头部组织感应电流磁共振电阻抗成像仿真研究

Simulation Study on Induced Current Magnetic Resonance Electrical Impedance Tomography of Brain Tissues

将感应电流磁共振电阻抗成像(IC-MREIT)应用于人体头部组织电导率重构,并在三层球头模型上进行仿真研究。首先建立二次磁场Z方向磁感应强度摄动对有限元头模型中单元电导率摄动的灵敏度矩阵;然后分析系统中激励线圈个数、激励线圈与三层球头模型相对位置及激励线圈半径等因素对灵敏度矩阵性态的影响,为IC-MREIT系统激励线圈优化设计提供指导;最后采用灵敏度矩阵法对三层球头模型非均匀电导率分布进行重构,仿真结果证明IC-MREIT技术用于重构头部组织电导率分布是可行的,在无创头部组织电导率检测领域具有潜在的应用价值。

Induced current magnetic resonance electrical impedance tomography （IC-MREIT） was used to reconstruct electrical conductivity of the brain tissues. A series of simulation studies were conducted using the three-sphere head model. Firstly, the sensitivity matrix was built according to the perturbation of secondary magnetic flux density with respect to the perturbation of clement conductivity of finite-element head model. Secondly, the effects of the number of excitation coils, as well as the relative placement between them and the three-sphere head model and their radii on property of sensitivity matrix were analyzed, for the purpose of guiding rationale design of excitation coils in IC-MREIT system. Finally, the sensitivity matrix method was adopted to reconstruct non-uniform electrical conductivity distribution of the three-sphere head model. The present simulation study indicates the feasibility and potential applications of IC-MREIT to reconstruct the electrical conductivity distribution of brain tissues.