Asemani Hamidreza, Rolland Jannick P, Parker Kevin J
IEEE Trans Biomed Eng. 2025 Feb;72(2):586-594. doi: 10.1109/TBME.2024.3464104. Epub 2025 Jan 21.
In shear wave elastography (SWE), the aim is to measure the velocity of shear waves, however unwanted compression waves and bulk tissue motion pose challenges in evaluating tissue stiffness. Conventional approaches often struggle to discriminate between shear and compression waves, leading to inaccurate shear wave speed (SWS) estimation. In this study, we propose a novel approach known as the integrated difference autocorrelation (IDA) estimator to accurately estimate reverberant SWS in the presence of compression waves and noise.
The IDA estimator, unlike conventional techniques, computes the subtraction of velocity between neighboring particles, effectively minimizing the impact of long wavelength compression waves and other wide-area movements such as those caused by respiration. We evaluated the effectiveness of IDA by: (1) using k-Wave simulations of a branching cylinder in a soft background, (2) using ultrasound elastography on a breast phantom, (3) using ultrasound elastography in the human liver-kidney region, and (4) using magnetic resonance elastography (MRE) on a brain phantom.
By applying IDA to unfiltered contaminated wave fields of simulation and elastography experiments, the estimated SWSs are in good agreement with the ground truth values (i.e., less than 2% error for the simulation, 9% error for ultrasound elastography of the breast phantom and 19% error for MRE).
Our results demonstrate that IDA accurately estimates SWS, revealing the existence of a lesion, even in the presence of strong compression waves.
IDA exhibits consistency in SWS estimation across different modalities and excitation scenarios, highlighting its robustness and potential clinical utility.
在剪切波弹性成像（SWE）中，目标是测量剪切波的速度，然而，不需要的压缩波和组织整体运动在评估组织硬度时带来了挑战。传统方法往往难以区分剪切波和压缩波，导致剪切波速度（SWS）估计不准确。在本研究中，我们提出了一种新的方法，称为积分差分自相关（IDA）估计器，以在存在压缩波和噪声的情况下准确估计混响SWS。
与传统技术不同，IDA估计器计算相邻粒子之间的速度差，有效最小化长波长压缩波和其他大面积运动（如呼吸引起的运动）的影响。我们通过以下方式评估IDA的有效性：（1）使用在软背景中的分支圆柱体的k-Wave模拟，（2）在乳腺模型上使用超声弹性成像，（3）在人体肝肾区域使用超声弹性成像，以及（4）在脑模型上使用磁共振弹性成像（MRE）。
通过将IDA应用于模拟和弹性成像实验的未滤波污染波场，估计的SWS与真实值高度一致（即模拟误差小于2%，乳腺模型超声弹性成像误差为9%，MRE误差为19%）。
我们的结果表明，IDA即使在存在强压缩波的情况下也能准确估计SWS，揭示病变的存在。
IDA在不同模态和激发场景下的SWS估计中表现出一致性，突出了其稳健性和潜在的临床应用价值。
