Gao Nuo, Zhu Shan-An, He Bin
School of Electrical Engineering, Zhejiang University, Hangzhou 310027, China.
J Zhejiang Univ Sci B. 2005 May;6(5):438-45. doi: 10.1631/jzus.2005.B0438.
We have developed a new three dimensional (3-D) conductivity imaging approach and have used it to detect human brain conductivity changes corresponding to acute cerebral stroke. The proposed Magnetic Resonance Electrical Impedance Tomography (MREIT) approach is based on the J-Substitution algorithm and is expanded to imaging 3-D subject conductivity distribution changes. Computer simulation studies have been conducted to evaluate the present MREIT imaging approach. Simulations of both types of cerebral stroke, hemorrhagic stroke and ischemic stroke, were performed on a four-sphere head model. Simulation results showed that the correlation coefficient (CC) and relative error (RE) between target and estimated conductivity distributions were 0.9245+/-0.0068 and 8.9997%+/-0.0084%, for hemorrhagic stroke, and 0.6748+/-0.0197 and 8.8986%+/-0.0089%, for ischemic stroke, when the SNR (signal-to-noise radio) of added GWN (Gaussian White Noise) was 40. The convergence characteristic was also evaluated according to the changes of CC and RE with different iteration numbers. The CC increases and RE decreases monotonously with the increasing number of iterations. The present simulation results show the feasibility of the proposed 3-D MREIT approach in hemorrhagic and ischemic stroke detection and suggest that the method may become a useful alternative in clinical diagnosis of acute cerebral stroke in humans.
我们开发了一种新的三维（3-D）电导率成像方法，并使用它来检测与急性脑卒中超对应的人脑电导率变化。所提出的磁共振电阻抗断层成像（MREIT）方法基于J-替代算法，并扩展到对三维受试者电导率分布变化进行成像。已进行计算机模拟研究以评估当前的MREIT成像方法。在四球头模型上对出血性卒中和缺血性卒中这两种类型的脑卒中进行了模拟。模拟结果表明，当添加的高斯白噪声（GWN）的信噪比（SNR）为40时，出血性卒中的目标电导率分布与估计电导率分布之间的相关系数（CC）和相对误差（RE）分别为0.9245±0.0068和8.9997%±0.0084%，缺血性卒中的分别为0.6748±0.0197和8.8986%±0.0089%。还根据不同迭代次数下CC和RE的变化评估了收敛特性。随着迭代次数的增加，CC单调增加，RE单调减小。目前的模拟结果表明所提出的三维MREIT方法在出血性和缺血性卒中检测中的可行性，并表明该方法可能成为人类急性脑卒中临床诊断中的一种有用替代方法。
