New transmission line model of an insulated cable embedded in gel for MRI radiofrequency interaction hazard evaluation as an alternative to the transfer function model

Object: To demonstrate the possibility to model the power deposited at the electrode of an insulated cable in gel at 64MHz with a transmission line model with a strictly passive electrode model. This offers a more related to physics alternative to the transfer function model. The equivalence between both models is shown.Materials and Methods: In a first step, the possibility of modeling an insulated cable with a transmission line model was analyzed through full-wave numerical simulations. An electrode model that has a physical meaning was proposed. The transmission line model predictions were confronted to experimental and simulated data of the transfer function of a cable and of the resonant behavior as a function of length of cables with different termination conditions.Results: The assumption of a transmission line model which underlies the transfer function model is right for a simple cable embedded in tissue imitating gel. A transmission line model extracted from a transfer function allows to predict the resonant behavior of two cables with different termination conditions.Conclusion: A transmission line model of an insulated cable embedded in tissue imitating gel offers a more directly related to physics alternative to the transfer function model.