Department of Diagnostic Radiology, School of Medicine, Yale University, New Haven, CT 06520, USA.
IEEE Trans Med Imaging. 2011 Mar;30(3):828-37. doi: 10.1109/TMI.2010.2098035. Epub 2010 Dec 10.
Magnetic resonance electrical impedance tomography (MREIT) is a method for reconstructing a three-dimensional image of the conductivity distribution in a target volume using magnetic resonance (MR). In MREIT, currents are applied to the volume through surface electrodes and their effects on the MR induced magnetic fields are analyzed to produce the conductance image. However, current injection through surface electrodes poses technical problems such as the limitation on the safely applicable currents. In this paper, we present a new method called magnetic resonance driven electrical impedance tomography (MRDEIT), where the magnetic resonance in each voxel is used as the applied magnetic field source, and the resultant electromagnetic field is measured through surface electrodes or radio-frequency (RF) detectors placed near the surface. Because the applied magnetic field is at the RF frequency and eddy currents are the integral components in the method, a vector wave equation for the electric field is used as the basis of the analysis instead of a quasi-static approximation. Using computer simulations, it is shown that complex permittivity images can be reconstructed using MRDEIT, but that improvements in signal detection are necessary for detecting moderate complex permittivity changes.
磁共振电阻抗断层成像（MREIT）是一种利用磁共振（MR）重建目标体积内电导率分布三维图像的方法。在 MREIT 中，电流通过表面电极施加到体积中，并分析其对 MR 感应磁场的影响，以产生电导率图像。然而，通过表面电极进行电流注入存在技术问题，例如安全适用电流的限制。在本文中，我们提出了一种称为磁共振驱动电阻抗断层成像（MRDEIT）的新方法，其中每个体素中的磁共振用作施加磁场源，并且通过放置在表面附近的表面电极或射频（RF）探测器测量所得电磁场。由于施加的磁场处于 RF 频率并且涡流是该方法的组成部分，因此使用电场的矢量波动方程作为分析的基础，而不是准静态近似。通过计算机模拟，表明可以使用 MRDEIT 重建复介电常数图像，但需要改进信号检测以检测中等复介电常数变化。
