A New FDTD Method for the Study of MRI Pulsed Field Gradient- Induced Fields in the Human Body

In modern MRI, patients are exposed to strong, rapidly switched magnetic field gradients that may be able to elicit nerve stimulation (1-14). This paper provides the numerical results of an investigation into induced current spatial distributions inside human tissue when exposed to these pulsed magnetic field gradients. Conventional FDTD methods are unable to model these effects as the effective frequencies of the input source are less than 100kHz or so, relatively low for FDTD calculations. A new High Definition FDTD variant was developed to operate over this bandwidth and a number of body and gradient models are analysed using the new method.