A particle-based simulation tool for ultrasound blood flow imaging: Validation of high-speed Echo-PIV

This work aims to study the potential of high-speed echographic particle image velocimetry (Echo-PIV) technique based on plane wave excitation in physiological flows. We evaluate the Echo-PIV technique using a simulation environment integrating smoothed particle hydrodynamics (SPH), a mesh-free method in computational mechanics, and linear acoustics. In SPH, the fluid domain is divided into a set of particles and the physical properties of each particle are calculated based on the properties of the neighboring particles. By contrast with standard computational methods, fluid-acoustic coupling is effortless since SPH particles can be used directly as sound scatterers. Field II is used as a scattering acoustic model. SPH particles are insonified with ultrasound plane waves and the backscattered RF signals are analyzed. The Poiseuille and Womersley flows, as standard benchmark cases, and then pulsatile flow in a bifurcation artery are insonified perpendicularly by acoustic plane waves at a rate higher than 1000 fps. The velocity fields are then determined using iterative multigrid PIV processing on the RF images. The velocity profiles derived by high-speed Echo-PIV were very concordant with those yielded by SPH.