title: Effect of saline flush on enhancement of proximal and distal segments using 320-row coronary CT angiography.
abstract: OBJECTIVE
  To investigate the effect of saline flush on coronary CT angiography of proximal, middle, and distal coronary artery segments, using 320-row CT, and to compare two injection duration protocols as to amount of contrast in the right heart chambers.
  
  
  METHODS
  This retrospective study was approved by the local ethics committee, and the requirement for informed consent to participate in this study was waived. The final study group included 108 patients who underwent coronary CT angiography. The first 36 patients received contrast medium without saline flush (group 1); the next 36 patients received contrast medium for 14s and saline flush (group 2); the last 36 patients received contrast medium for 12s and saline flush (group 3). The CT number, noise, contrast-to-noise ratio (CNR), and number of segments with a CT number greater than 325 Hounsfield units (HU) were recorded for proximal, middle, and distal segments.
  
  
  RESULTS
  The CT numbers and the CNR in groups 2 and 3 were significantly higher than that in group 1 (p<0.005); the difference between groups 2 and 3 was not significant. The proportion of segments greater than 325HU improved with saline flush (p<0.05), with a larger improvement in the distal segments.
  
  
  CONCLUSIONS
  Saline flush improves enhancement and CNR of coronary arteries, particularly of distal segments, in coronary CT angiography using 320-row CT. An average contrast medium injection of 44mL was feasible using a saline flush.
authors.affiliation: Department of Radiology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. tomizawa-tky@umin.ac.jp
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tomizawa
authors.forename: Fumio
authors.initials: F
authors.lastname: Suzuki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Akahane
authors.forename: Rumiko
authors.initials: R
authors.lastname: Torigoe
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kiryu
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
mesh_terms: D000368:Aged; D003287:Contrast Media; D017023:Coronary Angiography / Q000706:statistics & numerical data*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000008:administration & dosage; D007564:Japan / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000008:administration & dosage; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
chemical_list: D003287:Contrast Media; D012965:Sodium Chloride; D007479:Iopamidol