title: Differentiation of extrahepatic bile duct cholangiocarcinoma from benign stricture: findings at MRCP versus ERCP.
abstract: OBJECTIVE
  To retrospectively evaluate criteria for differentiating extrahepatic bile duct cholangiocarcinoma from benign cause of stricture at magnetic resonance cholangiopancreatography (MRCP) and to compare diagnostic accuracy with this modality versus endoscopic retrograde cholangiopancreatography (ERCP).
  
  
  METHODS
  MRCP and ERCP images in 50 patients (27 with cholangiocarcinoma [18 men, nine women; mean age, 58 years] and 23 with benign cause of stricture [13 men, 10 women; mean age, 60 years]) were retrospectively reviewed to assess the appearance of bile duct strictures. Final diagnosis was based on surgical or biopsy findings. Strictures were described according to their imaging appearance (irregular or smooth margins, asymmetric or symmetric narrowing, abrupt narrowing or gradual tapering, and presence or absence of double-duct sign). Sensitivity, specificity, and accuracy of MRCP and ERCP were calculated by using ratings of confidence in image-based diagnosis. Lengths of stricture were electronically measured and compared by using the Student t test.
  
  
  RESULTS
  Among cholangiographic criteria for malignant biliary stricture, irregular margins and asymmetric narrowing were more common in cholangiocarcinomas (24 [89%] of 27 patients) than in benign strictures (six [26%] and eight [35%] of 23 patients, respectively). Sensitivity, specificity, and accuracy of the two methods for differentiation of malignant from benign causes of biliary stricture were 81% (22 of 27), 70% (16 of 23), and 76% (38 of 50), respectively, for MRCP and 74% (20 of 27), 70% (16 of 23), and 72% (36 of 50), respectively, for ERCP. Mean length (+/- standard deviation) of cholangiocarcinomas was 30.0 mm +/- 8.5, and that of benign strictures was 13.6 mm +/- 9.1 (P <.001).
  
  
  CONCLUSIONS
  Accuracy of MRCP is comparable with that of ERCP. Regardless of modality, a lengthy segment of extrahepatic bile duct stricture with irregular margin and asymmetric narrowing suggests cholangiocarcinoma, and a short segment with regular margin and symmetric narrowing suggests benign cause.
authors.affiliation: Depts of Diagnostic Radiology and Pathology, Asan Medical Ctr, Univ of Ulsan College of Medicine, 388-1 Poongnap Dong Songpa-Ku, Seoul 138-040, South Korea.
authors.forename: Mi-Suk
authors.initials: MS
authors.lastname: Park
authors.forename: Tae Kyoung
authors.initials: TK
authors.lastname: Kim
authors.forename: Kyoung Won
authors.initials: KW
authors.lastname: Kim
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Park
authors.forename: Jeong Kyung
authors.initials: JK
authors.lastname: Lee
authors.forename: Jung-Sun
authors.initials: JS
authors.lastname: Kim
authors.forename: Jean Hwa
authors.initials: JH
authors.lastname: Lee
authors.forename: Kyoung Ah
authors.initials: KA
authors.lastname: Kim
authors.forename: Ah Young
authors.initials: AY
authors.lastname: Kim
authors.forename: Pyo Nyun
authors.initials: PN
authors.lastname: Kim
authors.forename: Moon-Gyu
authors.initials: MG
authors.lastname: Lee
authors.forename: Hyun Kwon
authors.initials: HK
authors.lastname: Ha
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000097:blood; D001649:Bile Duct Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D001650:Bile Duct Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D017734:Bile Ducts, Extrahepatic / Q000000981:diagnostic imaging / Q000473:pathology*; D001663:Bilirubin / Q000097:blood; D018395:CA-19-9 Antigen / Q000097:blood; D018281:Cholangiocarcinoma / Q000175:diagnosis* / Q000000981:diagnostic imaging; D002760:Cholangiopancreatography, Endoscopic Retrograde; D003251:Constriction, Pathologic / Q000175:diagnosis / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D018395:CA-19-9 Antigen; D000469:Alkaline Phosphatase; D001663:Bilirubin