基于爬行波数据的声弹性成像中剪切波速的恢复。
Shear wave speed recovery in sonoelastography using crawling wave data.
机构信息
Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
出版信息
J Acoust Soc Am. 2010 Jul;128(1):88-97. doi: 10.1121/1.3442575.
The crawling wave experiment, in which two harmonic sources oscillate at different but nearby frequencies, is a development in sonoelastography that allows real-time imaging of propagating shear wave interference patterns. Previously the crawling wave speed was recovered and used as an indicator of shear stiffness; however, it is shown in this paper that the crawling wave speed image can have artifacts that do not represent a change in stiffness. In this paper, the locations and shapes of some of the artifacts are exhibited. In addition, a differential equation is established that enables imaging of the shear wave speed, which is a quantity strongly correlated with shear stiffness change. The full algorithm is as follows: (1) extract the crawling wave phase from the spectral variance data; (2) calculate the crawling wave phase wave speed; (3) solve a first-order PDE for the phase of the wave emanating from one of the sources; and (4) compute and image the shear wave speed on a grid in the image plane.
爬行波实验是超声弹性成像中的一种发展，它利用两个不同但邻近频率的谐波源进行震荡，从而实时显示传播的剪切波干涉模式。此前，爬行波速度被恢复并用作剪切刚度的指标；然而，本文表明，爬行波速度图像可能存在伪影，这些伪影并不代表刚度的变化。本文展示了一些伪影的位置和形状。此外，还建立了一个微分方程，可以对剪切波速度进行成像，剪切波速度与剪切刚度的变化密切相关。完整的算法如下：（1）从频谱方差数据中提取爬行波相位；（2）计算爬行波相位的波速；（3）求解源于其中一个源的波的相位的一阶偏微分方程；（4）在图像平面上的网格中计算和显示剪切波速度。
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