Detection of vulnerable atherosclerotic plaque and prediction of thrombosis events in a rabbit model using 18F-FDG -PET/CT.

Background: Detection of vulnerable plaques could be clinically significant in the prevention of cardiovascular events. We aimed to compare Fluorine-18 fluorodeoxyglucose ((18)F-FDG) uptake in vulnerable and stable plaques, and investigate the feasibility of predicting thrombosis events using Positron Emission Tomography/Computed Tomography (PET/CT) angiography.

Methods: Atherosclerosis was induced in 23 male New Zealand white rabbits. The rabbits underwent pharmacological triggering to induce thrombosis. A pre-triggered PET/CTA scan and a post-triggered PET/CTA scan were respectively performed. (18)F-FDG uptake by the aorta was expressed as maximal standardized uptake value (SUVmax) and mean SUV (SUVmean). SUVs were measured on serial 7.5 mm arterial segments.

Results: Thrombosis was identified in 15 of 23 rabbits. The pre-triggered SUVmean and SUVmax were 0.768 ± 0.111 and 0.804 ± 0.120, respectively, in the arterial segments with stable plaque, and 1.097 ± 0.189 and 1.229 ± 0.290, respectively, in the arterial segments with vulnerable plaque (P<0.001, respectively). The post-triggered SUVmean and SUVmax were 0.849 ± 0.167 and 0.906 ± 0.191, respectively in the arterial segments without thrombosis, and 1.152 ± 0.258 and 1.294 ± 0.313, respectively in the arterial segments with thrombosis (P<0.001, respectively). The values of SUVmean in the pre-triggered arterial segments were used to plot a receiver operating characteristic curve (ROC) for predicting thrombosis events. Area under the curve (AUC) was 0.898. Maximal sensitivity and specificity (75.4% and 88.5%, respectively) were obtained when SUVmean was 0.882.

Conclusions: Vulnerable and stable plaques can be distinguished by quantitative analysis of (18)F-FDG uptake in the arterial segments in this rabbit model. PET/CT may be used for predicting thrombosis events and risk-stratification in patients with atherosclerotic disease.