PURPOSE: To investigate cerebral metabolic changes in acquired immunodeficiency syndrome dementia complex (ADC) with proton magnetic resonance (MR) spectroscopic imaging and compare the findings with those of conventional MR imaging. MATERIALS AND METHODS: Seven patients with ADC (all men; age range, 33-58 years; mean, 43 years) with human immunodeficiency virus (HIV) infection and seven age-matched volunteers without HIV infection underwent spectroscopic and conventional MR imaging. RESULTS: Patient spectra were characterized by reduced levels of N-acetyl aspartate and increased levels of choline in white-matter regions. Lactate was detected in the cerebrospinal fluid of five patients. Four patients with mild to moderate dementia had more extensive metabolic abnormalities than three patients with only mild neurocognitive changes. CONCLUSION: Proton MR spectroscopic imaging shows extensive metabolic changes and is more sensitive than conventional MR imaging in the detection of central nervous system involvement in ADC.