MRI-Based Electrical Property Retrieval by Applying the Finite-Element Method (FEM)

Abstract

In this study, the finite-element method is applied to reconstruct the electrical properties (conductivity and permittivity) maps of media with 1-D, 2-D, and 3-D inhomogeneities based on the RF magnetic field distributions in a magnetic resonance imaging (MRI) system. The proposed method handles the discontinuity of electrical properties well. It therefore shows high accuracy at the boundary compared to retrieval methods in the literature. The method has successfully been validated using both analytical and numerical data. Moreover, the noise sensitivity of the proposed method is studied. Good accuracy of retrievals can be obtained when proper coils are chosen (e.g., transverse electromagnetic coils). It is an effective approach showing one step further towards accurate electrical property mapping based on MRI data. It helps to pave the way to accurate calculations of specific absorption rate distributions and temperature distributions of human body under MRI scans, which are crucial for the evaluation of the safety of MRI systems. Moreover, the increased accuracy of the electrical property maps of human body show their potential to be a diagnostic tool for tumors and cancers, especially at their early stages. Following-up research is expected to make the proposed method robust and practical for clinical applications.