Imaging electrical impedance from acoustic measurements by means of magnetoacoustic tomography with magnetic induction (MAT-MI)
Imaging electrical impedance from acoustic measurements by means of magnetoacoustic tomography with magnetic induction (MAT-MI)
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DOI：
10.1109/tbme.2006.883827
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发表时间：
2007-02-01
影响因子：
4.6
通讯作者：
He, Bin
中科院分区：
文献类型：
--
作者：
Li, Xu;Xu, Yuan;He, Bin
我们对用于电阻抗成像的磁感应磁声断层扫描（MAT-MI）进行了计算机模拟和实验研究。在 MAT-MI 中，将要成像的物体放置在静态磁场中，同时施加脉冲磁刺激以在物体中感应涡流。在静磁场中，洛伦兹力作用于涡流并引起物体的声振动。然后测量物体周围传播的声波以重建电阻抗分布。在本模拟研究中，使用两层球形模型。设置模型的参数，例如样本大小、电导率值、静态和脉冲磁场的强度，以模拟生物组织样本的特征和可行的实验约束。在正演模拟中，使用泊松方程求解电势和电流密度，并计算声压作为正演解。然后根据样品周围的模拟压力分布重建电阻抗分布。目前的计算机模拟结果表明，MAT-MI可以重建具有高空间分辨率和高对比度的生物组织电导率图像。 MAT-MI 在提供包含阻抗相关信息的高空间分辨率图像方面的可行性也在模型实验中得到了证明。
We have conducted computer simulation and experimental studies on magnetoacoustic-tomography with magnetic induction (MAT-MI) for electrical impedance imaging. In MAT-MI, the object to be imaged is placed in a static magnetic field, while pulsed magnetic stimulation is applied in order to induce eddy current in the object. In the static magnetic field, the Lorentz force acts upon the eddy current and causes acoustic vibrations in the object. The propagated acoustic wave is then measured around the object to reconstruct the electrical impedance distribution. In the present simulation study, a two-layer spherical model is used. Parameters of the model such as sample size, conductivity values, strength of the static and pulsed magnetic field, are set to simulate features of biological tissue samples and feasible experimental constraints. In the forward simulation, the electrical potential and current density are solved using Poisson's equation, and the acoustic pressure is calculated as the forward solution. The electrical impedance distribution is then reconstructed from the simulated pressure distribution surrounding the sample. The present computer simulation results suggest that MAT-MI can reconstruct conductivity images of biological tissue with high spatial resolution and high contrast. The feasibility of MAT-MI in providing high spatial resolution images containing impedance-related information has also been demonstrated in a phantom experiment.