Thalamic Nuclei Volumes and Their Relationships to Neuroperformance in Multiple Sclerosis: A Cross-Sectional Structural MRI Study.

BACKGROUND Although reduced thalamic volume is associated with multiple sclerosis (MS)-related clinical impairment, the role of individual thalamic nuclei remains poorly understood. PURPOSE/HYPOTHESIS To test whether individual thalamic nuclei volumes are more strongly associated with clinical disability than the whole thalamic volume. STUDY TYPE Retrospective analysis of a prospective dataset. SUBJECTS A total of 108 MS patients and 48 age- and sex-matched healthy controls (HCs) FIELD STRENGTH: 3T. SEQUENCES 3D T1 -weighted inversion recovery spoiled gradient echo; 2D T2 -weighted fluid-attenuated inversion recovery spin echo; 2D dual-echo proton density-weighted/T2 -weighted spin echo. ASSESSMENTS Clinical assessments included the Expanded Disability Status Scale (EDSS), Nine-Hole Peg Test (9HPT), Timed 25-Foot Walk (T25FW), Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMTR), and the California Verbal Learning Test (CVLT2). FreeSurfer provided anterior, intralaminar, lateral, medial, ventral, posterior, and total volumes. STATISTICAL TESTS False discovery rate-corrected partial correlations (controlling for age, sex, and education) to assess the relationships between volumes and neuroperformance. RESULTS Compared to HCs, MS patients presented with lower thalamic nuclei volumes (P < 0.05) except for the intralaminar nucleus (P = 0.279) and scored worse on all neuroperformance scales (P ≤ 0.05) except for CVLT2 (P = 0.151). All nuclei except intralaminar were associated with EDSS (correlation coefficient range: -0.233 to -0.395), SDMT (range: 0.247-0.423), and 9HPT (range: -0.232 to -0.303) (all P < 0.05). BVMTR was associated with anterior (r = 0.319), lateral (r = 0.31), and medial (r = 0.304) volumes (all P < 0.05). T25FW correlated with ventral (r = -0.392) and total (r = -0.309) volumes (both P < 0.05), with the latter being significantly greater (P < 0.05). DATA CONCLUSION Assessing individual nuclei volume can aid in unraveling the relationship between thalamic pathology and disparate aspects of MS-related disability. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY STAGE: 2.