title: Two-dimensional coronary MR angiography without breath holding.
abstract: OBJECTIVE
  To determine whether breath holding can be eliminated in two-dimensional magnetic resonance (MR) imaging of the coronary arteries by using real-time respiratory gating.
  
  
  METHODS
  Thirty-one subjects (20 healthy volunteers, 11 patients) underwent MR imaging. In 13 subjects, a respiratory monitoring belt was used, and in 18 subjects, a navigator echo was used. MR imaging was performed with breath holding, respiratory gating, and respiratory gating with two signals acquired. Three reviewers conducted a blinded review of the images, and overall image quality was rated on a scale from 1 (poor) to 5 (excellent).
  
  
  RESULTS
  Respiratory gating with two signals acquired provided image quality superior to that with breath-hold imaging (3.7 vs 3.0, respectively; P < .05). Measurements of signal-to-noise ratio (14.5 for respiratory gating with two signals acquired and 11.9 for breath holding) supported the results of the image review. Navigator-echo gating provided better image quality than the monitoring belt (3.7 vs 3.1, respectively; P < .05).
  
  
  CONCLUSIONS
  Breath holding may be eliminated by gating image acquisition to a real-time monitor of respiratory position. Respiratory gating enables improved resolution by means of acquisition of multiple signals, provides aligned sections of coronary arteries, and improves patient tolerance.
authors.affiliation: Frederik Philips Magnetic Resonance Research Center, Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: J N
authors.initials: JN
authors.lastname: Oshinski
authors.forename: L
authors.initials: L
authors.lastname: Hofland
authors.forename: S
authors.initials: S
authors.lastname: Mukundan
authors.forename: W T
authors.initials: WT
authors.lastname: Dixon
authors.forename: W J
authors.initials: WJ
authors.lastname: Parks
authors.forename: R I
authors.initials: RI
authors.lastname: Pettigrew
mesh_terms: D000328:Adult; D000368:Aged; D003331:Coronary Vessels; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008875:Middle Aged; D012119:Respiration