Brain Proton Magnetic Resonance Spectroscopy in HIV-Related Encephalopathy: Identification of Evolving Metabolic Patterns in Relation to Dementia and Therapy

Abstract

Proton MRS has proved useful in the early diagnosis of HIV-related encephalopathy. The modifications of brain metabolism in HIV-related encephalopathy 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 their evolution under zidovudine treatment. We have examined 112 HIV patients--35 neuroasymptomatic patients and 77 patients with ADC (AIDS dementia complex)--with localized proton MRS, using the PRESS 135-msec sequence. We have found the same metabolic modifications in N-acetylaspartate and choline-containing compounds as described in the literature. In addition, 14% of HIV patients with normal MRI displayed abnormal MRS, whatever their neurological status. The MRS-added diagnostic value in neuroasymptomatic patients reaches 30 %. The occurrence of undifferentiated (modification of NAA/Cho ratio only) and Cho (mainly an increase in choline signal) patterns is not significantly different in neuroasymptomatic and ADC patients. The NAA pattern (mainly a significant loss 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 ratio) is related to the occurrence of NAA loss (in NAA and double patterns). An MRS follow-up study of 11 HIV patients showed that the clinical outcome was favorable after a 1000-mg/day zidovudine treatment in patients displaying an NAA pattern whereas this treatment had no effect on the patients displaying the Cho pattern. Consequently, MRS appears to be of great interest in predicting responsiveness to antiretroviral drugs and detecting early any resistance to treatment.

Assessing multiple-group diagnostic problems with multi-dimensional receiver operating characteristic surfaces: Application to proton MR Spectroscopy (MRS) in HIV-related neurological injury

“…The same AUC corresponding to the comparison between NAS and ADC is 0.68. This suggests a trend between the three groups and is consistent with reports of persistent brain tissue inflammation at all stages of HIV infection (Glass et al 1993;Jarvik et al 1993;Jarvik et al 1996;Tracey et al 1996;LopezVillegas et al 1997;Salvan et al 1997;Chang et al 1999). The areas under the ROC curves associated with MI/Cr levels in the basal ganglia were 0.65 corresponding to the NEG versus NAS comparison and 0.73 in the NEG versus ADC comparison, suggesting that glialcell metabolism (gliosis) may be increasing in conjunction with observable, overt neurological impairment.…”

A prepro-orexin gene polymorphism is associated with narcolepsy

“…This study confirms reported metabolic abnormalities of HIV encephalopathy, [8][9][10] with decreased N-acetylaspartate and increased choline, and underscores their regional (frontal) or diffuse distribution. The longitudinal evaluation demonstrated that HAART partially reverses both clinical and metabolic abnormalities.…”

Discrepancy between Blood and Cerebral Didanosine Effects in HIV Patients: A Magnetic Resonance Spectroscopy Study

“…Brain metabolic profi les, obtained from qualitative MRS clinical reports, were analyzed according to the , respectively, in patients with normal and abnormal MRS and the median viral load values were 1,408 copies/ml and 119,860 copies/ml, respectively, whatever the treatment was. These results are in agreement with previous studies [3,5,6] . …”