[Neuro-AIDS: a multicenter neuroradiological study]

The results are described of a retrospective multicentric CT/MR study of 141 neuro-AIDS patients (IV group CDC classification); 114 patients were drug addicted, 13 homosexual, 8 polytransfused, and 6 had other risk factors. The mean age was 29.6 years. The pathologic agent was identified in 47 cases by c.s. fluid examination, biopsy, autopsy or specific treatment response: it was HIV in 20 cases, toxoplasmosis in 11, cryptococcosis in 9, leishmaniasis, salmonella and papovavirus in single cases. In the follow up of 2 cases, a Kaposi's sarcoma and a primitive CNS lymphoma occurred. The main clinical features were AIDS-dementia complex (45% of cases) and focal neurologic manifestations (36%). The neuroradiological protocol consisted of 238 CT exams (97 controls), most of them with DDD (delayed double dose) technique, 7 MR exams (0.15 T) and 2 angiographies. CT findings were divided into 3 groups: negative (16%), atrophic (47%) and focal lesions (37%). In the first and second group, HIV and cryptococcal infections were the main pathologic agents. In the third group toxoplasma infections were discovered, and TB granulomas and other pathologic conditions, with ring-like or nodular enhancement, in cortical/cortico-medullary location. In follow-up patients a high tendency of evolution towards focal lesions was observed, even in negative cases. The DDD enhancement technique allowed in most cases both the demonstration of very small lesions and their grading. According to the literature CT, though a highly sensitive method, is inferior to MR imaging; however our experience in this field is currently insufficient. The specific diagnosis of pathologic agents of neuro-AIDS is difficult, due to the high number of opportunistic AIDS-related infections and neoplasms, with overlapping features: differential diagnostic criteria can be assessed only by comparing the clinical, microbiological, topographic, CT and MR findings. CT and MR exams are necessary to guide and monitor therapy and to plan stereotaxis biopsy.