Scattering by implants during MRI: A simplified computational approach

During magnetic resonance imaging (MRI), an implanted lead present in a patient´s body scatters the radiofrquency (RF) field used for magnetic resonance. The resultant RF field can achieve very high values in the vicinity of the implant structure. The conduction currents flowing in tissue can cause dangerous resistive heating. Therefore scattering by implanted devices is an important safety issue in MR scanning. The scattering problem is large and computationally expensive. However the scattered field produced by the implant has a significant strength only in the vicinity of the implant and does not extend over a large tissue volume. Using this fact, a hybrid finite element-method of moments (FEM-MoM) formulation is used in this paper to compute the scattered fields of different implants.