[Difficulties in the differential x-ray diagnosis of choledocholithiasis]

The authors consider some difficulties in the roentgenological interpretation of the filling defect in the biliary tracts revealed by a direct contrast study using the TTC or ERCG methods. The greatest difficulties are observed in the presence of the parietal defect that can be determined by an undisplaceable concrement, a small polypoid cancer of the duct and metastases to the lymph nodes, the lesser omentum along the common bile and hepatic ducts. To differentiate between these diseases one should bear in mind a degree of outlining the filling defect with a contrast medium, the presence of a constricted area below the defect, local tenderness, and bile infectiousness. The authors also consider a problem of how to interpret the symptom of a "snake mouth" or a "concave lens" which (depending on its cause) can be either transient (in a large concrement) or stable (in an exophytic tumor, completely occluding the duct).