A longitudinal study of brain atrophy in relapsing multiple sclerosis

Objective: To determine if progressive brain atrophy could be detected over 1- and 2-year intervals in relapsing MS, based on annual MR studies from t he Multiple Sclerosis Collaborative Research Group (MSCRG) trial of interfe ron beta-1a (Avonex). Methods: All subjects had mild to moderate disability , with baseline expanded disability status scores ranging from 1.0 to 3.5, and at least two relapses in the 3 years before study entry. Atrophy measur es included third and lateral ventricle width, brain width, and corpus call osum area. Results: Significant increases were detected in third ventricle width at year 2 and lateral ventricle width at 1 and 2 years. Significant d ecreases in corpus callosum area and brain width were also observed at 1 an d 2 years. Multiple regression analyses suggested that the number of gadoli nium-enhancing lesions at baseline was the single significant contributor t o change in third ventricle width. Atrophy over 1 and 2 years as indicated by enlargement of the third and lateral ventricle and shrinkage of the corp us callosum was greater for patients entering the trial with enhancing lesi ons. Greater disability increments over 1 and 2 years were associated with more severe third ventricle enlargement. Conclusion: In patients with relap sing MS and only mild to moderate disability, significant cerebral atrophy is already developing that can be measured over periods of only 1 to 2 year s. The course of cerebral atrophy in MS appears to be influenced by prior i nflammatory disease activity as indicated by the presence of enhancing lesi ons. Brain atrophy measures are important markers of MS disease progression because they likely reflect destructive and irreversible pathologic proces ses.