Differential diagnosis of CNS lesions in AIDS patients by FDG-PET

Objective: The aim of this study was to evaluate the potential of FDG-PET in the differential diagnosis of CNS lesions in patients with AIDS, particularly to differentiate between toxoplasmosis and lymphoma. Materials and Methods: We examined 11 AIDS patients, 6 with toxoplasmosis, 1 with a tuberculoma, and 4 with a primary CNS lymphoma. The FDG uptake within the lesion was compared with the uptake in a contralateral brain area [standardized uptake value (SUV)]. Results: In all subjects with cerebral infections (toxoplasmosis, tuberculoma), the SUV ratio was significantly (p < 0.05) lower than the SUV ratio in patients with lymphoma (range of 0.3-0.7 vs. 1.7-3.1) with no overlap of the uptake values. Conclusion: In conclusion, FDG-PET may help to characterize these lesions metabolically and play an important role in the clinical management of AIDS patients with CNS involvement.