Institute of Innovative Research, Tokyo Institute of Technology, 4259 R2-25, Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa, 226-8503, Japan.
Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu-shi, Gunma, 376-8515, Japan.
J Med Ultrason (2001). 2024 Jul;51(3):407-418. doi: 10.1007/s10396-024-01439-7. Epub 2024 Apr 12.
Continuous shear wave elastography (C-SWE) can be expected to be applied to portable muscle elasticity diagnosis. To establish diagnostic technology, it will be necessary to improve measurement techniques and quantitative measurement accuracy.
In this study, we investigated two screen scores: the quality index (Q-index), which determines whether the intensity of a power Doppler image is appropriate, and the shear wave propagation direction index (SWDI), which determines the uniformity of shear wave propagation.
First, we performed numerical simulations with white noise and found that the coefficient of variation of shear wave velocity estimation was less than 5% when the normalized Q-index was greater than 0.27. Furthermore, regarding the SWDI, we clarified the relationship between the standard deviation in shear wave propagation direction and the SWDI. Next, the relationship between the Q-index and coefficient of variation of estimated shear wave velocity was evaluated through experiments using a tissue-mimicking phantom. The results showed that there was a negative correlation between the Q-index and the coefficient of variation, and the fluctuation of the propagation velocity could be inferred from the Q-index. Finally, we showed the results of applying the screen scores to muscle relaxation monitoring and confirmed its usefulness in clinical applications.
By applying the screen scores, we showed improved stability in speed estimation in C-SWE, and demonstrated the possibility of clinical applicability.
连续剪切波弹性成像（C-SWE）有望应用于便携式肌肉弹性诊断。为了建立诊断技术，有必要改进测量技术和定量测量精度。
在本研究中，我们研究了两个屏幕评分：质量指数（Q-index），用于确定功率多普勒图像的强度是否合适；以及剪切波传播方向指数（SWDI），用于确定剪切波传播的均匀性。
首先，我们对白噪声进行了数值模拟，发现当归一化 Q-index 大于 0.27 时，剪切波速度估计的变异系数小于 5%。此外，关于 SWDI，我们明确了剪切波传播方向的标准差与 SWDI 之间的关系。接下来，通过使用组织模拟体进行实验，评估了 Q-index 与估计的剪切波速度的变异系数之间的关系。结果表明，Q-index 与变异系数之间存在负相关，并且可以根据 Q-index 推断出传播速度的波动。最后，我们展示了将屏幕评分应用于肌肉松弛监测的结果，并证实了其在临床应用中的有用性。
通过应用屏幕评分，我们在 C-SWE 中的速度估计稳定性得到了提高，并证明了其临床应用的可能性。
