Relationship between brain MRI lesion load and short-term disease evolution in non-disabling MS: a large-scale, multicentre study

Background and Objectives: We evaluated clinical and conventional MRI features of a large population of patients with non-disabling MS to identify potential markers of a benign disease course. Methods: In seven MAGNIMS centres we retrospectively identified 182 patients with benign (B) MS (EDSS score <= 3.0, disease duration >= 15 years) and 187 patients with non-disabling relapsing-remitting MS (NDRRMS) (Expanded Disability Status Scale score >= 3.0, disease duration between 5 and 14 years), in whom clinical data were collected within two weeks from a brain T2-weighted scan. Brain T2 lesion volume (LV) was measured in all patients. In 146 BMS and 146 NDRRMS patients, clinical data were also available after a median follow up of 29 months (range: 7-104 months). Results: Mean LV was higher in BMS than in NDRRMS patients (p < 0.001), but the mean ratio between LV and disease duration was higher in NDRRMS than in BMS patients (1.1 vs. 0.6 ml/year, p < 0.001). In BMS patients, brain LV was correlated with EDSS score increase at follow up (r=0.18, p=0.03). Conclusions: An overall low rate of brain LV increase during a long-lasting disease course might be a feature of BMS. In BMS patients, a high brain LV might be associated with worsening of locomotor disability at short-term follow up.