title: Differentiation of benign and malignant ampullary obstructions on MR imaging.
abstract: OBJECTIVE
  To define diagnostic criteria for differentiating malignant ampullary carcinoma from benign ampullary obstruction on MR imaging.
  
  
  METHODS
  Nineteen patients with ampullary carcinoma and 22 patients with benign ampullary obstruction were enrolled. At the first session, two radiologists independently evaluated specific imaging findings, and then reached consensus decisions. At the second session, another two radiologists, who were informed about useful differentiation criteria based on the results from the first session, reviewed images and determined the causes of ampullary obstruction. Sensitivity and specificity were calculated for each interpretation session, and the Cohen κ statistic was used to evaluate interobserver agreement.
  
  
  RESULTS
  Findings of the presence of an ampullary mass (P<0.001), papillary bulging (P<0.001), irregular (P=0.021) and asymmetric (P<0.001) common bile duct (CBD) narrowing, and proportional biliary dilatation (P<0.001) were more commonly seen in patients with an ampullary carcinoma. The sensitivity and specificity of the first session were 84.2% and 86.4% after consensus. The sensitivity increased to 100% for both the readers at the second session, while the specificity decreased to 63.6% and 59.1%, respectively.
  
  
  CONCLUSIONS
  Identification of an ampullary mass, papillary bulging, irregular and asymmetric narrowing of the CBD, or proportional biliary dilatation may improve the diagnosis of ampullary carcinoma in patients with ampullary obstruction.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Chung
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Hye Mi
authors.initials: HM
authors.lastname: Kim
authors.forename: Mi-Suk
authors.initials: MS
authors.lastname: Park
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Hye-Suk
authors.initials: HS
authors.lastname: Hong
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014670:Ampulla of Vater / Q000473:pathology*; D003138:Common Bile Duct Neoplasms / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity