Application of Surgical Lead Management and Reconfigurable Coil Technology to Reduce RF Heating of DBS Implants during MRI at 3T Under Variant Body Compositions

Abstract

Patients with active implants such as deep brain stimulation (DBS) devices, have limited access to magnetic resonance imaging (MRI) due to risks of RF heating. With an aging population, the prevalence of neurodegenerative and vascular disease increases; and so does the indication for MRI exams in patients with such implants. In response to this growing need for MRI, many groups have investigated strategies to mitigate the RF heating of the implants. These efforts, however, have relied either on simulations with homogenous body models or simplified phantom experiments (box shaped phantom with single tissue). It is well established, however, that the shape and heterogeneity of human body affects the distribution of MRI electric fields, which by proxy, alters the RF heating of an implant inside the body. In this contribution, we applied numerical simulations and phantom experiments to examine the effectiveness of RF heating mitigation strategies under variant patient body compositions, focusing on two recently proposed techniques: (a) surgical modification of DBS lead trajectories inside the body, and (b) use of a patient-adjustable reconfigurable MRI coil, both aiming to reduce the coupling of implanted leads and MRI electric fields. Our results demonstrated that both techniques perform well under variant body compositions.Index Terms-Body model, implant safety, finite element, magnetic resonance imaging (MRI), RF heating, simulation, specific absorption rate (SAR), transmit coil. J. Rosenow is with

Computational Investigation of the Factors That Affect Tangential Electric Fields along Cardiac Lead Paths inside MRI Birdcage Coils

“…Therefore, because of the high degree of complexity during the interaction between the MRI coil and the implant, the results of previous works measured in homogenous phantoms might not provide enough confidence regarding patients' safety as the patient's body composition alters the RF power deposition in the tissue surrounding implanted leads [18][19][20][21][22][23]. In [24], the RF-induced electric field inside a homogenous phantom was assessed, demonstrating a different spatial distribution compared to the respective distribution inside a human model [25].…”