title: Comparative MRI analysis of morphologic patterns of bile duct disease in IgG4-related systemic disease versus primary sclerosing cholangitis.
abstract: OBJECTIVE
  The purpose of this study was to perform a retrospective MRI-based comparative analysis of the morphologic patterns of bile duct disease in IgG4-related systemic disease (ISD, also called autoimmune pancreatitis) compared with primary sclerosing cholangitis (PSC) and the autoimmune liver diseases autoimmune hepatitis and primary biliary cirrhosis.
  
  
  METHODS
  This study included 162 consecutively registered patients (47 with ISD, 73 with PSC, and 42 with autoimmune liver diseases). Two abdominal radiologists retrospectively reviewed MR images in consensus. Imaging findings on the bile ducts, liver, pancreas, and other organs were analyzed to establish disease patterns.
  
  
  RESULTS
  ISD was associated with contiguous thickening of intrahepatic and extrahepatic bile ducts (p<0.001), pancreatic parenchymal abnormalities (p<0.001), renal abnormalities (p<0.001), and gallbladder wall thickening (p<0.03). The severity of common bile duct wall thickness was significantly different in ISD (p<0.001). The mean single wall thickness in the ISD group was 3.00 (SD, 1.47) mm, in the PSC group was 1.89 (SD, 0.73) mm, and in the autoimmune liver disease group was 1.80 (SD, 0.67) mm. PSC was associated with liver parenchymal abnormalities (p<0.001). We did not find statistical significance between the three groups in location (p=0.220) or length (p=0.703) of extrahepatic bile duct strictures, enhancement of bile duct stricture (p=0.033), upper abdominal lymphadenopathy, or retroperitoneal fibrosis. Although presence of intrahepatic bile duct stricture was statistically significant when all three groups were compared, it was not useful for differentiating ISD from PSC.
  
  
  CONCLUSIONS
  The presence of continuous as opposed to skip disease in the bile ducts, gallbladder involvement, and single-wall common bile duct thickness greater than 2.5 mm supports a diagnosis of ISD over PSC. ISD and PSC could not be differentiated on the basis of location and length of common bile duct stricture.
authors.affiliation: 1 Department of Medical Imaging, Abdominal Imaging, University Health Network, Mount Sinai Hospital and Women's College Hospital, University of Toronto, 610 University Ave, Toronto, ON M5G 2M9, Canada.
authors.forename: Ajay
authors.initials: A
authors.lastname: Tokala
authors.forename: Korosh
authors.initials: K
authors.lastname: Khalili
authors.forename: Ravi
authors.initials: R
authors.lastname: Menezes
authors.forename: Gideon
authors.initials: G
authors.lastname: Hirschfield
authors.forename: Kartik S
authors.initials: KS
authors.lastname: Jhaveri
mesh_terms: D000328:Adult; D001327:Autoimmune Diseases / Q000150:complications* / Q000276:immunology / Q000473:pathology*; D001649:Bile Duct Diseases / Q000150:complications* / Q000473:pathology*; D015209:Cholangitis, Sclerosing / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D007074:Immunoglobulin G