[Anatomic variations of the bile ducts: MRCP findings]

Anatomic variations of intra or extrahepatic bile ducts may be problematic during surgical procedures. Besides iatrogenic trauma of the bile ducts during cholecystectomy, formation of bile duct stones, recurrent pancreatitis, cholangitis and biliary malignancies can be seen. The aim of this study was to evaluate the frequency of anatomic variations of the biliary tree and to present the magnetic resonance cholangiopancreatography (MRCP) findings.

Between July 2000 and April 2004, 581 patients suspected to have pancreatobiliary disease, were referred to our MR unit. Four hundred and seventy-five patients with ages ranging from 22 to 88 (median: 56) were included in the study retrospectively. MRCP was performed on a 1 Tesla MR unit, using phased-array coil for signal detection. Heavily T2 weighted images were obtained with SSFSE technique. Axial and coronal source images and reformatted images were all evaluated together for the possibility of any anatomic variation.

Anatomic variations at different levels of biliary tree were found in 115 patients (24.2%). MRCP showed an aberrant right hepatic duct in 23 patients (4.8%), a right posterior hepatic duct in 27 patients (5.7%), trifurcation in 4 patients (0.8%), a long cystic duct in 8 patients (1.7%), a medial cystic duct insertion in 3 patients (0.63%), a low medial cystic duct insertion in 18 patients (3.8%), a short cystic duct in 1 patient (0.2%), a high localized gallbladder in 5 patients (1%), a vascular compression of common hepatic duct in 12 patients (2.5%), a pancreatobiliary junction anomaly in 3 patients (0.63%). Eleven patients had more than one anatomic variation (2.3%).

MRCP is a useful, rapid, and non-invasive method for demonstrating the anatomy and the variations of the biliary tree. Diagnosis of these anatomic variations prior to surgical procedures may prevent iatrogenic injury to bile ducts.