Modifying surgical implantation of deep brain stimulation leads significantly reduces RF-induced heating during 3 T MRI: How Insights from Computational Modelings Improved Surgical Practice

Deep brain stimulation (DBS) is a neurosurgical procedure that involves implanting a pulse generator in patient's chest to send electric pulses via subcutaneous leads to electrodes implanted in nuclei deep within the brain to modulate aberrant neural behavior. DBS is the gold standard treatment for drug resistant Parkinson's disease, and its applications are rapidly expanding for other neurologic and psychiatric disorders. It is estimated that 70% of patients with DBS implants will need to undergo magnetic resonance imaging (MRI) exams during their lifetime. Unfortunately, however, access to MRI is restricted to DBS patients due to safety risks associated with radiofrequency (RF) heating of implanted leads. The major risk is due to the antenna effect , where the electric field of MRI transmitter couples with long DBS leads and amplifies the specific absorption rate (SAR) of radiofrequency energy in the tissue surrounding tips of implanted leads. The resultant RF heating is highly patient specific: up to 2 orders of magnitude difference has been observed in temperature rise in the tissue around individual DBS leads (0.1°C to 20°C) depending on the specific lead trajectory and patient's body composition [2].