Low conjunction of the cystic duct with the common bile duct: does it correlate with the formation of common bile duct stones?

Abstract

Background: This study aimed to evaluate the accuracy of magnetic resonance cholangiography (MRC) in detecting variants of low cystic duct conjunction, which can be a source of confusion during surgery when unrecognized.

Methods: All cases with both MRC and endoscopic retrograde cholangiography (ERC) indicating suspected common bile duct stones between January 1999 and January 2004 were retrospectively reviewed by investigators blinded to the final diagnosis. Assessment with ERC was regarded as the gold standard. The aim was to find a low conjunction of the cystic duct with the bile duct. The sensitivity and specificity of MRC were calculated in comparison with those for ERC. The cystic junction radial orientation was defined as lateral (insertion diagonally from the right), medial (insertion into the left side of the common hepatic duct), or posteroanterior (overlap of the junction with the bile duct in the posteroanterior view). A spiral cystic duct and a long parallel course were evaluated separately.

Results: Low insertion of the cystic duct was found on ERC in 66 of 622 patients (11%; 28 men and 38 women; mean age, 64.5 years). The sensitivity and specificity of MRC for detecting low cystic entrance were 100% (90.4% on an intention-to-diagnose basis and 100%, respectively). In 11 patients (16.6%), the radial orientation of the cysticohepatic junction could not be defined with MRC. The rate of correct MRC delineation was 95% for lateral (n = 21), 77% for medial (n = 26), and 74% for posteroanterior (n = 19) insertion of the cystic duct.

Conclusion: The findings showed that MRC has good correlation with ERC with regard to the location and anatomic details of cystic duct insertion. Although this does not generate a separate indication for MRC before laparoscopic cholecystectomy, the anatomic information can be of additional use when MRC is clinically indicated in this setting.