title: Endoscopic retrograde cholangiography does not reliably distinguish IgG4-associated cholangitis from primary sclerosing cholangitis or cholangiocarcinoma.
abstract: OBJECTIVE
  Distinction of immunoglobulin G4-associated cholangitis (IAC) from primary sclerosing cholangitis (PSC) or cholangiocarcinoma is challenging. We aimed to assess the performance characteristics of endoscopic retrograde cholangiography (ERC) for the diagnosis of IAC.
  
  
  METHODS
  Seventeen physicians from centers in the United States, Japan, and the United Kingdom, unaware of clinical data, reviewed 40 preselected ERCs of patients with IAC (n = 20), PSC (n = 10), and cholangiocarcinoma (n = 10). The performance characteristics of ERC for IAC diagnosis as well as the κ statistic for intraobserver and interobserver agreement were calculated.
  
  
  RESULTS
  The overall specificity, sensitivity, and interobserver agreement for the diagnosis of IAC were 88%, 45%, and 0.18, respectively. Reviewer origin, specialty, or years of experience had no statistically significant effect on reporting success. The overall intraobserver agreement was fair (0.74). The operating characteristics of different ERC features for the diagnosis of IAC were poor.
  
  
  CONCLUSIONS
  Despite high specificity of ERC for diagnosing IAC, sensitivity is poor, suggesting that many patients with IAC may be misdiagnosed with PSC or cholangiocarcinoma. Additional diagnostic strategies are likely to be vital in distinguishing these diseases.
authors.affiliation: Department of Gastroenterology, University College Hospital, London, United Kingdom.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kalaitzakis
authors.forename: Michael
authors.initials: M
authors.lastname: Levy
authors.forename: Terumi
authors.initials: T
authors.lastname: Kamisawa
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Johnson
authors.forename: Todd H
authors.initials: TH
authors.lastname: Baron
authors.forename: Mark D
authors.initials: MD
authors.lastname: Topazian
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kanno
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Okazaki
authors.forename: Naoto
authors.initials: N
authors.lastname: Egawa
authors.forename: Kazushige
authors.initials: K
authors.lastname: Uchida
authors.forename: Kashif
authors.initials: K
authors.lastname: Sheikh
authors.forename: Zahir
authors.initials: Z
authors.lastname: Amin
authors.forename: Tooru
authors.initials: T
authors.lastname: Shimosegawa
authors.forename: Neomal S
authors.initials: NS
authors.lastname: Sandanayake
authors.forename: Nicholas I
authors.initials: NI
authors.lastname: Church
authors.forename: Michael H
authors.initials: MH
authors.lastname: Chapman
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Pereira
authors.forename: Suresh
authors.initials: S
authors.lastname: Chari
authors.forename: George J M
authors.initials: GJ
authors.lastname: Webster
mesh_terms: D018281:Cholangiocarcinoma / Q000175:diagnosis*; D002760:Cholangiopancreatography, Endoscopic Retrograde; D002761:Cholangitis / Q000139:chemically induced / Q000175:diagnosis* / Q000209:etiology*; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000706:statistics & numerical data; D006801:Humans; D007074:Immunoglobulin G / Q000008:administration & dosage / Q000009:adverse effects*; D007564:Japan; D012680:Sensitivity and Specificity; D006113:United Kingdom; D014481:United States
chemical_list: D007074:Immunoglobulin G