Zhou Zhuhuang, Wu Shuicai, Lin Man-Yen, Fang Jui, Liu Hao-Li, Tsui Po-Hsiang
1 College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China.
2 Faculty of Information Technology, Beijing University of Technology, Beijing, China.
Ultrason Imaging. 2018 May;40(3):171-189. doi: 10.1177/0161734618756101. Epub 2018 Mar 5.
In this study, the window-modulated compounding (WMC) technique was integrated into three-dimensional (3D) ultrasound Nakagami imaging for improving the spatial visualization of backscatter statistics. A 3D WMC Nakagami image was produced by summing and averaging a number of 3D Nakagami images (number of frames denoted as N) formed using sliding cubes with varying side lengths ranging from 1 to N times the transducer pulse. To evaluate the performance of the proposed 3D WMC Nakagami imaging method, agar phantoms with scatterer concentrations ranging from 2 to 64 scatterers/mm were made, and six stages of fatty liver (zero, one, two, four, six, and eight weeks) were induced in rats by methionine-choline-deficient diets (three rats for each stage, total n = 18). A mechanical scanning system with a 5-MHz focused single-element transducer was used for ultrasound radiofrequency data acquisition. The experimental results showed that 3D WMC Nakagami imaging was able to characterize different scatterer concentrations. Backscatter statistics were visualized with various numbers of frames; N = 5 reduced the estimation error of 3D WMC Nakagami imaging in visualizing the backscatter statistics. Compared with conventional 3D Nakagami imaging, 3D WMC Nakagami imaging improved the image smoothness without significant image resolution degradation, and it can thus be used for describing different stages of fatty liver in rats.
在本研究中，窗口调制复合（WMC）技术被集成到三维（3D）超声中值成像中，以改善背散射统计量的空间可视化。通过对一系列使用边长从换能器脉冲的1倍到N倍变化的滑动立方体形成的3D中值图像（帧数记为N）进行求和与平均，生成3D WMC中值图像。为评估所提出的3D WMC中值成像方法的性能，制作了散射体浓度范围为2至64个散射体/mm的琼脂体模，并通过蛋氨酸-胆碱缺乏饮食在大鼠中诱导出六个阶段的脂肪肝（零周、一周、两周、四周、六周和八周）（每个阶段三只大鼠，总共n = 18）。使用带有5MHz聚焦单元素换能器的机械扫描系统进行超声射频数据采集。实验结果表明，3D WMC中值成像能够表征不同的散射体浓度。背散射统计量通过不同数量的帧数进行可视化；N = 5降低了3D WMC中值成像在可视化背散射统计量时的估计误差。与传统的3D中值成像相比，3D WMC中值成像在不显著降低图像分辨率的情况下提高了图像平滑度，因此可用于描述大鼠脂肪肝的不同阶段。
