The whole extrahepatic bile duct seen under transabdominal ultrasound after normal saline retention enema. The whole compensatory dilated extrahepatic bile duct (indicated by BD and the arrows) is visible behind the transverse colon (indicated by C). Indicated by A and the arrows is the upper bound of the overlapping between the extrahepatic bile duct and transverse colon, and indicated by B and the arrows is the lower bound of the overlapping. This patient was checked after cholecystectomy, and no calculus or cancer was found, which is not included in the cases studied in this article. It is just taken as an example to describe the effect of visualizing the extrahepatic bile duct after the enema.