title: Autoimmune pancreatitis: assessment of the enhanced duct sign on multiphase contrast-enhanced computed tomography.
abstract: OBJECTIVE
  To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the "enhanced duct sign", for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis.
  
  
  METHODS
  Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n=55), pancreatic carcinoma (n=50), and chronic pancreatitis (n=50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus.
  
  
  RESULTS
  The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P<0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%).
  
  
  CONCLUSIONS
  The enhanced duct sign is highly specific of AIP.
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine, and Department of Diagnostic Radiology, Japan Red Cross Nagoya Daiichi Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan. kawai.yuichi@a.mbox.nagoya-u.ac.jp
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kawai
authors.forename: Kojiro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Shigeki
authors.initials: S
authors.lastname: Itoh
authors.forename: Akira
authors.initials: A
authors.lastname: Takada
authors.forename: Yoshine
authors.initials: Y
authors.lastname: Mori
authors.forename: Shinji
authors.initials: S
authors.lastname: Naganawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007455:Iodine / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010183:Pancreatic Ducts / Q000000981:diagnostic imaging*; D010195:Pancreatitis / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine