title: Gadolinium-enhanced MR imaging of the liver: optimizing imaging delay for hepatic arterial and portal venous phases--a prospective randomized study in patients with chronic liver damage.
abstract: OBJECTIVE
  To investigate the optimal imaging delays for hepatic arterial and portal venous phases of gadolinium-enhanced dynamic spoiled gradient-recalled-echo magnetic resonance (MR) imaging of the liver in patients with chronic liver damage.
  
  
  METHODS
  MR images were obtained after intravenous bolus injection of gadopentetate dimeglumine in 100 patients with chronic liver damage. Test bolus imaging was performed to determine the aortic transit time. A 26-second spoiled gradient-recalled-echo sequence was used. Patients were randomized into four groups so that the middle of k space was acquired at 5, 10, 15, and 20 seconds for the first phase and 45, 50, 55, and 60 seconds for the second phase, respectively, from the time of arrival of contrast material in the abdominal aorta. Mean signal intensities of the liver, spleen, and abdominal aorta were measured, and images were reviewed prospectively by three radiologists in consensus. Analysis of variance, the Scheffé criterion for continuous data, and the Kruskal-Wallis test for categorical data were used for statistical evaluation.
  
  
  RESULTS
  Intense splenic enhancement with the moiré pattern without intense hepatic enhancement occurred at 10-15 seconds. Aortic and splenic enhancement significantly decreased from 45 to 50 seconds (P <.05). Spleen-to-liver contrast-to-noise ratio began to decrease at 20 seconds and decreased constantly over time. Qualitative results correlated well with quantitative results.
  
  
  CONCLUSIONS
  Biphasic imaging with k space centered at 10-15 and 50 seconds or later after arrival of contrast material in the abdominal aorta may be the optimal technique to obtain ideal contrast enhancement. Empirically, delays of 28-34 and 68 seconds or later after initiating contrast material injection may be effective for biphasic imaging.
authors.affiliation: Department of Radiology, Gifu University School of Medicine, Japan. masa-gif@umin.ac.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanematsu
authors.forename: Richard C
authors.initials: RC
authors.lastname: Semelka
authors.forename: Masayuki
authors.initials: M
authors.lastname: Matsuo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kondo
authors.forename: Mayumi
authors.initials: M
authors.lastname: Enya
authors.forename: Satoshi
authors.initials: S
authors.lastname: Goshima
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Moriyama
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hoshi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000493:pharmacokinetics*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006499:Hepatic Artery; D019694:Hepatitis B, Chronic / Q000097:blood / Q000175:diagnosis*; D019698:Hepatitis C, Chronic / Q000097:blood / Q000175:diagnosis*; D006519:Hepatitis, Alcoholic / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007275:Injections, Intravenous; D008103:Liver Cirrhosis / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA