Comparison of Cardiac Displacements in a Murine Model of Myocardial Ischemia using Cardiac Elastography and Speckle Tracking Echocardiography

Investigation of myocardial dynamics through the assessment of mechanical properties of the heart is a challenging problem due to tradeoff between the heart rate and ultrasound frame rate. The objective of this study was to compare displacements estimated using radiofrequency (RF) signals with Cardiac Elastography (CE) and Speckle Tracking Echocardiography (STE) for quantifying myocardial dynamics with B-mode signals. Myocardial dynamics with CE and STE were evaluated using cumulative radial displacements in short-axis views on a left anterior descending (LAD) artery murine ligation model. Cumulative radial displacement estimated in all six segments of the left ventricle was significantly reduced following ligation with both methods. For CE, the global peak radial displacement (GPRD) reduced from 1.28 mm at baseline to 0.55 mm after 14 days and 0.43 mm after 28 days respectively. A similar trend was observed with STE with the corresponding GPRD values ranging from 0.16 mm to 0.15 mm and 0.03 mm respectively. The comparable performance with commercially available software shows the potential of cardiac elastography in studying myocardial dynamics with higher sensitivity due to the phase information present with RF signals.