title: Determining the optimal timing for early arterial phase hepatic CT imaging by measuring abdominal aortic enhancement in variable contrast injection protocols.
abstract: OBJECTIVE
  To find the optimal scan timing for early arterial phase hepatic CT with adequate arterial enhancement after the aortic contrast arrival.
  
  
  METHODS
  Sixty patients were divided randomly into three groups, each of which received 2.0 mL/kg of the 300 mgI/mL contrast medium with an injection duration of 30 seconds (Group A, mean rate 3.6 mL/sec); of 25 seconds (B, 4.6 mL/sec); of 30 seconds (3.6 mL/sec) followed by a saline chaser (C).
  
  
  RESULTS
  After the contrast arrival, aortic enhancement increased rapidly for 6-15 seconds (mean, 10 seconds) to the initial peak enhancement in all groups, and then, increased moderately to the maximum aortic enhancement over the following 19, 13, and 21 seconds, respectively. The mean maximum aortic enhancement in Group B (392 HU) and C (360 HU) were significantly higher than that in A (326 HU), respectively. The difference between the initial and maximum aortic enhancement was less than 50 HU.
  
  
  CONCLUSIONS
  The optimal timing of the early arterial phase for hepatic CT arteriography is 10-15 seconds after the aortic arrival.
authors.affiliation: Department of Radiology, Osaka University Graduate School of Medicine, Osaka, Japan. murakami@med.kindai.ac.jp
authors.forename: Takamichi
authors.initials: T
authors.lastname: Murakami
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Onishi
authors.forename: Koji
authors.initials: K
authors.lastname: Mikami
authors.forename: Riccardo
authors.initials: R
authors.lastname: Iannaccone
authors.forename: Michael P
authors.initials: MP
authors.lastname: Federle
authors.forename: Tonsok
authors.initials: T
authors.lastname: Kim
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hori
authors.forename: Atsuya
authors.initials: A
authors.lastname: Okada
authors.forename: Taro
authors.initials: T
authors.lastname: Marukawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Higashihara
authors.forename: Roberto
authors.initials: R
authors.lastname: Passariello
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008107:Liver Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D013997:Time Factors
chemical_list: D003287:Contrast Media