Effect of acoustic streaming on tissue heating due to high-intensity focused ultrasound

TL;DR

This study models how acoustic streaming and blood flow influence tissue heating during HIFU liver tumor ablation, revealing significant effects on temperature distribution and necrosis volume, especially near blood vessels.

Contribution

It introduces a comprehensive 3D acoustics-thermal-fluid model that incorporates acoustic streaming effects into HIFU tissue heating simulations.

Findings

Acoustic streaming significantly alters temperature near blood vessels.

Including streaming effects reduces predicted necrosis volume by about 30%.

Large blood vessels impact temperature distribution due to convection and streaming.

Abstract

The influences of blood vessels and focused location on temperature distribution during high-intensity focused ultrasound (HIFU) ablation of liver tumors is studied. A three-dimensional acoustics-thermal-fluid coupling model is employed to compute the temperature field in the hepatic cancerous region. The model is based on the linear Westervelt and bioheat equations as well as the nonlinear Navier-Stokes equations for the liver parenchyma and blood vessels. The effect of acoustic streaming is also taken into account in the present HIFU simulation study. Different blood vessel diameters and focal point locations were investigated. We found from this three-dimensional numerical study that in large blood vessels both the convective cooling and acoustic streaming can change considerably the temperature field and the thermal lesion near blood vessels. If the blood vessel is located within the beam width, both acoustic streaming and blood flow cooling effects should be taken into account. The predicted temperature difference for the cases considered with and without acoustic streaming effect is 54 % in regions close to the vessel wall. The necrosed volume can be reduced about 30 %, when taking into account acoustic streaming effect.