Wang Yu, Peng Bo, Jiang Jingfeng
Department of Biomedical Engineering, College of Engineering, Michigan Technological University, Houghton, Michigan, United States of America.
Phys Med Biol. 2017 Mar 7;62(5):1949-1968. doi: 10.1088/1361-6560/aa58c9. Epub 2017 Jan 11.
Ultrasound-based elastography including strain elastography, acoustic radiation force impulse (ARFI) imaging, point shear wave elastography and supersonic shear imaging (SSI) have been used to differentiate breast tumors among other clinical applications. The objective of this study is to extend a previously published virtual simulation platform built for ultrasound quasi-static breast elastography toward acoustic radiation force-based breast elastography. Consequently, the extended virtual breast elastography simulation platform can be used to validate image pixels with known underlying soft tissue properties (i.e. 'ground truth') in complex, heterogeneous media, enhancing confidence in elastographic image interpretations. The proposed virtual breast elastography system inherited four key components from the previously published virtual simulation platform: an ultrasound simulator (Field II), a mesh generator (Tetgen), a finite element solver (FEBio) and a visualization and data processing package (VTK). Using a simple message passing mechanism, functionalities have now been extended to acoustic radiation force-based elastography simulations. Examples involving three different numerical breast models with increasing complexity-one uniform model, one simple inclusion model and one virtual complex breast model derived from magnetic resonance imaging data, were used to demonstrate capabilities of this extended virtual platform. Overall, simulation results were compared with the published results. In the uniform model, the estimated shear wave speed (SWS) values were within 4% compared to the predetermined SWS values. In the simple inclusion and the complex breast models, SWS values of all hard inclusions in soft backgrounds were slightly underestimated, similar to what has been reported. The elastic contrast values and visual observation show that ARFI images have higher spatial resolution, while SSI images can provide higher inclusion-to-background contrast. In summary, our initial results were consistent with our expectations and what have been reported in the literature. The proposed (open-source) simulation platform can serve as a single gateway to perform many elastographic simulations in a transparent manner, thereby promoting collaborative developments.
基于超声的弹性成像技术，包括应变弹性成像、声辐射力脉冲（ARFI）成像、点剪切波弹性成像和超音速剪切成像（SSI），已被用于鉴别乳腺肿瘤以及其他临床应用。本研究的目的是将先前发布的用于超声准静态乳腺弹性成像的虚拟仿真平台扩展到基于声辐射力的乳腺弹性成像。因此，扩展后的虚拟乳腺弹性成像仿真平台可用于在复杂、异质介质中验证具有已知潜在软组织特性（即“真实情况”）的图像像素，增强对弹性成像图像解释的信心。所提出的虚拟乳腺弹性成像系统继承了先前发布的虚拟仿真平台的四个关键组件：超声模拟器（Field II）、网格生成器（Tetgen）、有限元求解器（FEBio）和可视化与数据处理包（VTK）。通过使用简单的消息传递机制，功能现已扩展到基于声辐射力的弹性成像模拟。涉及三个不同复杂度不断增加的数值乳腺模型的示例——一个均匀模型、一个简单包含模型和一个从磁共振成像数据导出的虚拟复杂乳腺模型，用于展示这个扩展虚拟平台的能力。总体而言，将模拟结果与已发表的结果进行了比较。在均匀模型中，估计的剪切波速度（SWS）值与预定的SWS值相比在4%以内。在简单包含模型和复杂乳腺模型中，软背景中所有硬包含物的SWS值略有低估，与已报道的情况类似。弹性对比度值和视觉观察表明，ARFI图像具有更高的空间分辨率，而SSI图像可以提供更高的包含物与背景对比度。总之，我们的初步结果与我们的预期以及文献中报道的结果一致。所提出的（开源）仿真平台可以作为一个单一的通道，以透明的方式执行许多弹性成像模拟，从而促进协作开发。
