Zhu Chi, Seo Jung-Hee, Bakhshaee Hani, Mittal Rajat
Department of Mechanical Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 e-mail:
Professor Department of Mechanical Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 e-mail:
J Biomech Eng. 2017 May 1;139(5). doi: 10.1115/1.4036262.
A computational framework consisting of a one-way coupled hemodynamic-acoustic method and a wave-decomposition based postprocessing approach is developed to investigate the biomechanics of arterial bruits. This framework is then applied for studying the effect of the shear wave on the generation and propagation of bruits from a modeled stenosed artery. The blood flow in the artery is solved by an immersed boundary method (IBM) based incompressible flow solver. The sound generation and propagation in the blood volume are modeled by the linearized perturbed compressible equations, while the sound propagation through the surrounding tissue is modeled by the linear elastic wave equation. A decomposition method is employed to separate the acoustic signal into a compression/longitudinal component (curl free) and a shear/transverse component (divergence free), and the sound signals from cases with and without the shear modulus are monitored on the epidermal surface and are analyzed to reveal the influence of the shear wave. The results show that the compression wave dominates the detected sound signal in the immediate vicinity of the stenosis, whereas the shear wave has more influence on surface signals further downstream of the stenosis. The implications of these results on cardiac auscultation are discussed.
开发了一种由单向耦合血流动力学-声学方法和基于波分解的后处理方法组成的计算框架，以研究动脉杂音的生物力学。然后将该框架应用于研究剪切波对模拟狭窄动脉中杂音产生和传播的影响。动脉中的血流由基于浸入边界法（IBM）的不可压缩流求解器求解。血液体积中的声音产生和传播由线性化扰动可压缩方程建模，而声音通过周围组织的传播由线性弹性波方程建模。采用一种分解方法将声学信号分离为压缩/纵向分量（无旋）和剪切/横向分量（无散），并在表皮表面监测有无剪切模量情况下的声音信号，并进行分析以揭示剪切波的影响。结果表明，压缩波在狭窄紧邻区域主导检测到的声音信号，而剪切波对狭窄下游更远的表面信号有更大影响。讨论了这些结果对心脏听诊的意义。
