Exploring the length of the common channel of pancreaticobiliary maljunction on magnetic resonance cholangiopancreatography.

BackgroundIn the revised diagnostic criteria for pancreaticobiliary maljunction (PBM), PBM can be diagnosed from a long common channel by magnetic resonance cholangiopancreatography (MRCP). However, it is necessary to differentiate from high confluence of pancreaticobiliary ducts (HCPBD) with a relatively long common channel (6mm) and effect of the sphincter in the pancreaticobiliary junction. This multicenter study aimed to explore definite value of the length of an abnormally long common channel, which enables to distinguish PBM from HCPBD on MRCP. MethodsIn 184 PBM patients and 22 HCPBD patients who were diagnosed by direct cholangiography and underwent MRCP, the length of the common channel was measured. ResultsThe length of the common channel was 16.2 6.9mm on direct cholangiography and 13.9 +/- 6.2mm on MRCP in PBM patients, and 7.7 +/- 1.5mm and 6.6 +/- 1.4mm in HCPBD patients. The optimal cut off value of the length of the common channel to distinguish PBM from HCPBD was identified to be 9mm. ConclusionsPancreaticobiliary maljunction can be diagnosed from an abnormally long common channel on MRCP, but in cases of the common channel 9mm on MRCP, direct cholangiography is needed to confirm PBM.