title: Cervical external immobilization devices: evaluation of magnetic resonance imaging issues at 3.0 Tesla.
abstract: METHODS
  Laboratory investigation, ex vivo.
  
  
  OBJECTIVE
  Currently, no studies have addressed the magnetic resonance imaging (MRI) issues for cervical external immobilization devices at 3-Tesla. Under certain conditions significant heating may occur, resulting in patient burns. Furthermore, artifacts can be substantial and prevent the diagnostic use of MRI. Therefore, the objective of this investigation was to evaluate MRI issues for 4 different cervical external immobilization devices at 3-Tesla.
  
  
  BACKGROUND
  Excessive heating and substantial artifacts are 2 potential complications associated with performing MRI at 3-Tesla in patients with cervical external immobilization devices. Using ex vivo testing techniques, MRI-related heating and artifacts were evaluated for 4 different cervical devices during MRI at 3-Tesla.
  
  
  METHODS
  Four cervical external immobilization devices (Generation 80, Resolve Ring and Superstructure, Resolve Ring and Jerome Vest/Jerome Superstructure, and the V1 Halo System; Ossur Americas, Aliso Viejo, CA) underwent MRI testing at 3-Tesla. All devices were made from nonmetallic or nonmagnetic materials. Heating was determined using a gelled-saline-filled skull phantom with fluoroptic thermometry probes attached to the skull pins. MRI was performed at 3-Tesla, using a high level of RF energy. Artifacts were assessed at 3-Tesla, using standard cervical imaging techniques.
  
  
  RESULTS
  The Generation 80 and V1 Halo devices exhibited substantial temperature rises (11.6 degrees C and 8.5 degrees C, respectively), with "sparking" evident for the Generation 80 during the MRI procedure. Artifacts were problematic for these devices, as well. By comparison, the 2 Resolve Ring-based cervical external immobilization devices showed little or no heating (< or = 0.6 degrees C) and the artifacts were acceptable for diagnostic MRI examinations.
  
  
  CONCLUSIONS
  The low degree of heating and minor artifacts associated with the Resolve-based cervical external immobilization devices indicated that these products are safe for patients undergoing MRI at 3-Tesla.
authors.affiliation: RadNet Management, Inc., Los Angeles, CA, USA.
authors.forename: Francis L
authors.initials: FL
authors.lastname: Diaz
authors.forename: Lisa
authors.initials: L
authors.lastname: Tweardy
authors.forename: Frank G
authors.initials: FG
authors.lastname: Shellock
mesh_terms: D016477:Artifacts; D002574:Cervical Vertebrae / Q000293:injuries / Q000473:pathology*; D004867:Equipment Design; D006358:Hot Temperature; D006801:Humans; D007103:Immobilization / Q000009:adverse effects / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000009:adverse effects / Q000295:instrumentation*; D008422:Materials Testing; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests