title: Pancreas: optimal scan delay for contrast-enhanced multi-detector row CT.
abstract: OBJECTIVE
  To prospectively determine optimal scan delays for multiphasic contrast medium-enhanced imaging of the pancreas with multi-detector row computed tomography (CT).
  
  
  METHODS
  This study was approved by an institutional review committee, and patients gave written informed consent. One hundred ninety-one patients underwent three-phase CT of the pancreas after receiving intravenous contrast medium with a fixed duration injection of 30 seconds. Patients were prospectively assigned among four groups with scan delays of 25, 45, and 65 seconds (group 1); 30, 50, and 70 seconds (group 2); 35, 55, and 75 seconds (group 3); and 40, 60, and 80 seconds (group 4). Mean CT numbers of abdominal aorta, spleen, pancreatic parenchyma, superior mesenteric artery and vein, splenic vein, and hepatic parenchyma were measured, and increases in contrast enhancement on enhanced images were assessed. Qualitative analysis was performed with a four-point scale.
  
  
  RESULTS
  Abdominal aorta and superior mesenteric artery enhanced at a mean of 35 seconds from the start of injection (both P < .001). Pancreatic parenchyma enhanced most intensely at 35-45 seconds (P < .001) with a peak enhancement at the mean of 40 seconds. Liver parenchyma enhanced most intensely at 55-65 seconds with a peak at 60 seconds (P < .001). The mean time to peak enhancement was 45 seconds for the splenic vein and 55 seconds for the superior mesenteric vein. Qualitative results were in good agreement with quantitative results (both P < .001).
  
  
  CONCLUSIONS
  With the injection protocol used in this study, optimal scan delays for imaging the pancreas were 30-35 seconds for the abdominal aorta and the superior mesenteric artery, 35-45 seconds for the pancreas, 45 seconds for the splenic vein, and 55 seconds or later for the liver.
authors.affiliation: Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Goshima
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanematsu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kondo
authors.forename: Ryujiro
authors.initials: R
authors.lastname: Yokoyama
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kato
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsuge
authors.forename: Yoshimune
authors.initials: Y
authors.lastname: Shiratori
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hoshi
authors.forename: Minoru
authors.initials: M
authors.lastname: Onozuka
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Moriyama
authors.forename: Kyongtae T
authors.initials: KT
authors.lastname: Bae
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging; D008875:Middle Aged; D010179:Pancreas / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011856:Radiographic Image Enhancement / Q000379:methods; D013162:Splenic Vein / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media