Numerical simulation of impulse-induced surface acoustic waves for elastography purposes using k-Wave simulation toolbox

Abstract

As elastography, an emerging medical imaging strategy, advances, surface acoustic waves have been utilized to examine superficial tissues quantitatively. So far, most studies are experimental, and a numerical method is needed to cost-effectively investigate surface acoustic wave generation and propagation for technical development and optimization purposes. This study aims to develop a reliable numerical method for simulating impulse-induced surface acoustic waves using the k-wave simulation toolbox. According to the physical process of surface acoustic wave based elastography, the proposed simulation method consists of two stages: compressional wave simulation and elastic wave simulation, which aim to generate acoustic radiation force impulse and elastic waves, respectively. The technical procedures were demonstrated by a wave simulation on a water–tissue model. Meanwhile, three acoustic radiation force modeling methods were adopted. The compressional wave simulation showed that the three force modeling methods could produce similar force distribution in space but largely different amplitudes. The elastic wave simulation confirmed the feasibility of numerically generating surface acoustic waves. The reliability of the simulated waves was verified by a quantitative comparison between the numerically acquired sound speeds and their theoretical expectations and by a qualitative comparison between the numerically generated waves and the experimental observations under similar conditions. In summary, this study confirms k-wave as an effective numerical method for simulating surface acoustic waves for elastography purposes. This study provides an immediate simulation platform for investigating Scholte waves, the surface acoustic wave at a liquid–solid interface, and also, a potential numerical framework to investigate other surface acoustic waves.