Assessing RF-Induced Heating of Active Implantable Medical Devices Near Orthopedic Implants During 1.5 T MRI

Existing methods for evaluating radiofrequency (RF)-induced heating typically assess active implantable medical devices (AIMDs) in isolation, without accounting for interactions with surrounding passive implants. This oversight can lead to under- or overestimation of heating in clinical scenarios involving multiple implants. This article presents an efficient approach for assessing RF-induced heating of AIMDs in a magnetic resonance imaging (MRI) environment when other implantable medical devices are present. The method leverages the transfer function approach to evaluate heating effects. To demonstrate its effectiveness, in vitro simulations and experiments were conducted using a cervical plate at various configurations. RF-induced heating within a human body model was then analyzed for an AIMD with and without nearby implantable devices. The results show that RF-induced heating at the lead tip varied by up to 36.7%, depending on the type and location of nearby passive implants. These findings highlight the critical need to incorporate multi-implant interactions into RF safety assessments to achieve more accurate and clinically relevant predictions.