Department of Biomedical Engineering, Kyung Hee University, Seoul, Korea.
Phys Med Biol. 2010 Dec 21;55(24):7523-39. doi: 10.1088/0031-9155/55/24/009. Epub 2010 Nov 19.
Magnetic resonance electrical impedance tomography (MREIT) is to visualize the internal current density and conductivity of an electrically conductive object. Injecting current through surface electrodes, we measure one component of the induced internal magnetic flux density using an MRI scanner. In order to reconstruct the conductivity distribution inside the imaging object, most algorithms in MREIT have required multiple magnetic flux density data by injecting at least two independent currents. In this paper, we propose a direct method to reconstruct the internal isotropic conductivity with one component of magnetic flux density data by injecting one current into the imaging object through a single pair of surface electrodes. Firstly, the proposed method reconstructs a projected current density which is a uniquely determined current from the measured one-component magnetic flux density. Using a relation between voltage potential and current, based on Kirchhoff's voltage law, the proposed method is designed to use a combination of two loops around each pixel from which to derive an implicit matrix system for determination of the internal conductivity. Results from numerical simulations demonstrate that the proposed algorithm stably determines the conductivity distribution in an imaging slice. We compare the reconstructed internal conductivity distribution using the proposed method with that using a conventional method with agarose gel phantom experiments.
磁共振电阻抗断层成像（MREIT）用于可视化导电物体的内部电流密度和电导率。通过表面电极注入电流，我们使用 MRI 扫描仪测量感应内部磁通密度的一个分量。为了重建成像物体内部的电导率分布，MREIT 中的大多数算法都需要通过至少注入两个独立电流来获得多个磁通量密度数据。在本文中，我们提出了一种通过在成像物体中通过一对表面电极注入一个电流来从测量的单分量磁通量密度直接重建各向同性内部电导率的方法。首先，所提出的方法从测量的单分量磁通量密度中重建出一个投影电流密度，这是一个唯一确定的电流。基于基尔霍夫电压定律，利用电压电位与电流之间的关系，该方法设计为使用围绕每个像素的两个环的组合，从该组合中得出用于确定内部电导率的隐式矩阵系统。数值模拟结果表明，所提出的算法可以稳定地确定成像切片中的电导率分布。我们使用琼脂糖凝胶体模型实验比较了所提出的方法与常规方法的重建内部电导率分布。
