Differentiation of Intraductal Growing-type Cholangiocarcinomas from Nodular-type Cholangiocarcinomas at Biliary MR Imaging with MR Cholangiography

Purpose: To describe the magnetic resonance (MR) findings of intraductal growing (IDG)-type cholangiocarcinoma (CC) and to identify the features that differentiate it from nodular-type CC. Materials and Methods: The institutional review board approved this retrospective study and waived the informed consent requirement. Thirty-nine patients with pathologically proved IDG-type (n = 19) or nodular-type (n = 20) CCs who had undergone preoperative gadolinium-enhanced MR imaging with MR cholangiography were included in this study. Analysis of MR findings included determination of the (a) shape, enhancement degree, and pattern of the tumor; (b) outer caliber of the tumor-bearing segment; and (c) presence of tumor multiplicity, upstream and downstream bile duct dilatation, bile duct wall thickening adjacent to the tumor, and adjacent organ invasion. The significance of these findings was determined with the x(2) test. Results: Significant features in the differentiation of IDG-type CCs from nodular-type CCs included papillary or irregular polypoid shape, lack of constriction of the tumor-bearing segment, hypoenhancement of the tumor to the liver during the equilibrium phase, tumor multiplicity, upstream and downstream bile duct dilatation, and no bile duct wall thickening adjacent to the tumor (P < .05). When at least two of these six imaging features were used in combination, sensitivity and specificity in the diagnosis of IDG-type CCs were 95% and 70%, respectively. C Conclusion: By using characteristic MR features, one can differentiate IDG-type CC from nodular-type CC with a high degree of accuracy at biliary MR imaging with MR cholangiography. (C) RSNA, 2010