注入及感应电流磁共振电阻抗成像对比

摘要

为了对比注入电流磁共振电阻抗成像(MREIT)及感应电流磁共振电阻抗成像(IC-MREIT)用于重构人体头部组织电导率分布的性能,分别在3层球头模型及包含5种组织的真实头模型上进行仿真.正问题仿真结果表明:在满足人体安全性要求的前提下,2种成像方法在头部组织内产生的电流密度的强度处于同一数量级,但IC-MREIT产生的电流密度略大且分布受颅骨影响较小.基于J-substitution算法的逆问题仿真结果表明:对于3层球头模型,IC-MREIT能够在较少的迭代次数内,以更高的精度重构出电导率分布；对于真实头模型,MREIT具有更好的收敛特性和成像精度.%The simulations were conducted on the three-sphere head model and five-compartment realistic head model in order to evaluate the performance of the injected current magnetic resonance electrical impedance tomography (MREIT) and the induced current magnetic resonance electrical impedance tomography (IC-MREIT) to image the conductivity distribution of head-brain tissues. The simulation results of the forward problem show that the current densities in the head produced by MREIT and IC-MREIT are of the same order of magnitude when the safety requirement is satisfied. The current density produced by IC-MREIT is a little larger and is less affected by the skull. The simulation results of the inverse problem based on the J-substitution algorithm indicate that IC-MREIT can image the conductivity distribution with higher accuracy than MREIT in less iterations for the three-sphere head model; the convergence behavior and imaging precision of MREIT are superior to IC-MREIT for the realistic head model.