Shear Wave Velocity Estimation by Virtual Sensing Array Spectrum Analysis

Abstract

Tissue displacement by continuous shear wave propagation successfully gives local wavelength, which depends on the local velocity of the shear wave. Our goal for velocity distribution estimation in future clinical applications is to achieve less than 10% error and less than 5 mm spatial resolution. However, this has been difficult to achieve owing to the presence of multiple shear waves generated by complicated propagation such as reflection, scattering, and diffraction. In this paper, we propose a velocity estimation method based on wave number spectrum analysis from the limited small area of the displacement distributions. To increase the spatial resolution, we derive a deconvolution-based displacement estimation method for high-frequency excitation. The effectiveness of this method is demonstrated through numerical simulations and experiments with agar phantom. Even if a large reflected wave from a boundary exists, it is found that this method achieved the velocity estimation error of 10% and spatial resolution of 4.5 mm at a wavelength of 2.2 mm.