To explore the occurrence of pancreaticobiliary maljunction (PBM) in the Chinese population, the characteristics of various subtypes, and the relationship between PBM and malignant tumors of the biliary system. To explore the general clinical characteristics of patients with mild bile duct dilation but who have not been clinically diagnosed with choledochal cysts, as well as the relationship between these characteristics and malignant tumors of the biliary system. To develop and evaluate a deep learning method for machine learning of Magnetic resonance cholangiopancreatography (MRCP) images, enabling fully automated detection of pancreaticobiliary maljunction.

Inclusion Criteria:

Cases that were hospitalized and underwent Magnetic resonance cholangiopancreatography (MRCP) examination at the First Medical Center of Chinese People's Liberation Army General Hospital.

Exclusion Criteria:

1. Patients aged less than 18 years old;
2. Those with unclear diagnosis;
3. Cases with missing or poor-quality imaging data.

patients with pancreaticobiliary maljunction