New MRI-safe implant electrode design

Abstract

Medical implants often prevent patients having Magnetic Resonance Imaging (MRI) scans because the leads behave as antennas with respect to the RF excitation and cause hazardous heating in neural tissue. This manuscript describes an approach that virtually eliminates the risk of RF heating by means of easily-incorporated, mutually-coupled filars. The resulting leads need be neither physically larger nor significantly more costly than existing designs. Combined with thin insulation and surface roughening techniques, this manuscript represents the first complete release of recently-patented technologies. Both simulations and measurements at 128MHz are presented to confirm performance in 3-Tesla MRI machines.

A Novel Implant Electrode Design Safe in the RF Field of MRI Scanners

“…Currently, there are no DBS products available that offer any MRI compatibility. This manuscript introduces a new technique to improve the RF safety of implants in MRI machines and is an expansion of [16]. The technique, termed "decoy", requires as little as a single extra filar to be incorporated externally along the implant lead.…”

“…The technique, termed "decoy", requires as little as a single extra filar to be incorporated externally along the implant lead. It works by means of mutual coupling to an added filar of selected length and with thin insulation [6], [7], [16], [17]. When combined with resistive materials [6], [7] and surface treatments [18], it is expected to achieve superior MRI-safe performance with minimal scanning restrictions.…”

“…The approach is explored in detail in section III. In section IV we expand upon the single electrode work from [16] to include measurements on leads with multiple electrodes. We explore the impact of increasing the number of electrodes and demonstrate the effectiveness of adding decoy conductors to the lead.…”