Fast RF Calculations for High Field MRI
Radio-frequency electromagnetic analysis of high field MRI coils is an indispensable task for the development of new coil designs, for optimization of existing coils through tuning and matching when they are loaded with human models, and to ensure safety through specific absorption rate (SAR) and temperature calculations. Finite difference time domain (FDTD)-based solvers have been the method of choice so far since they can easily handle the inhomogeneities in the human model and the utilization of low-cost GPU accelerators helped in reducing the simulation times. Nonetheless, these solvers still suffer long simulation times due to the resonant nature of MRI coils. Initial experiments and a recent publication show that frequency-domain hybrid methods, such as method of moments (MOM)-finite element method (FEM), are better suited to MRI experiments in terms of solution time. In addition, because they use surface-conformal tetrahedral meshes instead of cubical voxels, they are free from staircasing errors hence yield superior accuracy compared to FDTD. The cost of the FEM-MOM approach is that it needs more memory and high-performance computing clusters to handle high-resolution human models with low simulation times. MSI resources are therefore necessary for this work.