Effect of Implantable Pulse Generator (IPG) Impedance on the MRI Conditionality of AIMDs under 1.5T MRI

The replacement of an implantable pulse generator (IPG) is necessary when its battery reaches the end of its lifespan or in cases of malfunction. For optimal MRI safety, replacing the IPG with the exact model is preferred. However, when an identical model is unavailable, assessing the degree of interchangeability among different IPGs and their impact on MRI safety is essential. This study investigates the influence of IPG input impedance on RF-induced voltage at the IPG and heating at the electrode tip, key factors determining IPG interchangeability when using the same leads. The findings indicate that changes in IPG impedance affect both electrode heating and induced voltage at the IPG. However, electrode heating is influenced by the impedance ratio between the lead and IPG, whereas the induced voltage mainly depends on the IPG input impedance. These insights contribute to a better understanding of IPG safety and performance variations in MRI environments.