RF-Induced Heating of Deep Brain Stimulation Devices During MRI: A Comparison Study of 1.5 T and 3 T Systems

High-field MRI systems (3 T and above) are widely used in clinical and research settings due to their high signal-to-noise ratio (SNR) and superior spatial resolution, enabling detailed anatomical visualization and enhanced diagnostic accuracy. When combined with invasive neuromodulation therapies such as deep brain stimulation (DBS), high-field MRI provides critical insights into treatment optimization and outcome interpretation. However, concerns about radio-frequency (RF) heating of implants have limited the routine use of 3 T MRI for many DBS patients. This heating risk arises from resonance effects, where specific implant configurations and lead lengths can amplify the MRI's electric fields, underscoring the importance of precise modeling and experimental validation of RF-induced heating under diverse conditions. In this work, we present a comprehensive evaluation of RF heating in a commercial DBS device during 1.5 T and 3 T MRI. Specifically, we measured and validated the transfer function of both a lead-only and a fully implanted DBS system under RF exposure at 64 MHz and 123 MHz, following FDA-recommended protocols outlined in ISO-TS 10974. Our results show that, while RF heating could still reach dangerous levels at 3 T, its magnitude was consistently and substantially lower compared to 1.5 T when the input power of the pulse sequences was adjusted to achieve the maximum allowable <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$B_{1}^{+}$</tex> at both field strengths (i.e., <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4.9 \mu ~\mathrm{T}$</tex> at 1.5 T and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.82 \mu ~\mathrm{T}$</tex> at 3 T). Post-MRI assessments revealed no device malfunction following 3 T scans. These findings are consistent with prior studies, calling into question the assumption that higher-field MRI necessarily poses greater risk for patients with implants.