title: Non-contrast-enhanced hepatic MR angiography: do two-dimensional parallel imaging and short tau inversion recovery methods shorten acquisition time without image quality deterioration?
abstract: OBJECTIVE
  To study whether shortening the acquisition time for selective hepatic artery visualization is feasible without image quality deterioration by adopting two-dimensional (2D) parallel imaging (PI) and short tau inversion recovery (STIR) methods.
  
  
  METHODS
  Twenty-four healthy volunteers were enrolled. 3D true steady-state free-precession imaging with a time spatial labeling inversion pulse was conducted using 1D or 2D-PI and fat suppression by chemical shift selective (CHESS) or STIR methods. Three groups of different scan conditions were assigned and compared: group A (1D-PI factor 2 and CHESS), group B (2D-PI factor 2×2 and CHESS), and group C (2D-PI factor 2×2 and STIR). The artery-to-liver contrast was quantified, and the quality of artery visualization and overall image quality were scored.
  
  
  RESULTS
  The mean scan time was 9.5±1.0 min (mean±standard deviation), 5.9±0.8 min, and 5.8±0.5 min in groups A, B, and C, respectively, and was significantly shorter in groups B and C than in group A (P<0.01). The artery-to-liver contrast was significantly better in group C than in groups A and B (P<0.01). The scores for artery visualization and overall image quality were worse in group B than in groups A and C. The differences were statistically significant (P<0.05) regarding the arterial branches of segments 4 and 8. Between group A and group C, which had similar scores, there were no statistically significant differences.
  
  
  CONCLUSIONS
  Shortening the acquisition time for selective hepatic artery visualization was feasible without deterioration of the image quality by the combination of 2D-PI and STIR methods. It will facilitate using non-contrast-enhanced MRA in clinical practice.
authors: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University, Graduate School of Medicine, Sakyo-ku, Kyoto, Japan. kotaro@kuhp.kyoto-u.ac.jp
authors: Kotaro
authors: K
authors: Shimada
authors: Hiroyoshi
authors: H
authors: Isoda
authors: Tomohisa
authors: T
authors: Okada
authors: Toshikazu
authors: T
authors: Kamae
authors: Shigeki
authors: S
authors: Arizono
authors: Yuusuke
authors: Y
authors: Hirokawa
authors: Toshiya
authors: T
authors: Shibata
authors: Kaori
authors: K
authors: Togashi
mesh_terms: D000328:Adult; D000465:Algorithms; D003287:Contrast Media; D005260:Female; D006499:Hepatic Artery / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media