Perivascular Diffusivity and Periventricular Susceptibility Changes in Relapsing–Remitting Multiple Sclerosis: A Combined
DTI
‐
ALPS
and
R. B. Revanth, K. A. Smitha, S. S. Jithin, Pandi Meena, Sruthi S. Nair, E. R. Jayadevan, Bejoy Thomas, C. Kesavadas ABSTRACT
Background
Progressive periventricular damage in multiple sclerosis (MS) has been linked to impaired perivascular clearance and to susceptibility changes attributed to iron deposition and myelin loss. Their relationship is unclear.
Purpose/Hypothesis
To compare diffusion tensor image analysis along the perivascular space (DTI‐ALPS) and periventricular quantitative susceptibility mapping (QSM) between relapsing–remitting multiple sclerosis (RRMS) patients and healthy controls; and to evaluate their correlation and relationships with clinical disability (Expanded Disability Status Scale, EDSS).
Study Type
Retrospective case–control study.
Population/Subjects
Thirty one patients with RRMS (mean age, 34.6 ± 8.4 years) and 30 age‐ and sex‐matched healthy controls (mean age, 34.2 ± 8.1 years).
Field Strength/Sequence
1.5 T; Diffusion tensor imaging (DTI) and multi‐echo gradient‐echo (GRE) sequences.
Assessment
DTI‐ALPS index and periventricular QSM values were measured from manually placed bilateral regions of interest (ROIs). Standardized Montreal Neurological Institute (MNI)‐space coordinates were used for DTI‐ALPS analysis, and QSM ROIs in periventricular normal‐appearing white matter were reviewed by a neuroradiologist. Disability was assessed using the EDSS.
Statistical Tests
Groups were compared using independent‐samples t ‐tests and Cohen's d. Correlations were assessed using Pearson's r, with Spearman's rho as a sensitivity analysis ( p < 0.05, two‐tailed).
Results
DTI‐ALPS was lower in MS patients than controls (1.27 ± 0.22 vs. 1.45 ± 0.22; d = 0.828), whereas periventricular QSM was higher (−15.35 ± 4.92 vs. −21.70 ± 6.40 ppb; d = 1.116). A strong negative correlation between the two biomarkers was observed across all subjects ( r = −0.738). Both measures correlated with EDSS (DTI‐ALPS r = −0.509; QSM r = 0.501) and differed between EDSS subgroups (EDSS > 2.0 vs. ≤ 2.0: DTI‐ALPS 1.160 vs. 1.364; QSM −12.33 vs. −17.83 ppb).
Data Conclusion
Reduced DTI‐ALPS and higher periventricular QSM‐derived susceptibility were each moderately associated with disability in RRMS. The negative DTI‐ALPS–QSM correlation in both groups indicates an association between perivascular diffusivity, a putative marker of glymphatic function, and periventricular QSM‐derived susceptibility; causality cannot be established from this cross‐sectional design.
Level of Evidence
3.
Stage of Technical Efficacy
2.