Abstract 14321: A Validation Study of Myocardial Elastography Against Coronary Computed Tomography Angiography in Patients with Coronary Artery Disease

Introduction: Myocardial Elastography (ME) is a new quantitative strain imaging method capable of detecting ischemia due to Coronary Artery Disease (CAD). ME has been compared to nuclear perfusion imaging with good agreement. Coronary Computed Tomography Angiography (CCTA) has been shown to have superior accuracy to nuclear perfusion imaging for CAD staging. In this study, ME is compared to CCTA in CAD patients. Methods: High framerate (300 fps) echocardiography in five patients presented with chest pain or shortness of breath symptoms, or having prior history of CAD. Standard short-axis views were acquired at the mid-, basal, and apical left-ventricular (LV) levels using a research ultrasound system (Vantage, Verasonics) with a phased array (P4-2, Philips). ME radial systolic strain (ε) was imaged to evaluate wall thickening using 2D cross-correlation and gradient-based methods on the raw (RF) signals. Average ε within each perfusion territory (LAD, RCA, LCX) was then computed N=45. CCTA was performed using an AcquilionOne Scanner (Canon) with Iohexol (Omnipaque, GE) for contrast. Echocardiograms were coregistered with CCTA using anatomical landmarks. Results: Good qualitative agreement between ε (ME) and stenosis level (CCTA) was obtained (Fig. 1A). ME was sensitive in detecting moderate to severe stenosis showing reduced ε. At mild stenosis, despite a trend of ε reduction, some territories maintained mechanical functionality, possibly due to collateral engagement, demonstrating that both structural (CCTA) and functional (ME) properties are complementary in informing on myocardial viability and functionality, especially at mild stenosis. Future work will entail incorporation of FFR CT measurements as an additional functional reference measurement to validate ME strain.