Abstract 20912: Coronary Artery Plaques with High-risk Morphological Features Display an Increased Inflammatory Activity as Demonstrated by PET-CT Imaging
Background: Vascular 18F-Fluorodeoxyglucose (FDG) activity, detected by Positron Emission Tomography (PET) correlates with atherosclerotic inflammation. Here we test the hypothesis that inflammation (measured by FDG-PET) is increased in coronary artery plaques with High Risk Morphological features (HRM) as defined by coronary CT angiography (CTA).
Methods: Nineteen patients with stable atherosclerotic disease underwent FDG-PET and CTA imaging. Left main coronary artery (LM) was assessed for presence and morphology of atherosclerotic plaque using CTA imaging. A 10 mm segment adjacent to the LM bifurcation was analyzed. Plaque with HRM was defined by low CT attenuation (<50 HU) and/or presence of spotty calcification. FDG uptake was measured within the center of the LM while blinded to CTA analysis. Target-to-background ratio (TBR) was calculated by dividing the LM by blood activity. TBR of the LM was then compared to the underlying plaque morphology.
Results: LM plaques were present on CTA in 14 patients, of which 9 contained HRM. TBR was increased in LM containing plaques with HRM (median [interquartile range]: 1.9 [1.67, 2.33] vs. 1.37 [1.25, 1.56], p=0.004). Conversely, the presence of heavy LM calcification was associated with a lower FDG signal (1.38 [1.31, 1.81] vs. 1.90 [1.61, 2.34], p< 0.03).
Conclusions: This study demonstrates increased inflammatory activity within LM plaques with HRM (plaque hypodensity or spotty calcification) and also suggests that plaque inflammation is reduced in heavily calcified coronary segments. These findings prove the feasibility of structural and functional assessment of coronary plaques using FDG-PET and CTA.
- © 2010 by American Heart Association, Inc.