Intraoperative Neurophysiological Monitoring During MRI-Guided Procedures: RF-Heating Risk Considerations

Abstract

Motivation: Neuromonitoring is critical during interventions near nerves. During MRI-guided interventions, a conventional system using metallic electrode needles has been used clinically, since MRI-conditional neuromonitoring systems are currently unavailable. This introduces elevated RF-heating risk. Goal(s): To identify factors that contribute to RF-heating of neuromonitoring electrodes and strategies to mitigate the risk. Approach: Neuromonitoring electrodes were inserted into porcine tissue and imaged with various clinically relevant MRI sequences for various neuromonitoring equipment configurations with high RF-heating risks. Temperatures were recorded using fiber-optic sensors. Results: Substantial temperature elevations were observed during MRI, and several RF-heating mitigation strategies were identified to enable neuromonitoring during MRI-guided procedures. Impact: The identified electrode RF-heating mitigation strategies can significantly reduce the RF-heating risk during MRI-guided ablations where neuromonitoring is critical. Understanding factors affecting RF-heating can also help identify high-risk procedures and guide risk-benefit analysis.