Plane Wave Elastography: A Frequency-Domain Ultrasound Shear Wave Elastography Approach

TL;DR

This paper introduces Plane Wave Elastography (PWE), a new ultrasound shear wave elastography method that automatically determines wave directions and reconstructs shear modulus fields using a frequency-domain wave equation, eliminating the need for prior directional filtering.

Contribution

PWE provides a novel, efficient approach to SWE that models wave propagation with plane waves in the frequency domain, improving robustness and accuracy over existing methods.

Findings

Handles complex waveforms without prior filtering

Competitive with state-of-the-art methods

Efficient nonlinear least-squares optimization

Abstract

In this paper, we propose Plane Wave Elastography (PWE), a novel ultrasound shear wave elastography (SWE) approach. Currently, commercial methods for SWE rely on directional filtering based on the prior knowledge of the wave propagation direction, to remove complicated wave patterns formed due to reflection and refraction. The result is a set of decomposed directional waves that are separately analyzed to construct shear modulus fields that are then combined through compounding. Instead, PWE relies on a rigorous representation of the wave propagation using the frequency-domain scalar wave equation to automatically select appropriate propagation directions and simultaneously reconstruct shear modulus fields. Specifically, assuming a homogeneous, isotropic, incompressible, linear-elastic medium, we represent the solution of the wave equation using a linear combination of plane waves propagating in arbitrary directions. Given this closed-form solution, we formulate the SWE problem as a nonlinear least-squares optimization problem which can be solved very efficiently. Through numerous phantom studies, we show that PWE can handle complicated waveforms without prior filtering and is competitive with state-of-the-art that requires prior filtering based on the knowledge of propagation directions.