The influence of clinical relapses and steroid therapy on the development of Gd-enhancing lesions: a longitudinal MRI study in relapsing-remitting multiple sclerosis patients.

Fifty-three patients with relapsing-remitting multiple sclerosis who had monthly Gd (gadolinium) enhanced MRI (Magnetic Resonance Imaging) and clinical evaluation, were divided into two subgroups: 1) patients with a clinical relapse, treated with IVMP (intravenous methylprednisolone) and at least one enhancing lesion on MRI. 2) patients who did not have a clinical relapse but with at least one enhancing lesion on MRI. In group 1, we evaluated the number and volume of enhancing lesions on the scan before and three scans after IVMP therapy; in group 2, we considered the first scan with enhancing lesions and the subsequent three scans. The mean number and volume of enhancing lesions on the first scan was significantly higher in patients with clinical relapse compared to patients without clinical relapse. In group 1, we found a consistent reduction in the first scan following steroid treatment which returned to initial levels at the following scan. Both volumetric and numerical evaluation are appropriate MRI outcome measures in monitoring therapeutic trials.