Tomographic imaging of shear modulus elasticity of biological tissue based on ultrasonic measurement of internal displacement

基于超声波测量内部位移的生物组织剪切模量弹性断层成像

基本信息

批准号：
11680852
负责人：
YAMASHITA Yasuo
金额：
$ 2.24万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Palpation has been the clinical diagnostic modality to detect the changes in soft tissue elasticity, because the elasticity is usually related to some abnormal, pathological process. The goal of this study is to characterize tissue elasticity based on ultrasonic measurement of internal tissue deformation and displacement when the primary cardiac pulsation or the external mechanical force is applied to the soft tissue. A variational formulation is presented for the determination of the elasticity parameter of an isotropic, inhomogeneous, incompressible biological soft tissue, subject to external mechanical forces. Given a knowledge of the displacements throughout the tissue. A finite-element based model for static deformation is proposed for solving the distribution of the relative shear or Young's modulus of the tissue. The feasibility of the proposed method is demonstrated using the simulated deformation data of the simple three-dimensional inclusion problem. The results show that the … More relative shear modulus may be reconstructed from the displacement data measured locally in the region of interest within an isotropic, incompressible medium, and that the relative shear modulus can be recovered to some degree of accuracy from only 2-dimensional displacement data.Experiments on tissue mimicking phantoms were done. Mesurements are performed using real-time ultrasound and the sequences of RF echo signal returned from tissue ware digitized to estimate local tissue displacement. The 2-dimensional distribution of internal displacement was estimated using the spatio-temporal derivative of RF echo envelope signals, from which components of internal strain tensor were computed. Experimental results indicate that 2-dimensional fields of components of displacement can be estimated with the spatial resolution of 5mmx5mm. The distribution of the relative shear modulus based on displacement images was reconstructed. The elasticity of soft tissue can be characterized as the relative shear modulus computed from the local displacement data observed in the received RF echo signals. Less

触诊已成为检测软组织弹性变化的临床诊断方式，因为弹性通常与一些异常的病理过程有关，本研究的目的是基于超声测量内部组织变形和位移来表征组织弹性。提出了一种变分公式，用于确定受外部机械作用的各向同性、不均匀、不可压缩的生物软组织的弹性参数。考虑到整个组织的位移，提出了一种基于有限元的静态变形模型，用于求解组织的相对剪切或杨氏模量的分布，并使用模拟变形数据证明了该方法的可行性。简单的三维包含问题结果表明，相对剪切模量可以根据在各向同性、不可压缩介质内的感兴趣区域中局部测量的位移数据来重建。剪切模量可以仅从二维位移数据恢复到一定程度的精度。使用实时超声和从数字化组织器返回的射频回波信号序列进行了组织模拟模型实验，以估计局部组织。使用射频回波包络信号的时空导数来估计内部位移的二维分布，由此计算出内部应变张量的分量。可以用5mmx5mm的空间分辨率来估计位移分量。基于位移图像重建相对剪切模量的分布。软组织的弹性可以表征为根据接收到的局部位移数据计算出的相对剪切模量。射频回波信号较少。