AParallel FDTD Scheme for Electromagnetic Analysis and Design of

This paper presents a parallel-computing FDTD simulator for electromagnetic analysis and design applications in Magnetic Resonance Imaging system. It is intended to be a complete, high-performance FDTD model of an MRI system including all temporal RF and low-frequency field generating units and electrical models of the patient. The developed MRI-dedicated FDTD algorithm is adapted to a parallel computing architecture with the MPI library. Its capabilities are illustrated in two distinct, large-scale field problems. One concerns the interaction of RF-fields with human tissue at high magnitude fields. The other includes the characterization of the temporal eddy currents induced in the cryostat vessel during gradient switching. The presented examples demonstrate the computational efficiency and extended analyses available due to the parallel FDTD framework. MPI library herein, field problems in MRI that require considerable memory resources can be solved much faster than using a single processor approach. Subsequently, in this work we implement MRI-dedicated cylindrical and Cartesian parallel FDTD schemes, which can be applied to different system geometries under a wide range of frequencies. The cylindrical FDTD method is demonstrated for the analysis of a low frequency (LF) problem, i.e., transient eddy currents in the cryostat induced during switching of a transverse gradient coil. The Cartesian FDTD method is parallelized for the comparative study of the interactions of RF-fields with male/female human models. The problems are treated with high spatial resolution, which is beyond the capability of the conventional non-parallelized FDTD algorithms. The simulation results indicate the enhanced performance of the developed FDTD simulator.