RESUMEN
The congenital anomalies of the common bile duct (CBD) represent a real challenge for the surgeon, and not recognizing them may have two consequences: either generate incomplete or incorrect surgical solutions, or, even worse, lead to iatrogenic pathology. The association between the anomalies of the CBD and biliary lithiasis, biliary cancer or other hepatobiliopancreatic pathology may lead to a pre/perioperative diagnosis; frequently, the incertitude persists. We present 2 cases: one with an incomplete duplication of the CBD and the other with a false duplication. We wish to underline the sovereign value of cholangio-MRI with 3 D reconstructions in the diagnosis and description of the anatomy of the biliary ducts, superior, in some cases, to the intraoperative cholangiography or ERCP.