三维磁共振电阻抗成像的改进分层灵敏度算法

针对人体组织电导率的三维成像问题,提出一种改进的分层灵敏度磁共振电阻抗重建算法.利用单方向磁感应强度信息,对三维电导率图像实行分层重建,每层重建仅利用该层磁通密度分量测量数据,然后对单层重建结果进行修正以获得三维电导率重建图像.三介质长方体模型上的仿真实验证明,改进的分层重建算法改善了层间串扰现象,可以获得比一般分层算法甚至整体算法更高的图像分辨率,而且重建时间较整体算法显著减少;基于人体腿模型的仿真实验表明该算法对复杂模型三维重构的可行性;最后通过仿体实验验证算法的重建效果.改进的分层灵敏度重建算法降低了灵敏度矩阵法的计算机硬件需求,减少了重建时间,对MREIT的三维重建具有较高的成像精度和求解效率.

Improved Algorithm Based on Sliced Sensitivity for Three-dimensional MREIT

An improved sliced sensitivity reconstruction algorithm is proposed for three-dimensional(3D) magnetic resonance electrical impedance tomography(MREIT).Using single component of magnetic flux density measured by a MR scanner,all slices are reconstructed respectively with a modification for 3D conductivity images.Simulation of a cubic model shows that the proposed algorithm improves interlayer crosstalk phenomenon with a higher image resolution than sliced reconstruction without modification and entire reconstruction algorithm.Computing time is significantly reduced.Simulation on a human leg model shows feasibility for complex imaging objects.Phantom results verify reconstruction algorithm in real measurements.The improved sliced sensitivity reconstruction algorithm reduces requirements for computer capability and reconstruction time of 3D MREIT with high imaging precision and efficiency.