BRAIN PROTON MAGNETIC-RESONANCE SPECTROSCOPY IN HIV-RELATED ENCEPHALOPATHY - IDENTIFICATION OF EVOLVING METABOLIC PATTERNS IN RELATION TO DEMENTIA AND THERAPY

Proton MRS has proved useful in the early diagnosis of HIV-related enc ephalopathy, The modifications of brain metabolism in HIV-related ence phalopathy can be classified according to different metabolic patterns (Vion-Dury J et al, CR Acad Sci 1994;317:833-840). The present study describes the relative occurrence of these patterns and evaluates thei r evolution under zidovudine treatment, We have examined 112 HIV patie nts-35 neuroasymptomatic patients and 77 patients with ADC (AIDS demen tia complex)-with localized proton MRS, using the PRESS 135-msec seque nce, We have found the same metabolic modifications in N-acetylasparta te and choline-containing compounds as described in the literature, In addition, 14% of HIV patients with normal MRT displayed abnormal MRS, whatever their neurological status, The MRS-added diagnostic value in neuroasymptomatic patients reaches 30 %. The occurrence of undifferen tiated (modification of NAA/Cho ratio only) and Cho (mainly an increas e in choline signal) patterns is not significantly different in neuroa symptomatic and ADC patients, The NAA pattern (mainly a significant la ss of NAA) is more frequent in ADC patients, Only ADC patients display the double pattern (with a significant increase in choline signal and a significant loss of NAA), Quantitated cerebral atrophy (bifrontal r atio) is related to the occurrence of NAA loss (in NAA and double patt erns), An MRS follow-up study of 11 HIV patients showed that the clini cal outcome was favorable after a 1000-mg/day zidovudine treatment in patients displaying an NAA pattern whereas this treatment had no effec t on the patients displaying the Cho pattern, Consequently, MRS appear s to be of great interest in predicting responsiveness to antiretrovir al drugs and detecting early any resistance to treatment.