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Coupled transfer function model for the evaluation of implanted cables safety in MRI
Author(s) -
Kabil Julie,
Felblinger Jacques,
Vuissoz PierreAndré,
Missoffe Alexia
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28146
Subject(s) - transfer function , coupling (piping) , work (physics) , transfer (computing) , function (biology) , heat transfer , constant (computer programming) , mechanics , coupling constant , field (mathematics) , dielectric heating , time constant , materials science , biomedical engineering , computational physics , computer science , nuclear magnetic resonance , physics , thermodynamics , optoelectronics , mathematics , electrical engineering , composite material , medicine , evolutionary biology , parallel computing , biology , pure mathematics , programming language , engineering , dielectric , particle physics
Purpose Multiple medical‐device leads implanted next to each other are often encountered in clinical practice. The aim of this work is to study a coupled transfer function model to evaluate the safety of these coupled leads submitted to the RF field of a 1.5T MRI scanner for a constant distance between both leads. Methods The effect of coupling on the heating of 2 cables with different termination conditions is evaluated experimentally. The coupled and single transfer functions are determined experimentally and used to predict the relative temperature increases of both cables alone and coupled. Two different coupled models, an additive model and a global model, are proposed. The coupled transfer functions are also simulated. Results The coupling between cables has a strong influence on the resulting heating at the electrodes. The coupled additive transfer function model is a relevant tool to evaluate the heating of coupled leads separated by a constant distance. The global model underestimates the heating in one of the coupled cases by about 30%. The measured coupled transfer functions coincide with the simulated models. Conclusion It is necessary to take into account the coupling effect between leads to evaluate the safety of implanted devices. This work shows that, in the case of 2 cables separated by a constant distance, that an experimentally determined coupled transfer function allows estimation of the heating of the 2 electrodes for a given incident field. Further work should take into account the in vivo varying distance between the 2 cables.