Evolution of cortical and thalamus atrophy and disability progression in early relapsing-remitting MS during 5 years.

BACKGROUND AND PURPOSE Pathologic changes in GM have an important role in MS. We investigated the association between SDGM and cortical volume changes and disability progression in early RRMS. MATERIALS AND METHODS One hundred eighty patients with RRMS had clinical assessment during 5 years and were divided into those with or without SDP at 5 years by the usual definition in treatment trials. The number of available MR imaging scans at various time points was the following: at baseline, 178; and at 6 months, 172; at 12 months, 175; at 24 months, 155; at 36 months, 160; at 48 months, 158; and at 60 months, 162, respectively. Longitudinal changes in cortical, GM, and WM volume were calculated by using the direct method. RESULTS At 5 years, 90 patients with RRMS experienced SDP and 90 had stable disease. At baseline, patients with SDP had longer disease duration, greater T2-lesion volume, and smaller whole-brain, WM, cortical, and SDGM volume (P < .01). At 5 years, patients with SDP had significantly greater percentage decreases from baseline compared with those without SDP in the volume of the whole brain (P < .0001), cortex (P = .001), GM (P = .003), and thalamus (P = .01). In patients who developed SDP at 5 years and those who did not, mixed-effect models, adjusted for age, disease duration, and change of the treatment status, showed significant interactions between SDP status at 5 years and changes with time in whole-brain, cortical, lateral ventricle (all P < .001), thalamus (P = .006), and total SDGM (P = .0095) volume. CONCLUSIONS SDP is associated with progression of cortical, central, and thalamic atrophy in early RRMS during 5 years.