What does the "double-duct sign" indicate on an ultrasound?

The "double-duct sign" on ultrasound refers to the simultaneous dilation of both the common bile duct and the pancreatic duct. This finding is most frequently associated with distal common bile duct obstruction, which is often caused by a mass, such as a pancreatic tumor. The obstruction leads to the backup of bile and pancreatic juices, causing both ducts to become enlarged.

In the context of ultrasound imaging, the presence of the double-duct sign can provide crucial diagnostic information indicating that there is an obstruction requiring further investigation and potential treatment. The pathology is significant, particularly in cases of pancreatic head tumors, where the growth may compress or obstruct these ducts, leading to the characteristic dilations observable on imaging studies.

Other choices, while they may present distinctive sonographic findings, do not relate to the double-duct sign. For instance, gallstones in the bladder would not show this characteristic dilation of the two ducts. Similarly, dilated ureters and hydronephrosis pertain to urinary tract issues, while pancreatic enlargement generally indicates inflammation or other conditions affecting the pancreas but does not specifically link to the double-duct sign.