Viscoelasticity inversion for arterial shear wave elastography

Abstract

Arterial stiffness, an important biomarker of many cardiovascular diseases, is strongly influenced by the wall modulus. In shear wave elastography, the arterial wall is excited by acoustic radiation force, and the resulting wave propagation characteristics are used to infer arterial stiffness. In earlier ASA meeting, we presented a forward model that returns arterial wall motion for a given geometry, material properties of the waveguide, and input acoustic radiation force. In this work, we propose an inversion approach developed on this forward model to estimate arterial viscoelasticity, which is also considered an important biomarker. Recently, the phase-velocity dispersion is utilized to estimate the arterial wall elastic modulus. However, this approach fails to estimate the viscoelastic modulus since the dispersion curve is not strongly influenced by the arterial wall viscoelasticity. Conversely, the spatiotemporal representation of the wall velocity is sensitive to both moduli. Therefore, in the inverse model, we minimize the mismatch between the measured and simulated particle velocities to invert for the parameters of viscoelasticity, e.g., modulus and damping coefficient for the Voigt model, modulus, and exponent for the Spring-pot model. This talk would contain the details of the underlying formulations and numerical examples illustrating the effectiveness of the proposed approach.