Built-in RF safety for active implants: Harnessing impedance measurements from a commercial deep brain stimulator

Motivation: MRI of neurostimulators is severely constrained due to RF safety concerns. Goal(s): Demonstrate that built-in sensors in commercial devices, such as a deep brain stimulator, can provide all necessary information to detect and improve RF safety. Approach: We investigated and utilized built-in impedance measurements of two commercial DBS systems for the detection and mitigation of RF-induced currents on the electrodes of a DBS lead. Results: Impedance measurements were correlated at various RF power levels. Temperature rise at the tip of DBS electrodes could be reduced to 0.02 K from 17.14 K at the same total powers (16.85±0.45 W). Impact: Our demonstration of mitigation of RF-induced heating in active implants through built-in sensor measurements from a commercial DBS system indicated up to ~850× improvement in temperature rise proving the unmet value of sensors for MR imaging patients with active implants.