The extrahepatic biliary system consists of the structures outside the liver that are responsible for collecting and delivering bile to the duodenum. These include the right and left hepatic ducts, the common hepatic duct, the cystic duct, the gallbladder, and the common bile duct. On ultrasound, these structures are routinely evaluated during right upper quadrant examinations, with particular attention to the common bile duct diameter, the presence of stones, and any signs of obstruction. The gallbladder is the most readily visible component, while the distal common bile duct can be challenging to image due to overlying bowel gas. A thorough evaluation of the extrahepatic biliary system is fundamental to abdominal ultrasound and is essential for diagnosing conditions ranging from gallstones to pancreatic cancer.
Sonography Term