Ahmed Bayoumi1, Hasan Khader2, John Lincoln1
1Department of Neurology, 2Department of Diagnostic and Interventional Imaging, McGovern Medical School at UTHealth Houston
Objective:
To asses glymphatic system function in multiple sclerosis (MS) among other neuroinflammatory and neurodegenerative imaging correlates, and evaluate glymphatic measures compared to established MS imaging markers as a classifier of people with MS (PwMS) with lower and higher disability.
Background:
The role of the glymphatic system in MS-related disability is under-explored. Diffusion-tensor image analysis along the perivascular space (DTI-ALPS) offers a non-invasive method to assess the glymphatic system function.
Design/Methods:
This retrospective study included 118 PwMS who underwent clinical evaluation including assessment of Expanded Disability Status Scale (EDSS) scores, as well as structural and diffusion-weighted magnetic resonance imaging. The participants were divided into lower (MS-L) and higher disability (MS-H) groups using an EDSS milestone of 3. The structural images underwent lesion segmentation and spatial normalization estimating white matter hyperintense lesion load (LL) and brain parenchymal fraction (BPF). DTI-ALPS indices were calculated using the diffusion-weighted images. Correlations between DTI-ALPS index, clinical and imaging measures were calculated. Multivariate logistic regression was performed to evaluate LL, BPF, and DTI-ALPS index in classifying lower and higher disability PwMS.
Results:
MS-L (EDSS < 3) included 57 PwMS (mean age: 43.2 ± 12.1; 50.9% female), and MS-H (EDSS ≥ 3) included 61 PwMS (mean age 46.7 ± 11.4; 78.7% female). DTI-ALPS index correlated significantly with disease duration (rp = -0.29, false-discovery rate adjusted p-value (p-FDR) = 0.002) and EDSS (rsp = -0.35, p-FDR = 0.0002). It also showed significant correlations with LL and BPF. DTI-ALPS index and LL were significant classifiers of PwMS into lower and higher disability (DTI-ALPS: odds ratio (OR) = 1.77, p = 0.04, LL: OR = 0.94, p = 0.02).
Conclusions:
Our findings highlight DTI-ALPS index as a possible imaging biomarker in MS, suggesting a role for glymphatic impairment in MS pathology, although further research is needed to elucidate its role in contributing to MS-related disability.
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