Differentiation of extrahepatic bile duct cholangiocarcinoma from benign stricture: findings at MRCP versus ERCP.
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.
Park
Mi-Suk
MS
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.
Kim
Tae Kyoung
TK
Kim
Kyoung Won
KW
Park
Sung Won
SW
Lee
Jeong Kyung
JK
Kim
Jung-Sun
JS
Lee
Jean Hwa
JH
Kim
Kyoung Ah
KA
Kim
Ah Young
AY
Kim
Pyo Nyun
PN
Lee
Moon-Gyu
MG
Ha
Hyun Kwon
HK
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
D018395:CA-19-9 Antigen; D000469:Alkaline Phosphatase; D001663:Bilirubin