Validating Numerical Simulations to Support Experimental Testing of MRI Gradient-Induced Heating of Passive Implants

Numerical simulations can be adopted to aid the evaluation of the interaction between switched gradient fields and metallic implants and estimate the possible temperature increase. Anyway, an analysis of the consistency of their prediction with experiments is lacking, differently from what can be found for exposure to radiofrequency fields. The purpose of this work is to fill this gap.

A systematic comparison between experiments and simulations was conducted, considering commercial metallic orthopedic implants. The complexity of the exposure scenario was gradually increased, starting from the conditions defined in the ISO/TS 10974:2018 standard and moving to more realistic exposure scenarios with sinusoidal or pulsed gradient fields.

The computational tools demonstrated an overall good capability in predicting the outcomes of the experimental tests, as long as numerical simulations are properly set up (building of the virtual model, discretization parameters, positioning/orientation of the object). The consistency between simulations and measurements is comparable with the one obtainable under radiofrequency exposure and decreases with exposure complexity.

The results pave the way for the use of numerical simulations to support laboratory testing of passive implants heating under time-varying gradient fields.