IEEE Trans Ultrason Ferroelectr Freq Control. 2019 Sep;66(9):1444-1452. doi: 10.1109/TUFFC.2019.2923710. Epub 2019 Jun 20.
The elastic properties of human tissue can be evaluated through the study of mechanical wave propagation captured using high frame rate ultrasound imaging. Methods such as block-matching or phase-based motion estimation have been used to estimate the displacement induced by the mechanical waves. In this paper, a new method for detecting mechanical wave propagation without motion estimation is presented, where the motion of interest is accentuated by an appropriate clutter filter. Thus, the mechanical wave propagation will directly appear as bands of the attenuated signal moving in the B-mode sequence and corresponding anatomical M-mode images. While only the locality of tissue velocity induced by the mechanical wave is detected, it is shown that the method is more sensitive to subtle tissue displacements when compared to motion estimation techniques. The technique was evaluated for the propagation of the pulse wave in a carotid artery, mechanical waves on the left ventricle, and shear waves induced by radiation force on a tissue-mimicking phantom. The results were compared to tissue Doppler imaging (TDI) and demonstrated that clutter filter wave imaging (CFWI) was able to detect the mechanical wave propagating in tissue with a relative temporal and spatial resolution 30% higher and a relative consistency 40% higher than TDI. The results showed that CFWI was able to detect mechanical waves with a relative frequency content 40% higher than TDI in a shear wave imaging experiment.
人体组织的弹性特性可以通过研究使用高帧率超声成像捕获的机械波传播来评估。已经使用诸如块匹配或基于相位的运动估计之类的方法来估计机械波引起的位移。在本文中，提出了一种无需运动估计即可检测机械波传播的新方法，其中通过适当的杂波滤波器突出感兴趣的运动。因此，机械波传播将直接显示为衰减信号的带在 B 模式序列中移动，并对应于相应的解剖 M 模式图像。虽然仅检测到机械波引起的组织速度的局部性，但与运动估计技术相比，该方法对细微的组织位移更敏感。该技术针对颈动脉中的脉冲波传播、左心室中的机械波以及组织模拟体模上的辐射力引起的剪切波进行了评估。结果与组织多普勒成像（TDI）进行了比较，并证明杂波滤波器波成像（CFWI）能够以比 TDI 高 30％的相对时间和空间分辨率以及高 40％的相对一致性来检测在组织中传播的机械波。结果表明，在剪切波成像实验中，CFWI 能够以比 TDI 高 40％的相对频率内容来检测机械波。
