A prospective 18F-FDG PET/CT study of the neurometabolic effects in cocaine use and HIV infection

OBJECTIVES: HIV affects 36 million people globally with prevalence decreasing due to antiretroviral therapy (ART) and social awareness; transmission occurs during substance use. Cocaine usage independently affects brain activity and may result in reduced ART adherence. This study evaluates brain glucose metabolism measured by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in cocaine users with HIV infection.

DESIGN: Sixty-three subjects were categorized into groups: 36 HIV infected (HIV+) and 27 non-HIV infected (HIV-) subjects. Each group was further split into cocaine users (CO+) and non-cocaine users (CO-). Of the HIV+, half were cocaine users and half were not. Of the HIV-, 14 were cocaine users and 13 were not. 18F-FDG-PET and low dose CT scans were performed on all subjects.

METHODS: Brain glucose metabolism was evaluated by 18F-FDG uptake in the whole brain, cortex, basal ganglia, and cerebellum 120 minutes after injection. ROVER software was used for image analysis and ROI masks were applied via an adaptive threshold system. ANOVA tests and t-tests were performed to assess the respective differences between the four groups.

RESULTS: Generally, the HIV+/CO+ group (group A) displayed the lowest levels of uptake whereas the HIV-/CO- group (group D) showed the highest; the HIV+/CO- and HIV-/CO+ groups (group B and C) showed intermediate levels of activity across the whole brain, cortex, basal ganglia, and cerebellum.

CONCLUSION: HIV infection and cocaine usage were independently associated with a decrease in brain glucose uptake as measured by 18F-FDG PET/CT. When combined, positive HIV status and cocaine patients showed the most decreased 18F-FDG uptake.