-acid-enhanced MRI: multiple arterial phases versus single arterial phase from two different vendors
shuangshuang xie1, hanxiong qi1, Qing Li1, Kun Zhang1, Jinxia Zhu2, and Wen Shen1

1Tianjin First Center Hospital, Tianjin, China, 2MR Collaboration, Siemens Healthcare, Beijing, China

In this article, we compare the usefulness of multiple arterial phases (APs) and a relatively short breath-hold single AP to reduce the motion artifact in gadoxetic-acid-enhanced MRI. The transient motion artifact (TMA) score and phase timing of the AP in 540 consecutive patients were retrospectively analyzed. Our results showed that the best mean TMA score for multiple APs was significantly lower than that for the conventional single AP, but a relatively short breath-hold single AP did not reduce the incidence of TMA. In addition, multiple APs can capture more satisfactory ones, which meets clinical diagnostic requirements.

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Breathhold Black Blood Quantitative Parametric Imaging of the Liver Using Magnetization Prepared Single Shot Fast Spin Echo with DANTE Preparation
Jian Hou1, Baiyan Jiang1, Weibo Chen2, Queenie Chan3, and Weitian Chen1

1Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong, 2Philips Healthcare, Shanhai, China, 3Philips Healthcare, Hong Kong, China, Hong Kong, Hong Kong

Chronic liver disease is a major healthcare problem worldwide. Liver fibrosis is a key pathogenic and prognostic feature in most chronic liver diseases. It is reported that T1rho has the potential for detection of liver fibrosis. However, the rich blood signal in the liver can confound T1rho quantification of liver tissue. In this work, we investigate single shot fast spin echo acquisition with the delay alternating with nutation for tailored excitation (DANTE) preparation as a solution to this problem. 

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Breath hold free hepatobiliary phase imaging: usefulness of stack-of-stars acquisition
Shintaro Ichikawa1, Utaroh Motosugi1, Marie-Luise Kromrey1,2, Daiki Tamada1, Tetsuya Wakayama3, Kang Wang4, Ty Cashen4, Ali Ersoz5, and Hiroshi Onishi1

1Department of Radiology, University of Yamanashi, Chuo-shi, Japan, 2Department of Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Greifswald, Germany, 3MR Collaboration and Development, GE Healthcare, Tokyo, Japan, 4MR Collaboration and Development, GE Healthcare, Madison, WI, United States, 5MR Engineering, GE Healthcare, Waukesha, WI, United States

We compared the quality of hepatobiliary phase (HBP) imaging using the prototype pulse sequences stack-of-stars liver acquisition with volume acceleration (LAVA) (LAVA Star) with or without navigator echoes (LAVA Starnavi+ and LAVA Starnavi-) and Cartesian LAVA with navigator echoes (Cartesian LAVAnavi+). LAVA Starnavi+ showed better image quality, liver edge sharpness, and hepatic vein clarify than others. The images of LAVA Starnavi+ had less streak artifacts than those of LAVA Starnavi- The use of both stack-of-stars acquisition and navigator echo is the best solution to obtain HBP images without breath hold in terms of quality of images.

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Interface Analysis of the Liver and Focal Hepatic Lesions in Hepatobiliary Phase Imaging: A Comparison between Free-breathing Radial and Conventional Breath-hold Acquisition Technique.
Nobuyuki Kawai1, Satoshi Goshima1, Yoshifumi Noda1, Kimihiro Kajita2, Hiroshi Kawada1, Yukichi Tanahashi1, Shoma Nagata1, and Masayuki Matsuo1

1Department of Radiology, Gifu University, Gifu, Japan, 2Department of Radiology services, Gifu University, Gifu, Japan

The free-breathing radial k-space sampling technique is especially useful for patients with limited breath-holding capacity in liver MR imaging, however, its degradation of spatial resolution in the plane compared with the Cartesian sampling is the greatest disadvantage. We assessed the fat-suppressed three-dimensional T1-weighted fast field echo imaging with pseudo-golden-angle radial stack-of-stars sampling technique with gate and track (3D-VANE) compared with the conventional breath-hold Cartesian sampling (BH-eTHRIVE) in hepatobiliary phase imaging. Our results demonstrated that 3D-VANE with thinner effective slice thickness (thin-slice 3D-VANE) achieved comparable interface resolution, less artifact and better image quality compared with BH-eTHRIVE.

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Deep Learning Infrastructure for Fast Magnetic Resonance Imaging Annotation of Hepatocellular Carcinoma
Brett Marinelli1, Trevor Ellison1, Kaustubh Kulkarni1, Dudley Charles1, Bachir Taouli1, Anthony Costa1, and Edward Kim1

1Radiology, Mount Sinai, New York, NY, United States

Deep learning is an important tool that can help drive important new innovations in medicine, including in MRI tumor segmentation for HCC. Large annotated data sets will be needed for effective deep learning, however, current techniques are tedious and inefficient for annotating images on a large scale. We propose a streamlined infrastructure to optimize and standardize the process of anonymizing patient information, structuring the data, and annotating images efficiently. We show that our streamlined infrastructure increases the speed at which ground truth annotations can be generated.

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Dynamic contrast-enhanced MR imaging of hypervascular liver lesions: comparison of conventional breath-hold and a free-breathing acquisition technique with compressed sensing and motion-state-resolved reconstruction
Xiangtian Zhao1, Mengyue Huang2, Yingyu Che2, Jinxia Zhu3, Dominik Nickel4, and Jingliang Cheng2

1magnetic resonance imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 2Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, 3MR Collaborations, Siemens Healthcare, Ltd., Beijing, China, 4MR-Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany

We investigated a prototype free-breathing Cartesian volumetric interpolated breath-hold examination (VIBE) protocol with compressed sensing (CS) and motion-state-resolved reconstruction as extra-dimension (XD-VIBE) for Gd-DTPA-enhanced dynamic liver imaging by comparing it with conventional breath-hold VIBE. We found that it provided good image quality and diagnostic performance for hypervascular liver lesion detection except for the pre-contrast phase. This is a promising option for patients with poor breath-holding capacity.

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Motion-Robust and Blood-Suppressed M1-Optimized Diffusion MR Imaging of the Liver
Yuxin Zhang1,2, Óscar Peña-Nogales3, 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, 3Laboratorio de Procesado de Imagen, Universidad de Valladolid, Valladolid, Spain

Liver DWI is complicated by multiple challenges, including the relatively short T2 of liver tissue and the motion sensitivity of diffusion encoding sequences. In this study, a novel approach for the design of diffusion weighting waveforms, termed M1-Optimized Diffusion Imaging (MODI), is proposed for motion-robust, blood-suppressed liver DWI. MODI includes an echo-time optimized motion-robust diffusion weighting gradient waveform design, with a moderate non-zero first-moment (M1≠0) value to enable blood signal suppression. This work describes the proposed MODI method, and evaluates its effectiveness in healthy volunteers as well as in patients.

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The magnetic resonance elastography of liver for patients with Gaucher disease after enzyme replacement therapy
Di Li1, Yang Fan2, juan xiao tao1, and Yun Peng1

1Beijing Children's Hospital, Capital Medical University, Beijing, China, 2GE Healthcare China, Beijing, China

Gaucher disease (GD) is one of the most prevalent lysosomal storage disorders, which may lead to long term liver complications including fibrosis and cirrhosis. At present, enzyme replacement therapy (ERT) is widely used for GD in clinic.Magnetic resonance elastography (MRE) is the most accurate noninvasive technique for detection and staging of liver fibrosis.No significant difference was detected for GD patients after ERT in this study. It may indicate that enzyme replacement therapy is effective for most patients. 

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Patient free-breathing Quantitative T2 Mapping in the Pancreas
Naik Vietti Violi1, Tom Hilbert1,2,3, Jessica AM Bastiaansen1, Jean-Francois Knebel1,4, Jean-Baptiste Ledoux1,4, Alto Stemmer5, Reto Meuli1, Tobias Kober1,2,3, and Sabine Schmidt1

1Radiology, Lausanne university hospital, Lausanne, Switzerland, 2Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, 3LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 4Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, 5Siemens Healthcare GmbH, Erlangen, Switzerland

In this study, we test the feasibility of free-breathing quantitative T2 measurement in the pancreas and we correlate T2-values with demographical and clinical parameters in 88 patients whom were subject to a liver MRI. We found that using a 10-fold accelerated multi-echo-spin-echo MRI prototype sequence at 3T, we were able to measure pancreatic T2-values in a short acquisition time, with low variability and a good inter-reader agreement. We found significant differences in T2-values depending on age, measurement location, main pancreatic duct dilatation and diffuse pancreatic disease.

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Real World Experience Measurement of R2 vs R2 star in Hemoglobinopathies
Riad Abou Zahr1, Barbara E U Burkhardt2, Lubaina Ehsan3, Zora R Rogers4, and Tarique Hussain5

1Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Universitäts- Kinderspital Zürich – Eleonorenstiftung, Zurich, Switzerland, 3Medical College, Aga Khan University, Karachi, Pakistan, 4Pediatrics (Hematology/Oncology), University of Texas Southwestern Medical Center, Dallas, TX, United States, 5Pediatrics & Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States