In-Human Assessment of Radio Frequency Induced Heating for Implants during MRI

Abstract

Abstract Radio frequency induced heating of medical implants during magnetic resonance imaging (MRI) poses a serious threat to patient safety, and in vivo assessment of heating permits individualized on-site safety assessment. Based on the proton resonance frequency (PRF) thermometry, we developed a method for the in vivo evaluation of implant heating. It combined PRF signals around the implants with bioheat transfer law to reduce the interference of metal artifacts and to estimate the RF heating at implant surface. To apply this idea, we proposed a PRF-based test module consisting of processes of thermometry-heating-thermometry and verified its feasibility in phantom. Then, we validated this module for electrodes in the pig brain and investigated the effect of its parameters, as a result, the heating assessment could be achieved in approximately 2 min with a mean difference to probe measurement of 0.6 °C. Finally, we demonstrated the clinical translation in a patient with a conventional deep brain stimulation device and derived the individualized safe RF condition under 3.0T MRI. This study presents a practical solution for the in-human safety assessment of implants during MRI, which can be beneficial for both clinical and research purposes.