Reduction of RF-heating on bilateral DBS leads using two channel RF-shimming on 3T MRI

Motivation: Bilateral deep brain stimulation (DBS) surgery would benefit from safe intraoperative 3T MRI using conventional scanners. Goal(s): Our goal was to develop a method to determine patient-specific safety constraints to scan a bilateral lead configuration with minimal RF-heating, by minimizing RF-induced currents at maximal B1. Approach: We scanned a phantom with two leads in different configurations, measured local heating and determined the transimpedance. Results: We could determine the phantom-specific safety constraints and find a low-SAR sequence meeting the constraints, after optimizing the two channel RF-shimming to minimize RF-heating by minimizing RF-induced currents at maximal B1. Impact: The proposed method can be used to minimize heating of a bilateral lead configuration and estimate patient-specific safety constraints, but further research has to be conducted to be able to use it during deep brain stimulation surgery.