BRAIN-LESIONS IN AIDS - WHAT CAN BE EXPEC TED FROM A SCINTIGRAPH - THALLIUM-201 SCINTIGRAPHY OF THE BRAIN - CONTRIBUTION TO DIFFERENTIAL-DIAGNOSIS OF LYMPHOMAS AND INFECTIOUS LESIONS

CT and MRI are not consistently able to differenciate central nervous system (CNS) lymphoma from focal cerebral infection such as toxoplasmo sis in the human immunodeficiency virus (HIV) involvement, In this stu dy thallium 201 (and/or technetium-MIBI) SPECT was performed in 6 pati ents suffering from AIDS and CNS lesions, An index based on the ratio of thallium uptake in the lesion vs the contralateral scalp was calcul ated. In 4 out of 5 patients with lymphoma (3 confirmed by biopsy, 2 h ighly suspected on CT and resistance to antitoxoplasmosis treatment) f ocal lesions showed high uptake of thallium. On the other hand one mar kedly necrotic lymphoma and all infectious lesions did not take up tha llium. This suggests a role for thallium 201 brain SPECT in the workup of focal CNS lesions in AIDS.