Inversion of Lamb waves in Shearwave Dispersion Ultrasound Vibrometry (SDUV)

Close to half of the heart failures are due to diastolic dysfunction which is accompanied by stiffening of the left-ventricular myocardium. Our group has recently proposed the use of Shearwave Dispersion Ultrasound Vibrometry (SDUV) to excite and track Lamb waves to quantify viscoelasticity of the myocardium. SDUV measures dispersion velocities using the phase gradient method which assumes presence of a single wave mode and absence of wave reflections. Direct inversion is a method for estimating wave velocity and attenuation that only requires the displacement versus time signal and is therefore more robust. In this study, we compare the results of measuring Lamb wave velocity and attenuation using the phase gradient and amplitude decay, and the direct inversion.