Reducing RF-Induced Heating of DBS in 3 T MRI Using Dual-Role Receive Arrays as Wireless Resonators: A Simulation Study

Abstract

Magnetic resonance imaging (MRI) scanning remains largely restricted to specific modalities, typically involving low radiofrequency (RF) power levels and stringent protocols for patients with deep brain stimulation (DBS) implants, due to safety concerns related to RF-induced heating of the implants. A 6-channel dual-role head coil array capable of modulating the electric-field (E-field) distribution was designed and evaluated using electromagnetic (EM) simulations. By optimizing the resonant frequency of each coil element during RF transmission, the transmit field was reshaped, leading to a significant reduction in RF-induced heating near the DBS lead tip. The proposed method was validated across two scenarios of increasing complexity: 1) a simple straight conductive wire for concept validation and 2) four realistic DBS leads representing complex real-world scenarios. The coil settings can be optimized either to suppress the E-field at a specific location, such as the DBS lead tip, or to suppress the peak specific absorption rate (SAR) across the entire human head. For location-specific E-field suppression, the simplified predefined-state control scheme and the fine-tuning genetic algorithm (GA)-based framework were implemented, achieving E-field reductions of 45.9% and 68.3%, respectively. For whole-head peak SAR suppression, the annealed Log-Sum-Exp (LSE)–Adaptive Moment Estimation (Adam) framework (LSE–Adam) was implemented, achieving an average 1 g SAR reduction of 72.09% across four realistic DBS lead models. The dual-role coil demonstrated a high degree of flexibility in controlling the transmit field and reducing RF-induced heating at DBS implants, offering a novel approach to mitigate RF-induced heating of the implants in MRI.