title: Truly hybrid X-ray/MR imaging: toward a streamlined clinical system.
abstract: OBJECTIVE
  We have installed an improved X-ray/MR (XMR) truly hybrid system with higher imaging signal-to-noise ratio (SNR) and versatility than our first prototype. In our XMR design, a fixed anode X-ray fluoroscopy system is positioned between the two donut-shaped magnetic poles of a 0.5T GE Signa-SP magnet (SP-XMR). This paper describes the methods for increased compatibility between the upgraded x-ray and MR systems that have helped improve patient management.
  
  
  METHODS
  A GE OEC 9800 system (GE OEC Salt Lake City, UT) was specially reconfigured for permitting X-ray fluoroscopy inside the interventional magnet. A higher power X-ray tube, a new permanent tube mounting system, automatic exposure control (AEC), remote controlled collimators, choice of multiple frame rates, DICOM image compatibility, magnetically shimmed X-ray detector, X-ray compatible MR coil, and better RF shielding are the highlights of the new system. A total of 23 clinical procedures have been conducted with SP-XMR guidance of which five were performed using the new system.
  
  
  RESULTS
  The 70% increased power for fluoroscopy, and a new 6 times higher power single frame imaging mode, has improved imaging capability. The choice of multiple imaging frame rates, AEC, and collimator control allow reduction in X-ray exposure to the patient. The DICOM formatting has permitted easy transfer of clinical images over the hospital PACS network. The increased MR compatibility of the detector and the X-ray transparent MR coil has enabled faster switching between X-ray and MR imaging modes.
  
  
  CONCLUSIONS
  The improvements introduced in our SP-XMR system have further streamlined X-ray/MR hybrid imaging. Additional clinical procedures could benefit from the new SP-XMR imaging.
authors.affiliation: Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305, USA. aganguly@stanford.edu
authors.forename: Arundhuti
authors.initials: A
authors.lastname: Ganguly
authors.forename: Zhifei
authors.initials: Z
authors.lastname: Wen
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Daniel
authors.forename: Kim
authors.initials: K
authors.lastname: Butts
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Kee
authors.forename: Viola
authors.initials: V
authors.lastname: Rieke
authors.forename: Huy M
authors.initials: HM
authors.lastname: Do
authors.forename: Norbert J
authors.initials: NJ
authors.lastname: Pelc
authors.forename: Rebecca
authors.initials: R
authors.lastname: Fahrig
mesh_terms: D004867:Equipment Design; D005471:Fluoroscopy / Q000295:instrumentation*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D019047:Phantoms, Imaging; D015641:Radiography, Interventional / Q000295:instrumentation*