Atherosclerotic plaque metabolism in high cardiovascular risk subjects – A subclinical atherosclerosis imaging study with 18F-NaF PET-CT

Abstract

Background and aimsAtherosclerotic plaque molecular imaging with 18F-sodium fluoride (NaF) in positron emission tomography with computed tomography (PET-CT) provides potential discrimination between active unstable microcalcification and established dormant calcification. We aimed to study 18F-NaF atherosclerotic plaque uptake in high cardiovascular (CV) risk participants and its associations with CV risk factors, coronary calcium score and thoracic fat volume. MethodsHigh CV risk hypertensive individuals from a single centre were prospectively scanned with 18F-NaF-PET-CT in the coronary, aortic and carotideal arteries. Atherosclerotic plaque 18F-NaF uptake was expressed as Corrected Uptake per Lesion (CUL): maximum standard uptake value in each vascular territory subtracted by mean blood pool activity. ResultsMean age was 64 years, 56% male and 96% Caucasian (n = 25). Ninety six per cent of the subjects showed 18F-NaF uptake in the aorta (CUL 0.9 ± 0.3), 40% in the carotid arteries (median CUL 0.0, IQR 0.0–0.7) and 64% in the coronary arteries (0.4, IQR 0.0–0.6). Individuals with ≥ five risk factors (60%) had increased overall 18F-NaF uptake (1.1 ± 0.3 vs. 0.7 ± 0.3, p < 0.01), which was positively correlated with predicted fatal CV risk - SCORE (r = 0.49, p = 0.01). There was no correlation between 18F-NaF uptake in the coronary arteries and calcium score (p = 0.87). Thoracic fat was moderately correlated with overall CUL (r = 0.41, p = 0.04). ConclusionsIn a high CV risk group, 18F-NaF atherosclerotic plaque uptake was related to the burden of CV risk factors and thoracic fat volume, but there was no association between coronary uptake and calcium score.