The topographical distribution of tissue injury in benign MS: a 3T multiparametric MRI study.

We compared the global and regional distribution of white matter (WM) and gray matter (GM) damage and T2-visible lesion between patients with benign (B) and relapsing remitting (RR) multiple sclerosis (MS). BMS and RRMS patients did not differ in terms of global volumes and diffusion tensor (DT) MRI metrics of the WM and GM. Compared to controls, BMS and RRMS patients had bilateral thalamic loss. Compared to controls, BMS and RRMS patients had lower WM fractional anisotropy (FA) in the corpus callosum (CC) and in several regions of temporal and occipital lobes. BMS also had a decreased WM FA in the parietal lobes. RRMS patients had also lower WM FA in several regions of the frontal lobes. Compared to BMS, RRMS patients had decreased WM FA in the frontal lobes, while the opposite comparison showed lower WM FA in the CC, the temporal lobes and the cuneus in BMS. Contrasted to controls, both MS groups showed several regions of increased MD in WM and GM, but no difference was found between MS sub-groups. T2-visible lesions were mainly located in the posterior regions of the brain in BMS patients, while they involved also regions in the frontal lobes, in RRMS patients. BMS and RRMS patients differ in terms of the topographical distribution of WM damage rather than in the overall extent of brain structural changes. The less prominent involvement of the frontal lobe WM and of the NAWM in general in BMS might be associated to their favorable clinical status.