Baseline MRI characteristics of patients at high risk for multiple sclerosis: results from the CHAMPS trial. Controlled High-Risk Subjects Avonex Multiple Sclerosis Prevention Study.

The baseline MRI studies from the Controlled High-Risk Subjects Avonex Multiple Sclerosis Prevention Study (CHAMPS) trial, a randomized, longitudinal, double-blind trial of 383 patients with a first acute clinical demyelinating event and evidence of prior subclinical demyelination on magnetic resonance imaging (MRI) of the brain, provides a large MRI database for patients likely in the earliest stages of multiple sclerosis (MS). High-resolution baseline MRIs revealed a median of 13 T2 lesions (maximum = 103 lesions) and 2.05 cm3 of T2 lesion volume (maximum 35.04 cm3), with 30% of patients having one or more enhancing lesions despite receiving a standardized high-dose course of intravenous corticosteroids. Periventricular, discrete, and juxtacortical T2 lesions were present in 99%, 92% and 67% of the patients, respectively. Large (> 6 mm), T1-hypointense, infratentorial, and corpus callosum lesions were present in 69%, 50%, 55% and 58%, respectively. Clinical presentation groups showed differences in T2 lesion volume, and enhancing lesion number and volume. At baseline, 97%, 81% and 72% of the patients met 'Paty', 'Fazekas', and 'Barkhof' research criteria for MS, respectively, with the percentages similar according to clinical presentation group. These results support and extend those of smaller and/or retrospective series, which have shown substantial subclinical injury, based on brain MRI, at the earliest identifiable stages of disease.