title: Superconducting open-configuration MR imaging system for image-guided therapy.
abstract: OBJECTIVE
  To develop a superconducting magnetic resonance (MR) imager that provides direct access to the patient and permits interactive MR-guided interventional procedures.
  
  
  METHODS
  A 0.5-T superconducting magnet that allows a region of vertical access to the patient was designed and constructed. This magnet was integrated with newly designed shielded gradient coils, flexible surface coils, and nonmagnetic displays and with position-monitoring probes and device-tracking instrumentation.
  
  
  RESULTS
  The magnet homogeneity was 12.3 ppm, and the gradient field was linear to within 1% over an imaging region 30 cm in diameter. The signal-to-noise ratio was 10% higher than in a comparable 0.5-T superconducting imager. Images were obtained in several anatomic regions with use of routine pulse sequences. Interactive image plane selection and near real-time imaging, with use of fast gradient-recalled echo sequences, were demonstrated at a rate of one image every 1.5 seconds.
  
  
  CONCLUSIONS
  MR-guided interventional procedures can be performed with full patient access with use of an open-configuration, superconducting MR magnet with near real-time imaging and interactive image plane control.
authors.affiliation: General Electric Corporate Research and Development Center, General Electric Co, Schenectady, NY 12309, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Schenck
authors.forename: F A
authors.initials: FA
authors.lastname: Jolesz
authors.forename: P B
authors.initials: PB
authors.lastname: Roemer
authors.forename: H E
authors.initials: HE
authors.lastname: Cline
authors.forename: W E
authors.initials: WE
authors.lastname: Lorensen
authors.forename: R
authors.initials: R
authors.lastname: Kikinis
authors.forename: S G
authors.initials: SG
authors.lastname: Silverman
authors.forename: C J
authors.initials: CJ
authors.lastname: Hardy
authors.forename: W D
authors.initials: WD
authors.lastname: Barber
authors.forename: E T
authors.initials: ET
authors.lastname: Laskaris
mesh_terms: D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods