Eigen-vibration model of an ellipsoidal shell for ultrasonic estimation of left-ventricular myocardial elasticity

Left-ventricular myocardial elasticity was ultrasonically estimated by using an eigen-vibration model of an ellipsoidal shell, namely an extension of the spherical-shell model developed by Advani and Lee (1970). The model simplifies the complex shell dynamics based on the underlining assumption that the non-dimensional eigenfrequency only depends on the shape of the shell and is independent of its physical scale or properties. As for the ellipsoidal-shell model, it is simply considered that ellipticity describes eigenfrequency-shifts from spherical shells to ellipsoidal shells. A finite-element method (FEM) verified the assumption used in the model. An eigenfrequency-shift comparison of the ellipsoidal-shell model and experimental measurements by using silicon shells reasonably validated the model.