基于磁致边界振动希尔伯特变换的电导率重建简化算法

发布时间：2019-03-01 16:13

【摘要】：磁声成像是一种结合电阻抗成像和超声成像优点的多物理场耦合新型成像方法,能实现组织的电阻抗对比成像,重建组织内部电阻抗分布的边界.本研究首先利用强指向性换能器来提高磁致振动检测的方向精确性,通过磁声声压导数实现边界振动声源法向声压的提取;然后从换能器的接收声压出发,利用三维空间的格林函数推导了一种基于磁致边界振动法向声压的电导率重建算法,明确了重建过程中声压及其导数的物理意义;最后建立了圆柱坐标下的柱状扫描系统,对双层偏心圆柱组织模型所产生的声压和换能器所接收到的磁声声波进行了模拟,利用Hilbert变换实现波簇包络定位和相位分析,恢复磁致边界振动声压,重建扫描面的二维电导率分布和模型截面具有较高的一致性,不但获得了组织的边界信息,还实现了组织内部电导率分布的精确重建.所提出的基于磁致边界振动希尔伯特变换的电阻抗重建简化算法为组织病变的电阻抗成像和磁声诊断提供了新方法.
[Abstract]:Magnetic acoustic imaging is a new method of multi-physical field-coupled imaging combined with the advantages of electrical impedance imaging and ultrasonic imaging, which can realize the contrast imaging of the electrical impedance of the tissue and reconstruct the boundary of the electrical impedance distribution inside the tissue. In this study, a strong directional transducer is used to improve the directional accuracy of the magnetic vibration detection, and the normal sound pressure of the boundary vibration sound source is extracted by the magnetic sound pressure derivative, and then the sound pressure of the transducer is obtained from the received sound pressure of the transducer, The electric conductivity reconstruction algorithm based on the normal sound pressure of the magnetic boundary is derived by the Green's function of the three-dimensional space, the physical meaning of the sound pressure and its derivative in the reconstruction process is defined, and the cylindrical scanning system under the cylindrical coordinates is finally established. the sound pressure generated by the double-layer eccentric cylindrical tissue model and the magnetic sound acoustic wave received by the transducer are simulated, the wave cluster envelope positioning and the phase analysis are realized by using the Hilbert transform, the magnetic sound pressure of the magnetic boundary is recovered, The two-dimensional conductivity distribution and the model cross-section of the reconstructed scan plane have higher consistency, not only the boundary information of the tissue is obtained, but also the accurate reconstruction of the conductivity distribution inside the tissue is realized. The proposed electrical impedance reconstruction algorithm based on the magnetic boundary vibration Hilbert transform provides a new method for the electrical impedance imaging and the magnetic acoustic diagnosis of the tissue lesions.
【作者单位】：南京师范大学物理科学与技术学院;
【基金】：国家自然科学基金(11604156) 江苏省高校自然科学研究项目(16KJB430020) 江苏省自然科学基金(BK20161013) 中国博士后科学基金(2016M591874)
【分类号】：O441

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