非均匀组织医学超声非线性传播仿真

发布时间：2018-06-08 04:41

本文选题：非线性声学 + 波动方程　；参考：《浙江大学学报(工学版)》2016年03期

【摘要】：为了实现仿真医学超声波在非均匀组织中的传播过程,建立超声非线性传播计算模型.由软组织中一阶非线性波动方程推导得出"声压-质点振动速度"耦合超声非线性波动方程以降低求解复杂度.采用k空间方法对非线性波动方程组求解,在保证数值计算精度的同时降低计算的内存占用量和计算时间.通过与一维问题的解析解和二维问题的时域有限差分(FDTD)求解结果对比,验证所述模型的精度.在空间采样率为声波波长的1/9、Courant-Friedrichs-Lewy(CFL)数为0.3的情况下,所述模型的平方误差为0.012 5%,而时域有限差分方法(FDTD)的平方误差为42.5%.利用体腹壁组织数字模型,进行医学超声谐波成像仿真,验证谐波成像较基波成像能够提高深部组织区域的图像质量.
[Abstract]:In order to simulate the propagation process of medical ultrasound in heterogeneous tissue, a nonlinear ultrasonic propagation model was established. From the first order nonlinear wave equation in soft tissue, the "acoustic pressure-particle vibration velocity" coupling ultrasonic nonlinear wave equation is derived to reduce the complexity of solution. The k-space method is used to solve the nonlinear wave equations, which not only ensures the accuracy of numerical calculation, but also reduces the memory consumption and computing time. The accuracy of the proposed model is verified by comparing with the analytical solution of the one-dimensional problem and the finite-difference FDTD solution of the two-dimensional problem. When the spatial sampling rate is 1 / 9 of the acoustic wavelength, the square error of the model is 0.012 and that of the finite-difference time-domain method is 42.5. The medical ultrasonic harmonic imaging simulation is carried out using the digital model of the abdominal wall tissue. It is proved that the harmonic imaging can improve the image quality of the deep tissue region compared with the fundamental imaging.
【作者单位】：浙江大学生物医学工程教育部重点实验室;
【基金】：中央高校基本科研业务费专项资金资助项目(2015FZA5019;2016FZA5015)
【分类号】：TB559

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