CONICET | Buscador de Institutos y Recursos Humanos

Abstract The aim of the study was to analyze the differential brain volume changes in highly active multiple sclerosis (HAMS) vs. non-HAMS patients during the disease onset. Methods: a total of 64 adult multiple sclerosis (MS) patients were included. HAMS was defined as: a) patients with 1 relapse in the previous year and at least 1 T1 gadolinium-enhancing lesion or 9 or more T2 lesions while on therapy with other disease modifying treatment (DMD); or b) patients with 2 or more relapses in the previous year, whether on DMD or not. High-resolution T1-3D weighted MRI scans were acquired at baseline and every 12 months for 2 years. Brain volume measurements were determined on 3D T1 weighted images. At baseline, whole brain, gray matter (GM) and white matter (WM) tissue volumes were calculated using the SIENAX method. Longitudinal changes were assessed by the SIENA method in order to calculate the percentage of brain volume loss (PBVL). GM and WM volume changes were assessed by the SIENAX multi-time point method. Between-group volume differences were assessed by logistic regression analysis (p <0.05 significant). Results: 64 patients, mean age 38.4 years, 35 (57%) women were included. A total of 14 (21%) were classified as HAMS. At baseline, HAMS patients showed lower GM and WM volume compared with non-HAMS patients (p=0.003 and p=0.01, respectively). During the follow up, HAMS patients showed a higher decrease in GM volume compared with non-HAMS patients (-0.61 vs. ? 0.77, p <0.001) independent from new lesion in T2 as well as relapse rate activity during follow up. Conclusion: HAMS increased rates of GM atrophy over 24 months compared to non-HAMS patients independent from conventional disease activity (relapse rate and new T2 lesions).