Ex Vivo measurements of myocardial viscoelasticity using Shearwave Dispersion Ultrasound Vibrometry (SDUV)

Stiffening of the left ventricle can compromise the ability of the heart to pump sufficient amounts of blood into the systemic circulation and could lead to heart failure. Quantifying mechanical properties of the left ventricular (LV) myocardium using a noninvasive technique would be of great benefit in clinical settings. We investigated the feasibility of using Shearwave Dispersion Ultrasound Vibrometry (SDUV) to measure viscoelasticity of the myocardium. A mechanical actuator was used to induce shear waves at multiple frequencies (40-500 Hz) in excised LV myocardium and urethane rubber samples, and a pulse echo ultrasound transducer was used to detect the motion at each frequency. An anti-symmetric Lamb wave model was fit to the shear wave dispersion curves in four orthogonal directions to obtain elastic and viscous moduli.