Department of Radiology, Stanford University School of Medicine, Stanford, California, USA; Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
Ultrasound Med Biol. 2022 Nov;48(11):2217-2228. doi: 10.1016/j.ultrasmedbio.2022.06.007. Epub 2022 Aug 13.
Contrast-enhanced ultrasound (CEUS) acquisitions of focal liver lesions are affected by motion, which has an impact on contrast signal quantification. We therefore developed and tested, in a large patient cohort, a motion compensation algorithm called the Iterative Local Search Algorithm (ILSA), which can correct for both periodic and non-periodic in-plane motion and can reject frames with out-of-plane motion. CEUS cines of 183 focal liver lesions in 155 patients from three hospitals were used to develop and test ILSA. Performance was evaluated through quantitative metrics, including the root mean square error and R in fitting time-intensity curves and standard deviation value of B-mode intensities, computed across cine frames), and qualitative evaluation, including B-mode mean intensity projection images and parametric perfusion imaging. The median root mean square error significantly decreased from 0.032 to 0.024 (p < 0.001). Median R significantly increased from 0.88 to 0.93 (p < 0.001). The median standard deviation value of B-mode intensities significantly decreased from 6.2 to 5.0 (p < 0.001). B-Mode mean intensity projection images revealed improved spatial resolution. Parametric perfusion imaging also exhibited improved spatial detail and better differentiation between lesion and background liver parenchyma. ILSA can compensate for all types of motion encountered during liver CEUS, potentially improving contrast signal quantification of focal liver lesions.
对比增强超声（CEUS）对肝脏局灶性病变的采集受运动影响，这会影响对比信号的定量。因此，我们开发并在一个大型患者队列中测试了一种称为迭代局部搜索算法（ILSA）的运动补偿算法，该算法可以纠正平面内的周期性和非周期性运动，并可以拒绝平面外运动的帧。来自三家医院的 155 名患者的 183 个肝脏局灶性病变的 CEUS 电影用于开发和测试 ILSA。通过定量指标评估性能，包括拟合时间-强度曲线的均方根误差和 R，以及跨电影帧计算的 B 模式强度的标准差值）和定性评估，包括 B 模式平均强度投影图像和参数灌注成像。中位均方根误差从 0.032 显著降低至 0.024（p<0.001）。中位数 R 从 0.88 显著增加至 0.93（p<0.001）。B 模式强度的标准差值从 6.2 显著降低至 5.0（p<0.001）。B 模式平均强度投影图像显示出空间分辨率的提高。参数灌注成像也显示出更好的空间细节和病变与背景肝实质之间更好的区分。ILSA 可以补偿肝脏 CEUS 期间遇到的所有类型的运动，从而有可能改善肝脏局灶性病变的对比信号定量。
