title: Whole-heart coronary magnetic resonance angiography with parallel imaging: comparison of acceleration in one-dimension vs. two-dimensions.
abstract: OBJECTIVE
  To evaluate visualization of the whole-heart coronary arteries accelerated with parallel imaging (PI) applied in two-dimension (2D) in comparison with one-dimension (1D).
  
  
  METHODS
  Seventeen healthy subjects were studied with a 1.5-T scanner equipped with a whole body phased array coil system and 16-channel receivers. Using 16 coil elements, whole-heart coronary magnetic resonance angiography (CMRA) was acquired in two conditions of 1D-PI and 2D-PI. The former scan was accelerated in phase direction by factor of 2 and the latter in phase and slice directions by factors of 2.5 and 2, respectively. Visualized length of right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LCX) was measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) was also measured. The CMRA quality was assessed in segment-wise with a five-point scale.
  
  
  RESULTS
  The average scan time decreased to 5.3+/-2.2 min in 2D-PI from 11.6+/-3.5 min in 1D-PI, reducing the scan time to 45%. The visualized length, SNR, and CNR in average were smaller for images of 2D-PI compared with those of 1D-PI, however, statistically significant results were observed only in RCA (P<0.05). Score reduction of 2D-PI image quality was limited to 0.34 in average, and only two out of fifteen segments (#2, 6) showed significant score deterioration (P<0.05).
  
  
  CONCLUSIONS
  Compared with the relatively limited degree of image degradation, 2D-PI offered a large reduction of the acquisition time, which is of large benefit in clinical situations.
authors.affiliation: Department of Diagnostic Radiology, Kyoto University, 54 Shogoin Kawaharacho, Sakyoku, Kyoto 606-8507, Japan. tomokada@kuhp.kyoto-u.ac.jp
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Okada
authors.forename: Shotaro
authors.initials: S
authors.lastname: Kanao
authors.forename: Ayako
authors.initials: A
authors.lastname: Ninomiya
authors.forename: Saori
authors.initials: S
authors.lastname: Sato
authors.forename: Shigehide
authors.initials: S
authors.lastname: Kuhara
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kamae
authors.forename: Kimio
authors.initials: K
authors.lastname: Gotoh
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000054:Acceleration; D000328:Adult; D017023:Coronary Angiography / Q000379:methods; D003331:Coronary Vessels / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male