1.5T、3T和7T下MR EPT核心算法在非均匀组织中的误差比较

Comparison of the Reconstruction Errors of the Currently Popular Algorithm of MR EPT in an Inhomogeneous Phantom at 1.5, 3 and 7T

本文比较了1.5T、3T和7T磁共振介电特性断层成像(MR EPT)核心算法在介电特性非均匀组织中的重建误差。首先,建立介电特性非均匀的电磁模型,仿真计算该模型在不同场强电磁场下的射频发射电磁场分布;其次,利用MR EPT核心算法计算得到成像区域组织介电特性分布;最后,比较不同场强非均匀组织介电特性重建结果的误差。结果表明,当场强为1.5T时,重建结果最大相对误差和平均相对误差都最大,而在7T场强下,重建结果的最大相对误差和平均相对误差都最小,不同场强下该算法的重建误差不同,重建误差随场强的增大而减小。

This work compared the reconstruction errors（REs） of the currently popular algorithm of MR-based electrical properties tomography（MR EPT） while applied in inhomogeneous object at 1.5, 3 and 7 T. The B1＋ data of an inhomogeneous phantom were simulated at the three resonance frequencies. The currently popular algorithm of MR EPT was used to reconstruct the electrical property（EP） distributions inside the phantom. The absolute RE（a RE） and relative RE（r RE） maps in addition to the mean r REs were calculated to compare the REs occurring at different resonance frequencies. The maximums of maximum and mean r REs were observed at 1.5T, on the contrary, the minimums of maximum and mean r REs were observed at 7T. The REs varied with different resonance frequencies, and the REs decreased as the resonance frequency increased.