Effects of Implantable Pulse Generator (IPG) Impedance on the MRI Conditionality of Active Implantable Medical Devices (AIMDs) under 1.5T MRI

Motivation: To understand the interchangeability the IPGs for an AIMD system under MR RF exposure. Goal(s): To evaluate/compare the effect of AIMD input impedance on both the RF-induced heating and the RF-induced voltage under RF exposure. Approach: Evaluate the AIMD models for both RF-induced heating/voltage using an implantable lead connected to IPGs with different input impedances. The AIMD models (transfer functions) are evaluated via the reciprocity approach. Results: When the lead characteristic impedance and IPG impedance differ greatly, the device heating stays consistent. However, the induced voltage changes. Both RF-induced heating/voltage are crucial for the interchangeability of IPGs for an AIMD system. Impact: This study emphasizes the significance of on the RF-induced voltage at the IPG in addition to heating at the distal end. The analysis method presented could serve as a valuable approach for assessing the interchangeability of IPGs for AIMDs.