Department of Electrical and Computer Engineering, University of Rochester, Hopeman Building 203, PO Box 270126, Rochester, NY 14627-0126, United States of America.
Phys Med Biol. 2019 Jan 8;64(2):025008. doi: 10.1088/1361-6560/aaf59a.
Many approaches to elastography incorporate shear waves; in some systems these are produced by acoustic radiation force (ARF) push pulses. Understanding the shape and decay of propagating shear waves in lossy tissues is key to obtaining accurate estimates of tissue properties, and so analytical models have been proposed. In this paper, we reconsider a previous analytical model with the goal of obtaining a computationally straightforward and efficient equation for the propagation of shear waves from a focal push pulse. Next, this model is compared with an experimental optical coherence tomography (OCT) system and with finite element models, in two viscoelastic materials that mimic tissue. We find that the three different cases-analytical model, finite element model, and experimental results-demonstrate reasonable agreement within the subtle differences present in their respective conditions. These results support the use of an efficient form of the Hankel transform for both lossless (elastic) and lossy (viscoelastic) media, and for both short (impulsive) and longer (extended) push pulses that can model a range of experimental conditions.
许多弹性成像方法都采用剪切波；在某些系统中，这些剪切波是由声辐射力（ARF）推脉冲产生的。了解有耗组织中传播剪切波的形状和衰减是获得组织特性准确估计的关键，因此已经提出了分析模型。在本文中，我们重新考虑了以前的分析模型，目的是获得从聚焦推脉冲传播剪切波的计算上简单且高效的方程。接下来，将该模型与实验光学相干断层扫描（OCT）系统和两种模拟组织的粘弹性材料的有限元模型进行了比较。我们发现，三种不同的情况-分析模型，有限元模型和实验结果-在各自条件下的细微差异内表现出合理的一致性。这些结果支持在无损耗（弹性）和有损耗（粘弹性）介质以及短（脉冲）和更长（扩展）推脉冲的情况下都使用高效的汉克尔变换，这些推脉冲可以模拟一系列实验条件。
