PROSPECTIVE UTILITY OF CEREBRAL PROTON MAGNETIC-RESONANCE SPECTROSCOPY IN MONITORING HIV-INFECTION AND ITS ASSOCIATED NEUROLOGICAL IMPAIRMENT

Neurological manifestations of HIV disease occur in most adults and ch ildren with AIDS. Many of those affected will inevitably suffer clinic al neurological deficits involving mental function, movement, and sens ation. Surprisingly, there are not as yet adequate monitoring systems to predict the onset and/or progression of HIV infection of the CNS. N eurological, neuropsychological, CSF, and magnetic resonance imaging ( MRI) analyses cannot accurately detect mental deterioration during adv ancing HIV disease. Reports suggest that in vivo proton MR spectroscop y (H-1 MRS) of the brain could be a predictor of virus-induced neurolo gical deterioration.(1-5) H MRS can measure N-acetylaspartate (NAA), a metabolite present only in neurons. Decreased NAA reflects neuronal l oss seen during HIV infection of brain. To uncover possible associatio ns between NAA levels and HIV-induced neurological disease we performe d serial 1H MRS brain tests in HIV-infected patients with or at risk f or encephalopathy. Serial testing, for 1 year, of 10 patients showed t hat brain NAA levels decreased in all HIV-infected subjects. The most severe NAA reductions were associated with progressive neurological im pairment. These findings suggest that NAA can be used as a noninvasive measure of neuronal loss in patients with HIV disease. Most important , the results suggest that 1H MRS could be used to monitor therapeutic s directed against HIV infection within the CNS.