title: Diagnostic accuracy of magnetic resonance and endoscopic retrograde cholangiography in primary sclerosing cholangitis.
abstract: OBJECTIVE
  To evaluate the accuracy and interobserver variability of magnetic resonance cholangiography (MRC) and endoscopic retrograde cholangiography (ERC) in the diagnosis of primary sclerosing cholangitis (PSC).
  
  
  METHODS
  MRC at 1.5 T with thin- and thick-slice breath-hold technique was performed in 66 adult patients (median age, 44 y; 26 women) with an appropriate spectrum of hepatobiliary diseases. Maximum intensity projection images were reconstructed from the thin slices. ERC was performed within 48 hours of the MR examination. The reference standard of PSC diagnosis was based on a combination of clinical features and cholestatic biochemical profile with typical ERC and/or MRC abnormalities and supported by liver histology findings. Two independent reviewers who were unaware of final diagnoses analyzed all images retrospectively.
  
  
  RESULTS
  PSC was diagnosed in 39 (59%) of 66 patients. MRC provided comparable and poorer depiction than ERC of extrahepatic and intrahepatic ducts, respectively. However, the diagnostic accuracy of ERC and MRC were comparable. In the MRC detection of PSC, the average sensitivity of 2 independent readers was 80%, the specificity was 87%, and the accuracy was 83%. The corresponding values for ERC were a sensitivity of 89%, a specificity of 80%, and an accuracy of 85%. Interobserver agreement for the diagnosis of PSC was good (kappa = .61) for MRC and excellent (kappa = .81) for ERC.
  
  
  CONCLUSIONS
  PSC can be diagnosed with high accuracy and good interobserver agreement. MRC and ERC performed equally well in the diagnosis of PSC when used blinded to clinical information.
authors.affiliation: Department of Radiology, Section of Gastroenterology, Rikshospitalet University Hospital, Oslo, Norway. a.e.berstad@medisin.uio.no
authors.forename: Audun Elnaes
authors.initials: AE
authors.lastname: Berstad
authors.forename: Lars
authors.initials: L
authors.lastname: Aabakken
authors.forename: Hans-Jørgen
authors.initials: HJ
authors.lastname: Smith
authors.forename: Steinar
authors.initials: S
authors.lastname: Aasen
authors.forename: Kirsten Muri
authors.initials: KM
authors.lastname: Boberg
authors.forename: Erik
authors.initials: E
authors.lastname: Schrumpf
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002760:Cholangiopancreatography, Endoscopic Retrograde; D049448:Cholangiopancreatography, Magnetic Resonance; D015209:Cholangitis, Sclerosing / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results