Progressive cerebral atrophy in MS - A serial study using registered, volumetric MRI

Objective: To assess the potential of registered volumetric MRI in measurin g rates of atrophy in MS. Background: Pathologic and imaging studies sugges t that the development of permanent neurologic impairment in MS is associat ed with progressive brain and spinal cord atrophy. Atrophy has been suggest ed as a potential marker of disease progression. Conventional atrophy measu rements requiring manual outlining are time-consuming and subject to reprod ucibility problems. Registration of serial MRI may offer a useful alternati ve in that cerebral losses may be measured directly from automated subtract ion of brain volumes. Methods: Twenty-six patients with MS and 26 age- and gender-matched controls had two volumetric brain MR studies 1 year apart. B aseline brain and ventricular volumes were measured using semiautomated tec hniques, and follow-up scans were registered to baseline. Rates of cerebral atrophy were calculated directly from the registered scans. Results: Basel ine brain volumes in the MS group were smaller (mean difference 78 mL [95% CI 13 to 143; p = 0.02]) and ventricular volumes greater (mean difference 1 2 mL [95% CI 6 to 18; p < 0.001]) than controls. The rate of cerebral atrop hy in the MS group (0.8% per year) was over twice that of controls (0.3%), and the rate of ventricular enlargement was five times greater than the con trols (1.6 versus 0.3 mL/year). Conclusion: Progressive cerebral atrophy is an important feature of MS. Registration-based measurements are sensitive and reproducible, allowing progressive atrophy to be detected within 1 year and may have potential as a marker of progression in monitoring therapeuti c trials.