New MRI lesions and topography at 6 months of treatment initiation and disease activity during follow up in relapsing remitting multiple sclerosis patients

Objective: The objective of this study was to assess if the presence of new lesions and their topography on the reference MRI have a prognostic value regarding disease activity during the follow up in relapsing remitting multiple sclerosis (RRMS) patients. Methods: Retrospective cohort study that included patients with RRMS who had a reference MRI (performed at 6 months from the onset of a DMT) and radiological and clinical follow up for at least two years. We identified the number of new MRI lesions and their topography at reference MRI and during the follow up. Cox proportional hazards model analysis was used to evaluate the association between new lesions on reference MRI and the appearance of new lesions and/or clinical relapses at 24-month follow-up. Results: 56 patients were included, 13 (23.2%) showed new lesions in the reference MRI. The presence of new lesions at reference MRI predicted the occurrence of new lesions at month 24 (HR 3.1, CI 95% 2.5-5.8). The number of lesions and the infratentorial topography at reference MRI were associated with an increased risk of new radiological activity during follow up (HR 3.5, IC95% 3.1-6.1 and HR 2.4, IC95% 1.9-2.7 respectively). Conclusion: New lesions at the reference MRI in terms of number and topography increase the risk of radiological disease activity during the follow up.