Abstract 16545: Histological Tissue Characterization Of Coronary High Intensity Plaques On Non-contrast T1 Weighted Magnetic Resonance Imaging In Patients With Cardiovascular Diseases: An Ex-vivo Study

Introduction:Recent studies have shown the clinical significance of coronary high intensity plaques (HIPs) detected on T1-weighted magnetic resonance imaging (T1WI) to predict future coronary events in coronary artery disease. Systemic analysis for tissue characterization of coronary HIPs on T1WI still remains scared.Methods:Between March 2014 and July 2017, 25 cadavers (mean age: 78 ? 18.2 years), who died of cardiovascular diseases in our hospital, underwent ex-vivo3-Tesla T1WI within 72 hours after autopsy (MAGNETOM Verio; Siemens AG Healthcare Sector, Erlangen, Germany) and histological transverse sections of coronary arteries corresponding their T1WI sections were co-registered. Qualitative analysis of coronary plaques was defined as the ratio of signal intensity of coronary plaque divided by that of myocardium (PMR). Followingquantitative analysis, coronary HIPs, intermediate intensity plaques (IM-IPs), non-HIPs were defined as plaques with extremely, moderately, or same or lower signal intensity compared with myocardium on T1WI, respectively. Coronary histological sections stained with hematoxylin-eosin staining were categorized by modified AHA classification.Results:Of 1472 sections from 25 cadavers, 105 coronary sections on T1WI were coronary HIPs (median PMR, 1.87; Interquartile range [IQR], 1.70-2.14), 217 sections were IM-IPs (1.30; IQR, 1.15-1.44), and 1150 sections were non-HIPs (1.05; IQR, 0.93-1.2). Fibrous cap atheroma and chronic total occlusion based on modified AHA classification, as well as intraplaque hemorrhage or thrombus, were frequently observed in HIPs compared with IM-IPs or non-HIPs (P<0.001). Conversely, fibrocalcific lesions, pathological intimal thickening and non-atherosclerotic intimal lesions were frequently observed in non-HIP lesions compared with HIPs and IM-IPs (P<0.001). From CART analysis, larger necrotic core area, plaque characteristics with fibrous cap atheroma or chronic total occlusion, and larger plaque area were significant determinants for higher signal intensity of coronary plaques on T1WI.Conclusions:Coronary HIPs on T1WI represent advanced atherosclerosis with larger plaque volume and necrotic core.