Varying Correlation Between 18 F-Fluorodeoxyglucose Positron Emission Tomography and Dynamic Contrast-Enhanced MRI in Carotid Atherosclerosis

Background and Purpose—18F-fluorodeoxyglucose positron emission tomography and dynamic contrast-enhanced MRI have been proposed to quantitatively assess plaque inflammation by probing macrophages and neovessels, respectively. We examined their correlation to study the in vivo relationship between macrophage and neovessel activities in atherogenesis. Methods—Forty-one patients (34 men; aged 65±12 years) with a total of 68 carotid plaques (thickness ≥2 mm on ultrasound; 20 symptomatic) were assessed by both 18F-fluorodeoxyglucose positron emission tomography/computed tomography and dynamic contrast-enhanced MRI within 2 weeks, measured as target-to-background ratio and transfer constant (Ktrans), respectively. Results—Overall, the correlation between target-to-background ratio and Ktrans was weak and marginal (r=0.22; P=0.068). They were correlated in the symptomatic plaques (r=0.59; P=0.006) but not in the asymptomatic plaques (r=0.07; P=0.625; P=0.033 for difference in r). Neither target-to-background rat...