title: Determination of optimal time window for liver scanning with CT during arterial portography.
abstract: OBJECTIVE
  To determine the optimal time window for scanning the liver with computed tomography (CT) during arterial portography (CTAP).
  
  
  METHODS
  After vasodilation and contrast medium injection into the superior mesenteric artery (80 mL at 5 mL/sec), 25 repeated scans were obtained at a single level within 83 seconds in 13 patients. Attenuation was measured on every scan, and time-attenuation curves were created. Enhancement characteristics of the portal vein, liver parenchyma, aorta, and tumors were evaluated.
  
  
  RESULTS
  Parenchymal enhancement of more than 60 HU was achieved between 18 seconds +/- 4 (standard deviation) and 67 seconds +/- 15, and high parenchyma-to-tumor contrast of more than 50 HU occurred between 18 seconds +/- 3 and 62 seconds +/- 14.
  
  
  CONCLUSIONS
  To scan the liver within such a narrow time window, a spiral CT technique is necessary. When the above injection parameters are used in CTAP, the spiral CT sequence should be started 20 seconds after the beginning of the injection.
authors.affiliation: Department of Radiology, University of Vienna, Austria.
authors.forename: O
authors.initials: O
authors.lastname: Graf
authors.forename: W I
authors.initials: WI
authors.lastname: Dock
authors.forename: J
authors.initials: J
authors.lastname: Lammer
authors.forename: S
authors.initials: S
authors.lastname: Thurnher
authors.forename: K L
authors.initials: KL
authors.lastname: Eibenberger
authors.forename: R
authors.initials: R
authors.lastname: Wildling
authors.forename: B
authors.initials: B
authors.lastname: Niederle
authors.forename: E K
authors.initials: EK
authors.lastname: Lang
authors.forename: G
authors.initials: G
authors.lastname: Lechner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007269:Injections, Intra-Arterial; D007479:Iopamidol / Q000008:administration & dosage; D008099:Liver / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000000981:diagnostic imaging; D011172:Portography; D014057:Tomography, X-Ray Computed
chemical_list: D007479:Iopamidol