title: Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid as an intrabiliary contrast agent: preliminary assessment.
abstract: OBJECTIVE
  We assessed the added efficacy of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (gadolinium-EOB) in depicting biliary structures compared with T2-weighted MR cholangiopancreatography (T2-MRCP) and measured reviewer preference and willingness-to-pay for the added value of biliary contrast.
  
  
  METHODS
  Ten patients prospectively underwent T2-MRCP and gadolinium-EOB-enhanced MR cholangiography (EOB-MRC). Three radiologists reviewed the unpaired, then the paired, examinations, rating biliary visualization using a 5-point scale. The common bile, right and left hepatic ducts, and second-order branches were evaluated. Improved biliary visualization using paired over unpaired tests indicated the added value of contrast media. Kappa values measured interobserver reliability. A regression model controlling for fixed effects due to reviewer and subject correlation quantified improvement in ratings attributable to paired review.
  
  
  RESULTS
  Average visualization ratings for unpaired review of EOB-MRC were the following: common bile duct, 3.3; right hepatic duct, 2.7; left hepatic duct, 2.5; second-order branches, 1.4. Average visualization ratings for unpaired review of T2-MCRP were the following: common bile duct, 3.4; right hepatic duct, 1.8; left hepatic duct, 2.2; second-order branches, 0.9. Ratings improved using paired tests over EOB-MRC and T2-MRCP for all structures (p < 0.001) except for T2-MRCP common bile duct ratings (p > 0.05). Agreement was moderate to good except for EOB-MRC common bile duct ratings. Paired review improved ratings (chi(2) < 0.0001) over T2-MRCP alone by 1.05 and over EOB-MRC alone by 0.68. Despite significant improvement, reviewers preferred unpaired T2-MRCP (53%) over unpaired EOB-MRC (17%) or paired tests (30%). Reviewers were willing to pay $25 (median) for gadolinium-EOB.
  
  
  CONCLUSIONS
  Combining T2-MRCP and EOB-MRC significantly improved biliary visualization over each test alone. However, improvement was small, and the perceived added value of gadolinium-EOB was modest.
authors.affiliation: Department of Radiology, MRI Section, University of Michigan Medical Center, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-0300, USA.
authors.forename: Ruth C
authors.initials: RC
authors.lastname: Carlos
authors.forename: Hero K
authors.initials: HK
authors.lastname: Hussain
authors.forename: Julie H
authors.initials: JH
authors.lastname: Song
authors.forename: Isaac R
authors.initials: IR
authors.lastname: Francis
mesh_terms: D000328:Adult; D000368:Aged; D001649:Bile Duct Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D002758:Cholangiography; D003258:Consumer Behavior; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA