IEEE Trans Ultrason Ferroelectr Freq Control. 2017 Apr;64(4):660-668. doi: 10.1109/TUFFC.2017.2652143. Epub 2017 Jan 11.
Quantitative ultrasound elastography is increasingly being used in the assessment of chronic liver disease. Many studies have reported ranges of liver shear wave velocity values for healthy individuals and patients with different stages of liver fibrosis. Nonetheless, ongoing efforts exist to stabilize quantitative ultrasound elastography measurements by assessing factors that influence tissue shear wave velocity values, such as food intake, body mass index, ultrasound scanners, scanning protocols, and ultrasound image quality. Time-to-peak (TTP) methods have been routinely used to measure the shear wave velocity. However, there is still a need for methods that can provide robust shear wave velocity estimation in the presence of noisy motion data. The conventional TTP algorithm is limited to searching for the maximum motion in time profiles at different spatial locations. In this paper, two modified shear wave speed estimation algorithms are proposed. The first method searches for the maximum motion in both space and time [spatiotemporal peak (STP)]; the second method applies an amplitude filter [spatiotemporal thresholding (STTH)] to select points with motion amplitude higher than a threshold for shear wave group velocity estimation. The two proposed methods (STP and STTH) showed higher precision in shear wave velocity estimates compared with TTP in phantom. Moreover, in a cohort of 14 healthy subjects, STP and STTH methods improved both the shear wave velocity measurement precision and the success rate of the measurement compared with conventional TTP.
定量超声弹性成像在慢性肝病评估中应用日益广泛。许多研究报告了健康个体和不同纤维化阶段肝病患者的肝脏剪切波速度值范围。然而，人们仍在努力通过评估影响组织剪切波速度值的因素来稳定定量超声弹性成像测量，如饮食、体重指数、超声扫描仪、扫描方案和超声图像质量。达峰时间（TTP）方法已常规用于测量剪切波速度。然而，在存在噪声运动数据的情况下，仍需要能够提供稳健剪切波速度估计的方法。传统的 TTP 算法仅限于在不同空间位置的时间谱中搜索最大运动。在本文中，提出了两种改进的剪切波速度估计算法。第一种方法在空间和时间上搜索最大运动[时空峰值（STP）]；第二种方法应用幅度滤波器[时空阈值（STTH）]选择运动幅度高于阈值的点，以进行群速度估计。与在体模中的 TTP 相比，两种提出的方法（STP 和 STTH）在剪切波速度估计方面具有更高的精度。此外，在 14 名健康受试者的队列中，与传统的 TTP 相比，STP 和 STTH 方法提高了剪切波速度测量的精度和成功率。
