title: Can MRCP replace ERCP for the diagnosis of autoimmune pancreatitis?
abstract: BACKGROUND
  It is of utmost importance that autoimmune pancreatitis (AIP) be differentiated from pancreatic cancer. Irregular narrowing of the main pancreatic duct is a characteristic finding in AIP; it is useful for differentiating AIP from pancreatic cancer stenosis. This study evaluated the usefulness of magnetic resonance cholangiopancreatography (MRCP) for the diagnosis of AIP and assessed whether MRCP could replace endoscopic retrograde cholangiopancreatography (ERCP) for diagnosing AIP.
  
  
  METHODS
  The MRCP and ERCP findings of 20 AIP patients were compared.
  
  
  RESULTS
  On MRCP, the narrowed portion of the main pancreatic duct was not visualized, while the noninvolved segments of the pancreatic duct were visualized. The degree of upstream dilatation of the proximal main pancreatic duct was milder in AIP than in pancreatic cancer patients. In the skipped type, only skipped narrowed lesions were not visualized. After steroid therapy for AIP, the nonvisualized main pancreatic duct became visualized.
  
  
  CONCLUSIONS
  MRCP cannot replace ERCP for the diagnosis of AIP, since narrowing of the main pancreatic duct in AIP was not visualized on MRCP. MRCP findings of segmental or skipped nonvisualized main pancreatic duct accompanied by a less dilated upstream main pancreatic duct may suggest the presence of AIP. MRCP is useful for following AIP patients.
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, Tokyo, Japan. kamisawa@cick.jp
authors.forename: T
authors.initials: T
authors.lastname: Kamisawa
authors.forename: Y
authors.initials: Y
authors.lastname: Tu
authors.forename: N
authors.initials: N
authors.lastname: Egawa
authors.forename: K
authors.initials: K
authors.lastname: Tsuruta
authors.forename: A
authors.initials: A
authors.lastname: Okamoto
authors.forename: M
authors.initials: M
authors.lastname: Kodama
authors.forename: N
authors.initials: N
authors.lastname: Kamata
mesh_terms: D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000473:pathology; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000379:methods*; D049448:Cholangiopancreatography, Magnetic Resonance / Q000379:methods*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010183:Pancreatic Ducts / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D010195:Pancreatitis / Q000175:diagnosis* / Q000473:pathology