super(18)FDG PET-CT imaging detects arterial inflammation and early atherosclerosis in HIV-infected adults with cardiovascular disease risk factors

Background: Persistent vascular inflammation has been implicated as an important cause for a higher prevalence of cardiovascular disease (CVD) in HIV-infected adults. In several populations at high risk for CVD, vascular super(18)Fluorodeoxyglucose ( super(18)FDG) uptake quantified using 3D-positron emission-computed tomography (PET-CT) has been used as a molecular level biomarker for the presence of metabolically active proinflammatory macrophages in rupture-prone early atherosclerotic plaques. We hypothesized that super(18)FDG PET-CT imaging would detect arterial inflammation and early atherosclerosis in HIV-infected adults with modest CVD risk. Methods: We studied 9 HIV-infected participants with fully suppressed HIV viremia on antiretroviral therapy (8 men, median age 52 yrs, median BMI 29 kg/m super(2), median CD4 count 655 cells/[mu]L, 33% current smokers) and 5 HIV-negative participants (4 men, median age 44 yrs, median BMI 25 kg/m super(2), no current smokers). Mean Framingham Risk Scores were higher for HIV-infected persons (9% vs. 2%, p < 0.01). super(18)FDG (370 MBq) was administered intravenously. 3D-PET-CT images were obtained 3.5 hrs later. super(18)FDG uptake into both carotid arteries and the aorta was compared between the two groups. Results: Right and left carotid super(18)FDG uptake was greater (P < 0.03) in the HIV group (1.77 plus or minus 0.26, 1.33 plus or minus 0.09 target to background ratio (TBR)) than the control group (1.05 plus or minus 0.10, 1.03 plus or minus 0.05 TBR). super(18)FDG uptake in the aorta was greater in HIV (1.50 plus or minus 0.16 TBR) vs control group (1.24 plus or minus 0.05 TBR), but did not reach statistical significance (P = 0.18). Conclusions: Carotid artery super(18)FDG PET-CT imaging detected differences in vascular inflammation and early atherosclerosis between HIV-infected adults with CVD risk factors and healthy HIV-seronegative controls. These findings confirm the utility of this molecular level imaging approach for detecting and quantifying glucose uptake into inflammatory macrophages present in metabolically active, rupture-prone atherosclerotic plaques in HIV infected adults; a population with increased CVD risk.