Attenuation of an Ultrasound Contrast Agent Estimated from Transient Solution of Linearized Rayleigh-Plesset Equation

TL;DR

This paper develops a transient solution-based model for estimating ultrasound contrast agent attenuation, addressing limitations of steady-state assumptions and improving accuracy in characterizing microbubble behavior.

Contribution

It introduces a formula that accounts for transient oscillations in the Rayleigh-Plesset equation, enhancing the modeling of UCA shell parameters.

Findings

Transient oscillations significantly affect attenuation estimates.

The proposed model improves agreement with experimental data.

Steady-state assumptions may lead to inaccuracies in UCA characterization.

Abstract

The attenuation of low-intensity acoustic waves in the suspension of ultrasound contrast agents (UCAs, microbubbles) is determined by the oscillation of the microbubbles in the medium. This bubble-induced attenuation is a linear phenomenon and can be estimated via a linearized Rayleigh-Plesset equation (RPE). In the material characterization, theoretical attenuation is estimated from steady state oscillation of an UCA and immediately compared with experimental attenuation data that are usually measured by shot-pulse ultrasound. However, discrepancy could exist in the characterization if the UCA does not ring up to steady state oscillation. In this article, we investigate the situation where the transient solution of the RPE is not negligible and discuss its impact on the modeling of the shell parameters of an UCA. We provide a formula for attenuation estimation considering the contribution due to transient oscillation.