MRI RF Safety of Active Implantable Medical Devices (AIMDs): Effect of Conductivity of Tissue Simulating Media on Device Model Accuracy

The Tier 3 procedure for testing electrically long active implantable medical devices (AIMDs) for MRI RF safety involves the development of transfer function models (TFMs) of the AIMDs. Accuracy of the TFM depends on how closely the TSM mimics the tissues in which the AIMD is implanted. We find that the conductivity of the medium surrounding the lead electrode has a strong influence on the transfer function magnitude of the DUT. Therefore, TFMs of the DUT developed in a TSM whose conductivity mimics that of the in-vivo tissue that surrounds the electrode under test results in the most accurate TFM.