Combined 18F-FDG PET-CT and DCE-MRI to Assess Inflammation and Microvascularization in Atherosclerotic Plaques

Background and Purpose Hallmarks of vulnerable atherosclerotic plaques are inflammation that can be assessed with (18)fluorine-fluorodeoxyglucose positron emission tomography/computed tomography, and increased neovascularization that can be evaluated by dynamic contrast-enhanced-MRI. It remains unclear whether these parameters are correlated or represent independent imaging parameters. This study determines whether there is a correlation between inflammation and neovascularization in atherosclerotic carotid plaques. Methods A total of 58 patients with transient ischemic attack or minor stroke in the carotid territory and ipsilateral carotid artery stenosis of 30% to 69% were included. All patients underwent positron emission tomography/computed tomography and dynamic contrast-enhanced-MRI of the carotid plaque. (18)Fluorine-fluorodeoxyglucose standard uptake values with target/background ratio were determined. Neovascularization was quantified by the mean (leakage) volume transfer constant K-trans. Spearman rank correlation coefficients between target/background ratio and K-trans were calculated. Results Images suitable for further analysis were obtained in 49 patients. A weak but significant positive correlation between target/background ratio and mean K-trans (Spearman =0.30 [P=0.035]) and 75th percentile K-trans (Spearman =0.29 [P=0.041]) was found. Conclusions There is a weak but significant positive correlation between inflammation on positron emission tomography/computed tomography and neovascularization as assessed with dynamic contrast-enhanced-MRI. Future studies should investigate which imaging modality has the highest predictive value for recurrent stroke, as these are not interchangeable.