title: Whole-heart coronary MR angiography under a single breath-hold: a comparative study with respiratory-gated acquisition using a multi-element phased-array coil.
abstract: OBJECTIVE
  To compare visualization using whole-heart coronary magnetic resonance angiography (CMRA) acquired during a single breath-hold (BH) with that using conventional respiratory-gated (RG) CMRA.
  
  
  METHODS
  The CMRAs of 14 healthy subjects under either BH or RG conditions were studied using a 1.5 T system equipped with a whole-body phased-array coil and 16-channel receivers. The BH examination was accelerated using parallel imaging (PI) by factors of 2.5 and 2 in the phase and section directions, respectively. For the RG examination, a PI factor of 2 was used only in the phase direction. The visualization quality of 15 coronary segments using each condition was evaluated with a five-point scale (0-4). Differences between two conditions were compared at segments with an average score greater than 2 in RG-CMRA.
  
  
  RESULTS
  The average examination time for BH and RG acquisition scans was 34 s and 11 min 31 s, respectively. Ten segments (segments 1-3, 5-9, 11, and 13) had average scores higher than 2 in RG-CMRA. Of these, BH-CMRA had significantly lower scores than RG-CMRA at six segments (segments 1, 5-8, and 11) after correction for multiple comparisons (p<0.005). However, in BH-CMRA, proximal segments (segments 1-2, 5-7, and 11) showed average scores over 2, indicating marginally acceptable image quality.
  
  
  CONCLUSIONS
  Compared with the relatively limited degree of image degradation with RG-CMRA, the present data suggest that BH-CMRA would be useful for screening and as an adjunct to RG-CMRA that is occasionally incomplete.
authors.affiliation: Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Sakyoku, Kyoto, Japan. tomokada@kuhp.kyoto-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Okada
authors.forename: S
authors.initials: S
authors.lastname: Kanao
authors.forename: S
authors.initials: S
authors.lastname: Kuhara
authors.forename: A
authors.initials: A
authors.lastname: Ninomiya
authors.forename: K
authors.initials: K
authors.lastname: Fujimoto
authors.forename: A
authors.initials: A
authors.lastname: Kido
authors.forename: K
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D017023:Coronary Angiography / Q000295:instrumentation / Q000379:methods; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods; D008297:Male; D019047:Phantoms, Imaging; D012119:Respiration