Ahmed Rifat, Trahey Gregg E
IEEE Trans Ultrason Ferroelectr Freq Control. 2024 Oct;71(10):1244-1254. doi: 10.1109/TUFFC.2024.3440832. Epub 2024 Oct 10.
Sound speed estimation can potentially correct the focusing errors in medical ultrasound. Maximizing the echo spatial coherence as a function of beamforming sound speed is a known technique to estimate the average sound speed. However, beamformation with changing sound speed causes a spatial shift of the echo signals resulting in noise and registration errors in the average sound speed estimates. We show that the spatial shift can be predicted and corrected, leading to superior sound speed estimates. Methods are presented for axial and 2-D location correction. Methods were evaluated using simulations and experimental phantom data. The location correction strategies improved the variance of sound speed estimates and reduced artifacts in the presence of strong backscatter variations. Limitations of the proposed methods and potential improvement strategies were evaluated.
声速估计有可能校正医学超声中的聚焦误差。将回波空间相干性作为波束形成声速的函数进行最大化是一种已知的估计平均声速的技术。然而，声速变化时的波束形成会导致回波信号的空间偏移，从而在平均声速估计中产生噪声和配准误差。我们表明，可以预测和校正这种空间偏移，从而实现更优的声速估计。本文提出了轴向和二维位置校正的方法。使用模拟和实验体模数据对这些方法进行了评估。在存在强后向散射变化的情况下，位置校正策略改善了声速估计的方差并减少了伪像。评估了所提出方法的局限性和潜在的改进策略。
