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 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. Fluorine-fluorodeoxyglucose standard uptake values with target/background ratio were determined. Neovascularization was quantified by the mean (leakage) volume transfer constant K. Spearman rank correlation coefficients between target/background ratio and K 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 (Spearman ρ=0.30 [P=0.035]) and 75th percentile K (Spearman ρ=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. CLINICAL TRIAL REGISTRATION—URLhttp://www.clinicaltrials.gov. Unique identifierNCT00451529.