18F-FDG PET has incremental value compared to traditional atherosclerotic imaging in HIV-positive patients

Objectives To compare 18F-FDG standardized uptake values (SUV) in the aorta with intima media thickness and calciumscore in HIV-positive patients since previous studies have shown that HIV-positive patients have a high prevalence of silent myocardial ischemia despite normal carotid intima media thickness and coronary calcium score.

Methods Fifteen HIV-positive patients without known or suspected atherosclerotic disease were included. Real-time IMT was measured in the common carotid artery 1 cm caudal of the bulbus. On the same day patients underwent combined PET/CT 3 hours after injection of 400 MBq 18F-FDG. The aorta was manually traced on 15 slices covering both the aorta thoracalis and the aorta abdominalis. SUVmean and SUVmax were recorded as the mean of values on all traced slices. Calcification was assessed on axial CT scans of the carotid arteries and the aorta using a modified Agatston score.

Results All patients were male with a median age of 55 years (range 30 to 73) and a median body mass index of 24 (IQR 22-29). Four (27%) were smokers and none had hypertension, diabetes or hypercholesterolemia. Median hsCRP was 1.64 mg/L (IQR 1.44 - 4.54). Median SUVmax in the aorta was 1.52 (range 1.24-2.19) and median SUVmean in the aorta was 0.85 (range 0.61 to 1.07). Neither SUVmax nor SUVmean correlated with carotid intima media thickness (r=0.1 and -0.03) or calcium score (r=0.3 and 0.3).

Conclusions FDG uptake in the wall of the aorta has independent information compared to both calcium scoring in the aorta and intima media thickness in the carotid arteries in HIV positive patients without known or suspected cardiovascular disease. Future studies will show if this incremental value will translate into important prognostic information if HIV-positive patients