ABNORMAL CEREBRAL GLUCOSE-METABOLISM IN HIV-1 SEROPOSITIVE SUBJECTS WITH AND WITHOUT DEMENTIA

This study was undertaken in order to extend our previous finding of r elative basal ganglia hypermetabolism in AIDS dementia complex (ADC) a nd to develop clinically useful metabolic indices of CNS involvement i n HIV-seropositive (HIV+) subjects. Methods: Twenty-one HIV+ subjects (11 with AIDS) underwent FDG-PET scanning; 12 had a follow-up scan at 6 mo and 4 had a third scan at 12 mo. Forty-three age-matched heterose xual volunteers served as controls. FDG-PET scanning was performed wit h arterial blood sampling, and scan data were analyzed using the Scale d Subprofile Model (SSM) with principal component analysis. Results: S SM/principal component analysis of the combined (HIV+ and controls) FD G-PET dataset extracted two major disease-related metabolic components : (a) a nonspecific indicator of cerebral dysfunction, which was signi ficantly correlated with age, cerebral atrophy and ADC Stage and (b) t he striatum, which was heavily weighted (relatively hypermetabolic) an d appeared to provide a disease-specific measure of early CNS involvem ent. Conclusion: FDG-PET scans provide quantitative measures of abnorm al functional connectivity in HIV-seropositives-with or without AIDS o r ADC. These measures, which are robust across centers with respect to instrumentation, scanning technique and disease severity, appear to t rack the progression of CNS involvement in patients with subclinical n eurologic or neuropsychologic dysfunction.