Intravascular optical coherence tomography detection of atherosclerosis and inflammation in Murine aorta

Abstract

Objective-: The goal of this study was to evaluate the feasibility of imaging the aorta of apolipoprotein E-deficient (ApoE -/-) mice for the detection of atherosclerosis and macrophages using optical coherence tomography (OCT) compared with histology. Methods And Results-: Atherosclerosis was induced by high-fat diet in 7-week-old ApoE -/- mice for 10 (n=7) and 22 (n=7) weeks. Nine-week-old ApoE -/- mice (n=7) fed a standard chow diet were used as controls. OCT images of a 10-mm descending aorta in situ were performed in 4 mice for each, and plaque and macrophages were determined at 0.5-mm intervals. Automated detection and quantification of macrophages were performed independently using a customized algorithm. Coregistered histological cross-sections were stained with hematoxylin-eosin, Mac-3, and von Kossa. Three mice in each group had en face OCT imaging to detect macrophages, which were compared with lipid-positive area with Sudan IV. OCT images were successfully acquired in all mice. OCT and histology were able to discriminate macrophages and plaque among the 3 groups and showed excellent correlation for (1) visual detection of plaque (r=0.98) and macrophages (r=0.93), (2) automated detection and quantification of macrophages by OCT versus Mac-3-positive area (r=0.92), and (3) en face OCT detection of macrophages versus Sudan IV-positive area (r=0.92). Conclusion-: Murine intra-aortic OCT is feasible and shows excellent correlation with histology for detection of atherosclerotic plaque and macrophages. © 2012 American Heart Association, Inc.