Analyzing localized heating in Deep Brain Stimulation leads under radiofrequency exposure

Abstract

MRI is widely used in medical diagnostics due to its superior tissue contrast. However, patients with active implantable medical devices (AIMDs), such as deep brain stimulation (DBS) systems, face risks during MRI. DBS is an AIMD commonly used for neurological conditions, and many patients require MRI scans. During MRI, radiofrequency (RF) field energy can couple with the conductive DBS lead, increasing the specific absorption rate (SAR) of RF energy in surrounding tissues. This interaction may cause localized heating at the electrode tip, posing a safety concern. Heating depends on the shape, orientation, and length of the leads, and configuring the extracranial portion of DBS leads into concentric loops near the lead insertion point has been shown to reduce heating. In this study, realistic lead trajectories with and without loops were modeled to assess their impact on RF heating by minimizing exposure to the maximum tangential electric field. Using the validated transfer function of a commercially available Boston Scientific DBS system, tangential electric fields calculated in ANSYS HFSS along the lead trajectories were used to predict RF heating at the electrode tip. This work highlights the importance of optimizing DBS trajectories to significantly reduce RF heating and enhance patient safety