Feasibility of in vivo 18F-florbetaben PET/MR imaging of human carotid amyloid-β

Abstract

Purpose: Amyloid-beta (Aβ) peptides are involved in the inflammatory pathology of atherosclerosis. 18F-Florbetaben is a PET tracer for clinical imaging of cerebral Aβ plaques in Alzheimer’s disease (AD). We sought to determine whether specific uptake of 18F-florbetaben in the carotid arteries can be identified using a fully integrated hybrid PET/MRI system and whether this uptake is associated with clinical cardiovascular disease (CVD) risk factors. Methods: Carotid 18F-florbetaben uptake was quantified as the mean of the maximum target-to-background ratio (meanTBRmax) in 40 cognitively impaired subjects (age 68.2 ± 9.5 years) undergoing 18F-florbetaben PET/MRI to diagnose AD. Associations between carotid 18F-florbetaben uptake and several CVD risk factors were assessed by univariate analysis followed by a multivariate linear regression analysis. Furthermore, carotid 18F-florbetaben uptake was compared between patients with and without a positive cerebral Aβ PET scan. Results: 18F-Florbetaben uptake was clearly visualized in the carotid arteries. Values of meanTBRmax corrected for the blood pool activity of the tracer showed specific 18F-florbetaben uptake in the carotid wall. Male gender was associated with carotid 18F-florbetaben uptake in the univariate analysis, and was found to be an independent predictor of 18F-florbetaben uptake in the multivariate regression analysis (standardized regression coefficient β = 0.407, p = 0.009). Carotid 18F-florbetaben meanTBRmax in patients with a positive cerebral Aβ scan did not differ from that in patients without cerebral Aβ deposits. Conclusion: Specific 18F-florbetaben uptake in human carotid arteries was detected. Male gender was identified as an independent clinical risk factor. Therefore, 18F-florbetaben PET/MRI might provide new insights into the pathophysiological process in atherosclerosis.