title: Utility of pancreatography for diagnosing autoimmune pancreatitis.
abstract: OBJECTIVE
  To identify pancreatographic findings that facilitate differentiating between autoimmune pancreatitis (AIP) and pancreatic cancer (PC) on endoscopic retrograde cholangiopancreatography (ERCP) and magnetic resonance cholangiopancreatography (MRCP).
  
  
  METHODS
  ERCP findings of 48 AIP and 143 PC patients were compared. Diagnostic accuracies for AIP by ERCP and MRCP were compared in 30 AIP patients.
  
  
  RESULTS
  The following ERCP findings suggested a diagnosis of AIP rather than PC. Obstruction of the main pancreatic duct (MPD) was more frequently detected in PC (P < 0.001). Skipped MPD lesions were detected only in AIP (P < 0.001). Side branch derivation from the narrowed MPD was more frequent in AIP (P < 0.001). The narrowed MPD was longer in AIP (P < 0.001), and a narrowed MPD longer than 3 cm was more frequent in AIP (P < 0.001). Maximal diameter of the upstream MPD was smaller in AIP (P < 0.001), and upstream dilatation of the MPD less than 5 mm was more frequent in AIP (P < 0.001). Stenosis of the lower bile duct was smooth in 87% of AIP and irregular in 65% of PC patients (P < 0.001). Stenosis of the intrahepatic or hilar bile duct was detected only in AIP (P = 0.001). On MRCP, diffuse narrowing of the MPD on ERCP was shown as a skipped non-visualized lesion in 50% and faint visualization in 19%, but segmental narrowing of the MPD was visualized faintly in only 14%.
  
  
  CONCLUSIONS
  Several ERCP findings are useful for differentiating AIP from PC. Although MRCP cannot replace ERCP for the diagnostic evaluation of AIP, some MRCP findings support the diagnosis of AIP.
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, Tokyo 113-8677, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Takuma
authors.forename: Terumi
authors.initials: T
authors.lastname: Kamisawa
authors.forename: Taku
authors.initials: T
authors.lastname: Tabata
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Inaba
authors.forename: Naoto
authors.initials: N
authors.lastname: Egawa
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging*; D002760:Cholangiopancreatography, Endoscopic Retrograde; D049448:Cholangiopancreatography, Magnetic Resonance; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D010195:Pancreatitis / Q000000981:diagnostic imaging*