title: Evaluation of magnetic resonance imaging issues for a wirelessly powered lead used for epidural, spinal cord stimulation.
abstract: OBJECTIVE
  The objective of this investigation was to evaluate magnetic resonance imaging (MRI) issues (magnetic field interactions, MRI-related heating, and artifacts) for a wirelessly powered lead used for spinal cord stimulation (SCS).
  
  
  METHODS
  A newly developed, wirelessly powered lead (Freedom-4, Stimwave Technologies Inc., Scottsdale, AZ, USA) underwent evaluation for magnetic field interactions (translational attraction and torque) at 3 Tesla, MRI-related heating at 1.5 Tesla/64 MHz and 3 Tesla/128 MHz, and artifacts at 3 Tesla using standardized techniques. MRI-related heating tests were conducted by placing the lead in a gelled-saline-filled phantom and performing MRI procedures using relatively high levels of radiofrequency energy. Artifacts were characterized using T1-weighted, spin echo (SE), and gradient echo (GRE) pulse sequences.
  
  
  RESULTS
  The lead exhibited minor magnetic field interactions (2 degree deflection angle and no torque). Heating was not substantial under 1.5 Tesla/64 MHz (highest temperature change, 2.3°C) and 3 Tesla/128 MHz (highest temperature change, 2.2°C) MRI conditions. Artifacts were moderate in size relative to the size and shape of the lead.
  
  
  CONCLUSIONS
  These findings demonstrated that it is acceptable for a patient with this wirelessly powered lead used for SCS to undergo MRI under the conditions utilized in this investigation and according to other necessary guidelines. Artifacts seen on magnetic resonance images may pose possible problems if the area of interest is in the same area or close to this lead.
authors.affiliation: Keck School of Medicine, University of Southern California and Institute for Magnetic Resonance Safety, Education, and Research, Los Angeles, CA, USA.
authors.forename: Frank G
authors.initials: FG
authors.lastname: Shellock
authors.forename: Annabelle J
authors.initials: AJ
authors.lastname: Audet-Griffin
mesh_terms: D016477:Artifacts; D004559:Electric Wiring; D004824:Epidural Space / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D019047:Phantoms, Imaging; D013116:Spinal Cord / Q000502:physiology*; D062187:Spinal Cord Stimulation; D013696:Temperature
keywords: MRI; MRI safety; artifacts; implants; magnetic resonance imaging (MRI); spinal cord stimulation (SCS)