Abstract
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Objectives: To investigate morphological and biological features of vulnerable carotid atherosclerotic plaques in patients with known increased risk of atherosclerosis with hybrid 18F-FDG PET/MR imaging.
Methods: Sixteen patients with known increased risk of atherosclerosis underwent hybrid PET/MR of the carotid arteries after injection of 18F-FDG. PET/MR was performed a median of 130 min after injection. American Heart Association (AHA) lesion type and plaque composition were determined on consecutive MRI axial sections in both carotid arteries. 18F-FDG uptake in carotid arteries was quantified using maximum standardized uptake values (SUVmax) and tissue to background ratio (TBR) on corresponding PET sections.
Results: The prevalence of complicated atherosclerotic plaques (AHA lesion type VI) detected with high-resolution MRI was significantly higher in the carotid artery ipsilateral to the ischemic stroke as compared to the contralateral side (31 vs 0 %; p=0.006). Atherosclerotic plaques classified as vulnerable with MRI (AHA lesion type VI) were associated with higher 18F-FDG uptake in comparison with other AHA lesions (SUVmax=3.31±1.13 vs 1.61±0.68 and 0.91±0.37; TBR=3.21±1.04 vs 1.56±0.53 and 0.88±0.26, respectively; p<0.001).
Conclusions: Morphological and biological features of vulnerable plaques can be detected with 18F-FDG PET/MRI in patients with known increased risk of atherosclerosis. Hybrid 18F-FDG PET/MRI systems might help in the evaluation of patients with vulnerable carotid atherosclerotic plaques. Key words: Atherosclerosis, Vulnerable plaque, Carotid arteries, Positron emission tomography, Magnetic resonance imaging, PET/MR, 18F-FDG