Acute disseminated encephalomyelitis. MRI findings and the distinction from multiple sclerosis.

Brain MRI was performed on 12 patients with acute disseminated encephalomyelitis (ADEM). Multifocal white matter lesions indistinguishable from those seen in multiple sclerosis (MS) were found in 10. In 5 there were rather extensive symmetric abnormalities in the cerebral (2) or cerebellar white matter (2), or basal ganglia (1). Follow-up MRI after intervals of 2 wks to 18 months demonstrated partial resolution of the abnormalities, but some persisting lesions. New MRI lesions were found at follow-up in only 1 case after an interval of 2 wks. Serial MRI makes a useful contribution to the distinction between MS and ADEM.