基于经验模态分解和减影法高强度聚焦超声离体牛肝组织损伤的监控成像  

Monitoring imaging of beef liver lesions using high intensity focused ultrasound based on empirical mode decomposition and subtraction method

作　　者：宋卫东[1] 

机构地区：[1]西安交通大学生命科学与技术学院生物医学工程系,陕西省西安市710049

出　　处：《中国组织工程研究》2012年第40期7520-7527,共8页Chinese Journal of Tissue Engineering Research

基　　金：科技部国家基础研究973项目(2011CB707903)~~

摘　　要：背景:聚焦超声照射后,聚焦区域组织会在B超图像对应的位置形成强回声现象,这可能会在软组织中形成声阻抗差,对损伤检测造成干扰。目的:提出一种基于经验模态分解和减影法的损伤成像方法,用于检测高强度聚焦超声治疗过程中的组织损伤。方法:结合经验模态分解和减影算法各自的优点,针对牛肝组织回波信号信噪比较低的特点,利用经验模态分解对治疗前后超声回波信号进行自适应分解以消除噪声信号,然后对治疗后的每帧去噪信号和治疗前的去噪信号进行减影,最后对数据经过希尔伯特变换和对数变换后成像。结果与结论:利用结合经验模态分解的减影方法获得了离体牛肝组织的监控图像及相应的B超图像和直接减影图。实验结果表明,结合经验模态分解的减影成像方法能够较有效地对聚焦超声引起的软组织损伤进行成像,并能检测到B超成像不能检测到的较小组织损伤,且其对比度和分辨率均高于直接减影成像。BACKGROUND： After focused ultrasound irradiation, focused regional organizations will form the strong echo phenomenon in the corresponding position of the B-mode images, which may form acoustic impedance difference in the soft tissue and may disrupt the damage detection. OBJECTIVE： To propose an imaging method based on the empirical mode decomposition and subtraction method for the detection of tissue lesion induced by high intensity focused ultrasound. METHODS： Combined the advantage of empirical mode decomposition with that of subtraction method, ultrasonic echo signal was decomposed adaptively by empirical mode decomposition method, and then, subtraction method was executed to the denoised. Finally, monitoring image of lesions was completed after Hilbert transformation and log conversion. RESULTS AND CONCLUSION： The experiments of bovine liver in vitro were implemented. The differential images combined with the empirical mode decomposition were acquired as well as corresponding B-mode images and the differential images. The results of experiment showed that the proposed method can characterize the high intensity focused ultrasound induced lesions in soft tissue effectively. It can identify the smaller lesions which can not be detected in B-mode images and offer higher contrast and resolution than that of the differential images.

关 键 词：高强度聚焦超声 超声成像 经验模态分解 减影成像 软组织损伤 对比度 分辨率 组织工程 

分 类 号：R318[医药卫生—生物医学工程]