Simulation of shear wave elastography imaging using the toolbox “k-Wave”

Abstract

Elastography is used to map the local elasticity of tissue. It can detect areas inside the body with a different elasticity from that of surrounding tissue indicative of pathologies like tumours. Shear wave elastography imaging produces an elasticity map by analysing the propagation of shear waves. One source of shear wave is the acoustic radiation force produced by ultrasound. The prediction of the acoustic radiation force and of the shape and amplitude of the ensuing shear displacement is crucial. In this study we present simulations of the radiation force produced by an ultrasound transducer and of the shear displacement it produces using the software package “k-Wave”. Results from simulations in a homogeneous and isotropic medium are compared against analytical solutions and results from a finite element modelling software. The obtained shear displacements from k-Wave are very similar to the analytical solution with a root mean square error around the focal zone below 9% and 21% for short and large propagation times, respectively. k-Wave appears to be an accurate and efficient tool for simulation of acoustic radiation force and shear wave propagation. It combines the simplicity of finite time difference methods with the flexibility to simulate in any heterogeneous medium.