Objectification and Quantification of the Cognitive Impairment from an Existing HIV Infection or HIV Encephalopathy Using Magnetic Resonance Spectroscopy

Abstract

Some patients with HIV develop dementia. Using in vivo proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy, it is possible to measure the metabolic changes noninvasively. In this study, it is of interest to answer the clinically relevant question of whether magnetic resonance spectroscopy is suitable for the diagnosis of HIV encephalopathy. In total, 14 HIV-positive patients were investigated by means of localized 1 H-NMR spectroscopy in the following locations: (1) the mid-parietal gray matter, (2) the parietal white matter (PWM), and (3) the frontal white matter. All patients had no other brain diseases, apart from the HIV encephalopathy. The clinical extent of HIV encephalopathy of each patient was investigated using the following tests: (1) an electroencephalogram, (2) a neurological examination and psychiatric assessment, and (3) a psychometrical test. The spectroscopic changes in the PWM were more pronounced than those in the cortex, and the myo-inositol/creatine (mI/Cr) signal showed a clear increase in the cortex. Overall, the mI/Cr ratio emerged as the most reliable and earliest parameter to indicate an HIV encephalopathy.