Acquired immunodeficiency syndrome. Magnetic resonance patterns of brain involvement with pathologic correlation.

Magnetic resonance brain scans of 30 patients with either acquired immunodeficiency syndrome (AIDS) or AIDS-related complex were reviewed. Twenty patients had focally abnormal neurological examination results at the time of scanning. Pathological diagnosis was available in nine. Four patterns of abnormality were observed on T2-weighted images. Multiple discrete high-signal foci (pattern A) were found in patients with toxoplasmosis and progressive multifocal leukoencephalopathy. Large, bilateral patchy to confluent high-signal areas within the white matter (pattern B) represented a white matter encephalitis secondary to cytomegalovirus or human immunodeficiency virus. Generalized enlargement of the cortical sulci and ventricles (pattern C) probably reflected atrophic changes from the chronic human immunodeficiency virus infection and prolonged debilitating illness. Solitary high-signal-intensity lesions (pattern D) suggested a nonviral opportunistic infection. Differential diagnosis of brain abnormalities in patients with AIDS can be assisted by recognition of these characteristic patterns.