Evolution of different MRI measures in patients with active relapsing-remitting multiple sclerosis over 2 and 5 years: a case–control study

Background: There is growing evidence for the concept of multiple sclerosis (MS) as an inflammatory neurodegenerative disease, with a different pattern of atrophy evolution in grey matter (GM) and white matter (WM) tissue compartments. Objective: We aimed to investigate the evolution of different MRI measures in early relapsing-remitting patients with MS and in normal controls (NCs) over 2 years. We also evaluated the progression of these MRI measures in a subset of patients who were followed for up to 5 years. Methods: Included in this study were 147 patients who participated in the combination ASA (Avonex Steroids Azathioprine) study and completed full treatment, clinical and MRI assessment at 0, 12 and 24 months. A subgroup of 66 patients was followed for 36 months, 51 patients for 48 months and 43 patients for 60 months. Mean age at baseline was 30.7 years, mean disease duration was 5.5 years, mean EDSS was 1.8 and mean annualised relapse rate before study entry was 1.7. MRI scans were performed on a 1.5T scanner every 2 months for the first 2 years and thereafter once yearly for up to 5 years. In addition to the MS group, 27 NCs were examined at months 0, 12 and 24 using the same MRI protocol. Percentage brain volume change (PBVC), GM volume (GMV), WM volume (WMV) and peripheral grey volume (PGV) were measured annually using SIENA/X software. T2-hyperintense lesion volume (LV), lateral ventricle volume (LVV) and third ventricle width (3VW) were also assessed annually. Results: Over the period of 0–24 months, patients with MS lost significantly more GMV (−2.6% vs −0.72%, p<0.001), PGV (−2.4% vs −1.03%, p<0.001) and PBVC (−1.2% vs −0.22%, p<0.001), and increased in LVV (+16.6% vs +0.55%, p<0.003) and 3VW (+9.3% vs 0%, p = 0.003), when compared with NCs. Within-person change in MRI measures for patients with MS over 5 years was −4.2% for PBVC, −6.2% for GMV, −5.8% for PGV, −0.5% for WMV (all p<0.001), +68.7 for LVV (p<0.001), +4% for 3VW (p<0.001) and +42% for T2-LV (p<0.001). Conclusions: Our study confirmed a different pattern of GM, WM and central atrophy progression over 2 years between patients with MS and NCs. The study showed a different evolution of tissue compartment atrophy measures in patients with MS, with faster decline in cortical and deep GM regions, as well as periventricular WM regions, over a 5-year period.