A High Performance FDTD Scheme for MRI Applications

Results and Discussion: We demonstrate the use of the proposed parallel FDTD scheme in the analysis of low frequency transient eddy currents in nearby conducting structures when pulsing magnetic field gradients. We assess the Specific Absorption Rate (SAR) during the interaction of RF fields with inhomogeneous human tissues (both female and male models) within a linearly polarized birdcage resonator model at 340 MHz. Fig. 3 shows a comparison of normalized SAR between the female (NAOMI) and male (NORMAN) voxel phantom in a birdcage resonator. Fig. 4 illustrates spatial normalized axial magnetic and azimuthal electric fields in the symmetric gradient coil system and radiation shields for a single gradient pulse of 10 T/m/s. The devised parallel routine on the cluster of processors was approximately 10 times faster than when a single processor was used. Conclusion: An optimised and robust parallel FDTD scheme, which can be easily implemented using the MPI library, has been presented for MRI applications. Computational benefits of the proposed parallel FDTD structure has been demonstrated on two typical low and high frequency field problems. It has been shown that parallel computing can increase the computational efficiency and power. This is of considerable advantage to the advancement of MRI technology. Fig. 3 – Normalized SAR profiles inside a female model (NAOMI, left) and comparisons of SAR between female and male model (NORMAN, right). Fig.4 – System set-up and normalized fields (left: axial magnetic field; right: azimuthal electric field in the middle layer of each radiation shield).