Cylindrical 3D FDTD algorithm for the computation of low frequency transient eddy currents in MRI
Trakic A, Wang H, Liu F, Lopez H, Crozier S
The University of Queensland
Most Magnetic Resonance Imaging (MRI) spatial encoding techniques employ low-frequency pulsed magnetic field gradients that undesirably induce multi-exponentially decaying eddy currents in nearby conducting structures of the MRI system. A numerical description of eddy current associated temporal characteristics encountered during gradient switching is undeniably of great importance to the MRI field. A robust analysis scheme would allow more complete design and optimization of gradient coil/magnet combinations and gives indicative predictions of the pre-emphasis and B0-shift compensation waveforms required. This work outlines a three-dimensional (3D) finite-difference time-domain (FDTD) method in cylindrical coordinates for the modelling of low-frequency transient eddy currents in MRI.