Keeping a Low (Temperature) Profile: An Analysis of In Vivo RF Heating of Vagus Nerve Stimulation Devices in Low (0.55 T) vs. High-Field (1.5 T) MRI

Motivation: The growing accessibility of low-field MRI systems and the lack of scanning guidelines for VNS devices in these systems highlight a need to assess RF heating risks. Goal(s): To compare the predicted RF-induced heating of a VNS device at 0.55 T and 1.5 T MRI, providing insights for safe scanning practices. Approach: We measured the transfer function of a commercial VNS device and used it to simulate in vivo heating at 0.55 T and 1.5 T, varying landmark and B1+ values. Results: Predictions suggest that RF heating at 0.55 T can be comparable to that at 1.5 T. Impact: This study challenges the common belief that low-field MRI is inherently safer for patients with implants, demonstrating that RF heating at 0.55 T can be similar to or exceed that at 1.5 T, underscoring the need for careful patient assessment.