基于动态孔径控制的剪切波传播速度检测方法  

A method of speed detection for shear wave propagation based on dynamic aperture control

作　　者：吴若愚[1] 朱新建[1] 陆彦邑 严博文[1] 高丹丹[1] 何庆华[1] 吴宝明[1] 

机构地区：[1]第三军医大学大坪医院野战外科研究所创伤、烧伤与复合伤国家重点实验室,重庆400042

出　　处：《北京生物医学工程》2016年第5期476-482,475,共8页Beijing Biomedical Engineering

基　　金：国家自然科学基金(11304382);创伤、烧伤与复合伤国家重点实验室自主研究课题[SKLZZ(Ⅱ)201403];第三军医大学校级课题(2012XJQ23)资助

摘　　要：目的超声剪切波弹性成像临床应用前景广阔,其中剪切波传播速度检测是其技术的核心步骤。针对在小焦距下传统基于静态孔径聚焦超声发射方式的剪切波传播速度检测准确度低的问题,本文提出一种基于动态孔径控制的剪切波传播速度检测方法。方法对不同的焦距以控制活跃阵元数目的方式动态控制孔径大小;采用峰值时间法结合最小二乘法计算剪切波传播速度;利用超声仿真平台FieldⅡ,采用控制变量法对多个小焦距下的声辐射力场、标记点"位移-时间"曲线及剪切波传播速度进行了仿真研究。结果本方法可有效抑制栅瓣的出现,能获取呈现出明显主峰的走势良好的标记点"位移-时间"曲线。剪切波传播速度检测结果与理论值的相对误差更低,例如在焦距为7 mm时,与理论值相对误差降低了16.585%;在焦距为9 mm时,降低了15.205%。结论基于动态孔径控制的剪切波传播速度检测方法能合理控制小焦距下的声辐射力,提升剪切波传播速度检测准确度,为超声剪切波弹性成像技术的进一步发展提供理论依据。Objective Ultrasound-based shear wave elasticity imaging has great potential and development prospects in clinical practice. The speed detection for shear wave propagation is the key step in this technique. The accuracy of speed detection for shear wave propagation based on static aperture focused ultrasound emission mode is reduced as the focal length is small. To solve this problem,a detection method based on dynamic aperture control is proposed in this paper. Methods For the different focal length,active array elements were adopted for dynamic control on the size of aperture. The method of ＂time to peak displacement＂,combining with least square algorithm,was used to calculate the propagation speed of shear wave. The method of control variables was adopted for study on acoustic radiation force field,＂displacementtime curves＂for the marked points and the propagation speed of shear wave in the software platform FieldⅡ.Results Grating lobes were eliminated effectively and ideal ＂displacement-time curves＂with a clear peak were obtained for the marked points with the proposed method.The relative errors reduced compared to traditional method. For example,when the focal length was 7 mm,the relative error reduced 16. 585%; when the focal length was 9 mm, the relative error reduced 15. 205%.Conclusions For the small focal length, the proposedmethod can control the acoustic radiation force properly and increase the accuracy of speed detection for shear wave propagation. The study provides a theoretical basis for the improvement of shear wave-based ultrasound elasticity imaging.

关 键 词：剪切波传播 速度 动态孔径控制 焦距 声辐射力 

分 类 号：R318.01[医药卫生—生物医学工程] R445.1[医药卫生—基础医学]