Visualization and Characterization of Atherosclerotic Plaques by Micro-MRI at 4.7 T In Vivo and 11.7 T Ex Vivo

The aim of this study was to evaluate the capability of using micro-magnetic resonance imaging (MRI) to visualize and characterize atherosclerotic plaques of mouse models. Twenty five apolipoprotein E-knockout mice were fed atherogenic diet, which enabled creation of aortic atherosclerotic plaques. Aortic plaques were examined in vivo by 4.7 T MRI and then characterized ex vivo by 11.7 T three-dimensional MRI. MR images were correlated with subsequent histological confirmation. In vivo 4.7-T MRI demonstrated unevenly thickened aortic walls due to formation of atherosclerotic plaques. Ex vivo 11.7-T MRI enabled not only to acquire full volume-rendered images of the entire vessels but also to characterize plaque components (such as lipid cores and fibrous caps) at any level and any projection, which were confirmed by histological correlation. Micro-MRI provides an excellent imaging tool for basic science to investigate atherosclerosis in small animal models, which may become a supplement to histopathology of atherosclerotic cardiovascular disease.