title: Evaluation of Perihilar Biliary Strictures: Does DWI Provide Additional Value to Conventional MRI?
abstract: OBJECTIVE
  The purpose of this study is to evaluate whether DWI provides additional value to conventional MRI with MRCP (MRI-MRCP) in the characterization of perihilar biliary strictures and in the evaluation of the longitudinal extent of perihilar cholangiocarcinomas.
  
  
  METHODS
  One hundred fourteen patients with perihilar strictures (81 malignant and 33 benign) underwent gadobutrol-enhanced MRI-MRCP and DWI using 10 b values (0-1000 s/mm(2)). Two readers independently reviewed a conventional set of MRI-MRCP images and a combined set of MRI-MRCP and DW images and scored the likelihoods of malignancy for perihilar strictures and involvement of the bilateral secondary confluence in malignant cases on a 5-point scale. The diagnostic performance of the two imaging sets was compared using ROC analysis.
  
  
  RESULTS
  In the characterization of 114 perihilar strictures, the addition of DWI showed no statistically significant improvement in diagnostic performance (reader 1, area under the ROC curve (Az) = 0.947 vs 0.923; reader 2, Az = 0.930 vs 0.905; all p > 0.05) with an interobserver agreement of κ = 0.763-0.818. In determining bilateral secondary confluence involvement for the 81 surgically confirmed malignant strictures, the conventional and combined sets showed no statistically significant difference in diagnostic performance (reader 1, Az = 0.820 vs 0.868; reader 2, Az = 0.826 vs 0.829; all p > 0.05), with κ = 0.564-0.588.
  
  
  CONCLUSIONS
  The addition of DWI to conventional MRI-MRCP did not improve diagnostic performance in the characterization of perihilar strictures or in determining whether the bilateral secondary biliary confluence was involved in perihilar cholangiocarcinomas.
authors.affiliation: 1 Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.
authors.forename: Kyu Sung
authors.initials: KS
authors.lastname: Choi
authors.affiliation: 1 Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.|2 Institute of Radiation Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: 1 Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.
authors.forename: Ijin
authors.initials: I
authors.lastname: Joo
authors.affiliation: 1 Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.|2 Institute of Radiation Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.affiliation: 1 Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.|2 Institute of Radiation Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D049448:Cholangiopancreatography, Magnetic Resonance; D002779:Cholestasis / Q000175:diagnosis*; D003251:Constriction, Pathologic / Q000175:diagnosis; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
keywords: DWI; MRI; characterization; cholangiocarcinoma; longitudinal tumor extent