Application of eddy current formulations to magnetic resonance imaging

The calculation of 3-D radio-frequency (RF) fields with the aid of an eddy current formulation based on finite elements is described. It is shown that the displacement current density in the first Maxwell equation can be taken into account by making the conductivity a complex quantity. The validity of this formulation has been verified by calculating a conducting sphere influenced by a homogeneous time-harmonic RF field. The numerical results are compared with an analytical solution. The formulation described has been applied to calculate a 3-D phantom with regions of different conducting materials. For this phantom, measured results obtained by magnetic resonance imaging are compared.<
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