Magnetic resonance specific integral equation solver based on precomputed numerical Green functions

Abstract

We propose a methodology for the fast analysis of the EM fields generated by the transmit radio-frequency coils when operating in the presence of realistic human body models (RHBM). This work is driven by the need of fast and accurate specific absorption rate (SAR) prediction and coil design analysis in the context of high-field Magnetic Resonance Imaging (MRI). These RHBM are highly inhomo-geneous voxelized models, whose EM analysis can be expensive. In our approach, the electromagnetic effect of the complex RHBM is captured by a numerically generated Green function (GF). For MRI problems, the electric current sources are generally confined to a very small region where the coils could be located. The RHBM GF is required only for that specific source region and can therefore be effectively pre-computed and stored. These GF can be then assembled and combined with standard surface integral equation based solvers to model the actual coil design, allowing for a fast analysis of the complete problem.