Numerical Modeling of Ultrasound Propagation in Weakly Heterogeneous Media Using a Mixed-Domain Method.
Numerical Modeling of Ultrasound Propagation in Weakly Heterogeneous Media Using a Mixed-Domain Method.
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DOI：
10.1109/tuffc.2018.2828316
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发表时间：
2018-07
期刊：
影响因子：
--
通讯作者：
Jing Y
中科院分区：
文献类型：
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作者：
Gu J;Jing Y
针对声速、密度、衰减系数和非线性系数均为空间变化函数的任意非均匀生物组织中的单向线性/非线性波传播问题，提出了一种混合域法(MDM)。本方法是基于求解由类Westvelt方程导出的积分方程解的。首先研究了一维问题，以验证MDM并揭示其局限性。结果表明，对于声速变化较小的情况，该方法具有较高的精度。为了验证该方法在医学领域的应用，进一步研究了聚焦超声波束在二维情况下的应用。计算结果采用了MatLab工具箱k-Wave作为基准。当采用最粗网格(波长的1/3)时，换能器焦点处的归一化均方根误差估计为0.0133。对所考虑的计算域中的基频和二次谐场进行了比较，并观察到了良好的一致性。总体而言，这项研究表明，当用MDM来模拟非均质性相对较弱的生物组织中的波传播时，MDM是一种计算高效和准确的方法。
A mixed domain method (MDM) is presented in this paper for modeling one-way linear/nonlinear wave propagation in biological tissue with arbitrary heterogeneities, in which sound speed, density, attenuation coefficients and nonlinear coefficients are all spatial varying functions. The present method is based on solving an integral equation derived from a Westervelt-like equation. One-dimensional problems are first studied to verify the MDM and to reveal its limitations. It is shown that this method is accurate for cases with small variation of sound speed. A two-dimensional case is further studied with focused ultrasound beams to validate the application of the method in the medical field. Results from the MATLAB toolbox k-Wave are used as the benchmark. Normalized root-mean-square (RMS) error estimated at the focus of the transducer is 0.0133 when the coarsest mesh (1/3 of the wavelength) is used in the MDM. Fundamental and second-harmonic fields throughout the considered computational domains are compared and good agreement is observed. In overall, this study demonstrates that the MDM is a computationally efficient and accurate method when used to model wave propagation in biological tissue with relatively weak heterogeneities.