title: Effect of varying contrast material iodine concentration and injection technique on the conspicuity of hepatocellular carcinoma during 64-section MDCT of patients with cirrhosis.
abstract: OBJECTIVE
  The aim of this study was to compare the intraindividual effects of contrast material with two different iodine concentrations on the conspicuity of hepatocellular carcinoma (HCC) and vascular and hepatic contrast enhancement during multiphasic, 64-section multidetector row CT (MDCT) in patients with cirrhosis using two contrast medium injection techniques.
  
  
  METHODS
  Patients were randomly assigned to one of two groups with an equal iodine dose but different contrast material injection techniques: scheme A, fixed injection duration (25 s), and scheme B, fixed injection flow rate (4 ml s(-1)). For each group, patients were randomised to receive both moderate-concentration contrast medium (MCCM) and high-concentration contrast medium (HCCM) during two CT examinations within 3 months. Enhancement of the aorta, liver and portal vein and the tumour-to-liver contrast-to-noise ratio (CNR) were compared between MCCM and HCCM.
  
  
  RESULTS
  30 patients (mean age 59 years; range 45-80 years; 16 patients in scheme A and 14 in scheme B) with a total of 31 confirmed HCC nodules were prospectively enrolled. For scheme B, the mean contrast enhancement of the aorta and tumour-to-liver CNR were significantly higher with HCCM than with MCCM during the hepatic arterial phase (+350.5 HU vs +301.1 HU, p = 0.001, and +7.5 HU vs +5.5 HU, p = 0.004). For both groups, there was no significant difference between MCCM and HCCM for all other comparisons.
  
  
  CONCLUSIONS
  For a constant injection flow rate, HCCM significantly improves the conspicuity of HCC lesions and aortic enhancement during the hepatic arterial phase on 64-section MDCT in patients with cirrhosis.
authors.affiliation: Department of Radiological Sciences, University of Rome Sapienza, Rome 00159, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Guerrisi
authors.forename: D
authors.initials: D
authors.lastname: Marin
authors.forename: R C
authors.initials: RC
authors.lastname: Nelson
authors.forename: G
authors.initials: G
authors.lastname: De Filippis
authors.forename: M
authors.initials: M
authors.lastname: Di Martino
authors.forename: H
authors.initials: H
authors.lastname: Barnhart
authors.forename: R
authors.initials: R
authors.lastname: Masciangelo
authors.forename: I
authors.initials: I
authors.lastname: Guerrisi
authors.forename: R
authors.initials: R
authors.lastname: Passariello
authors.forename: C
authors.initials: C
authors.lastname: Catalano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage / Q000737:chemistry; D018592:Cross-Over Studies; D006801:Humans; D007275:Injections, Intravenous; D007455:Iodine / Q000008:administration & dosage; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine