Abstract 8229: Layer Specific Strain-Encoded Magnetic Resonance Imaging for Evaluation of Left Ventricular Function and Infarct Transmurality in Patients With Chronic Coronary Artery Disease

Abstract

Background: Strain-encoded imaging (SENC) is a new technique for myocardial deformation analysis in cardiac magnetic resonance imaging (MRI). The study aimed to evaluate whether myocardial deformation imaging performed by SENC allows quantification of regional left ventricular (LV) function and is related to scar transmurality defined by contrast-enhanced MRI (ceMRI). Methods: 50 patients (age 62 ± 10 years) with chronic ischemic LV dysfunction underwent ceMRI using a clinical 1.5T scanner (Achieva, Philips, Best, The Netherlands). Strain-encoded images were acquired using a commercially available software to calculate myocardial endocardial and epicardial strain (Diagnosoft SENC version 2.05, Diagnosoft Inc., Palo Alto, USA). Layer-specific peak circumferential strain was measured from long-axis views and peak longitudinal strain was evaluated from short-axis views in a 16-segment model. The extent of myocardial infarction was determined semiautomatically (CAAS MRV 3.3, Pie Medical, Netherlands) for each segment as relative amount of hyperenhancement by ceMRI (0%: no infarction; 1-50%: non-transmural infarction; 51-100%: transmural infarction). Results: A total of 589 of 600 segments (98%) were analyzed. Endocardial and epicardial circumferential as well as longitudinal strain showed significant differences between visually defined segmental function states and differed also significantly between the degree of infarct transmurality (all p<0.001). A cutoff peak circumferential endocardial strain value of -15% differentiated nontransmural from transmural infarcted myocardium with a sensitivity of 100% and a specificity of 86% (area under the curve (AUC) 0.94). Distinction of nontransmural infarcted myocardium from transmural infarcted myocardium was done more accurately using circumferential endocardial strain compared to longitudinal endocardial strain (AUC 0.94 vs. AUC 0.76, p=0.003). Conclusions: Layer-specific SENC provides objective quantification of regional myocardial function and allows accurate discrimination between different transmurality states of myocardial infarction. Circumferential endocardial strain showed the best distinction between the different degrees of infarct transmurality.