Figure 2  .

A single 10 mm bile duct stone shown by endosonography (A) and helical computed tomographic (HCT)-cholangiography (B, C). (A) A hyperechoic structure (white arrow) is seen associated with acoustic shadowing (black arrowheads), which is a typical appearance of a stone at endosonography; CBD indicates the common bile duct. (B) HCT-cholangiography; an axial image at the level of the distal common bile duct shows a filling defect (black arrow) which corresponds to the stone seen at endosonography. White arrowheads delineate the cross section of the common bile duct containing contrast enhanced bile. (C) HCT-cholangiography; multiplanar reconstruction image in the same patient. The stone (white arrow) is seen as a polygonal filling defect.