Parole chiave: risonanza magnetica, AIDS, encefalopatia, encefalo.RIASSUNTO -55 pazienti con encefalopatia da AIDS sono stati esaminati con nsonanza magnetica, con apparecchiatura ad alto campo (1,5 tesla). 37 pazienti (67%) presentavano lesioni della sostaza bianca, 23 (41 %) atrofia, 7 (12%) avevano neurotoxoplasmosi, 2 (3,5%) criptococcosi e 2 (3,5%) erano affetti da linfoma.Dei 37 pazienti con lesioni della sostanza bianca, 20 (54%) mostravano diffusa iperintensita in DP e T2 e 17 (46%) lesioni focali.Nei 23 pazienti con atrofia, 12 (52%) presentavano atrofia cerebrale corticale, 8 (34%) atrofia cerebellare e del tronco e 7 (30%) atrofia diffusa.Dei 7 pazienti con neurotoxoplasmosi, 5 (72%) presentavano lesioni di tipo nodulare e 2 (28%) un quadro di encefalopatia diffusa.I due pazienti con linfoma presentavano un reperto di massa periventricolare. Nei due pazienti con criptococcosi e stato rilevato un aspetto nodulare a diffusione leptomeningea. Scopo di tale lavoro e quello di correlare le alterazioni encefaliche nei pazienti con AIDS al quadro RM.Tale studio e stato condotto su 55 pazienti esaminati tra il Marzo e l'Ottobre 1991, nel reparto di SUMMARY -55 patients with AIDS related encephalopathy were examined by means of high field magnetic resonance (1,5 tesla-Siemens Magnetom). 37 (67%) of the patients had white matter lesions, exhibited as areas of high signal intensity on PD e T2-weighted images, 23 ( 41%) of the patients showed atrophy, 7 ( 12 %) had neurotoxoplasmosis, 2 (3,5%) had criptococcosis and 2 (3,5%) were affected by lymphoma.Of the 37 patients who had white matter lesions, 20 (54%) showed diffuse high signal intensity while 17 ( 46%) exhibited focal lesions.Regarding the atrophy observed in 23 ( 41% ) of the patients, 12 (52%) had cortical cerebral atrophy and 7 ( 30%) showed diffuse atrophy.Of the 7 patients with neurotoxoplasmosis, 5 (72%) showed a nodular lesions pattern while 2 ( 28%) had a diffuse encephalopaty.In the 2 patients with lymphoma M R showed a mass lesion located in the periventricular region. The 2 patients with criptococcosis had leptomenigeal nodular lesions. The purpose of this study is to relate the brain lesions to the M R findings in 55 patients with AIDS, studiedfrom March to October 1991 at the MR department of the I Cl.