Elevated Corpus Callosum T1rho Reflects Disease Burden and Structural Atrophy in Multiple Sclerosis

Background/Objectives: Corpus callosum atrophy is a well recognized feature of multiple sclerosis (MS), which has been associated with disease duration and severity. Quantitative T1rho imaging is an MRI technique sensitive to microstructural tissue alterations, but the T1rho characteristics of the corpus callosum in MS remain largely unexplored. This study aimed to characterize T1rho in the corpus callosum in MS patients, and examine relationships between T1rho values, callosal atrophy, and clinical and imaging markers of disease burden. Method: Thirty patients with relapsing-remitting multiple sclerosis (RRMS) and 30 healthy controls underwent T1rho imaging. T1rho values were measured in the genu, body, splenium, and whole corpus callosum. Comparisons between patient and control groups were performed using the Mann–Whitney U test and the independent samples t-test, and Pearson’s and Spearman’s correlation coefficients were used to evaluate the correlation between imaging and clinical measures. Results: T1rho values were significantly increased across all corpus callosum subregions in patients compared to controls. Corpus callosum T1rho values showed correlations with disease duration (r = 0.375–0.408, p < 0.041), lesion load (r = 0.726–0.810, p < 0.001), and the corpus callosum index (CCI) (r = −0.731–−0.640, p < 0.001). Conclusions: T1rho values are elevated in the corpus callosum of MS patients and associated with disease duration, lesion load, and callosal atrophy.