Brain lesions in patients with AIDS: H-1 MR spectroscopy.

PURPOSE: To evaluate the role of proton (hydrogen-1) magnetic resonance (MR) spectroscopy in the differential diagnosis of focal brain lesions in patients with acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: Twenty-six men with 35 AIDS-related brain lesions underwent MR imaging and localized H-1 MR spectroscopy. Lesions consisted of 11 toxoplasmic abscesses, 12 progressive multifocal leukoencephalopathic lesions, eight lymphomas, and four cryptococcomas. Metabolite peak areas in the lesions were compared with those in the contralateral hemisphere in each patient. RESULTS: H-1 MR spectroscopic findings showed significantly different biochemical profiles for each diagnostic group (P = .0001) with regard to N-acetyl compounds, total creatine pool, choline-containing compounds, myoinositol, and lactate. H-1 MR spectroscopy alone helped correctly diagnose 94% (84% with jackknifed classification) of the brain lesions, without overlap between toxoplasmosis and lymphoma. CONCLUSION: H-1 MR spectroscopy is a sensitive and potentially specific noninvasive adjunctive method for differential diagnosis of focal brain lesions in AIDS.