In patients with a common bile duct stone, what ultrasound finding is commonly observed?

In patients with a common bile duct stone, the ultrasound finding of intrahepatic biliary dilation is commonly observed due to the obstruction of bile flow. When a stone becomes lodged in the common bile duct, it prevents bile from flowing from the liver to the intestine. This backing up of bile causes the intrahepatic biliary tree—the bile ducts located within the liver—to dilate as the pressure builds up from the accumulation of bile.

On an ultrasound examination, this dilation can be visualized as enlarged bile ducts within the liver, often demonstrating a central echogenicity with surrounding hypoechoic ductal walls. The presence of intrahepatic biliary dilation is a key indicator of biliary obstruction and suggests the need for further evaluation or intervention to address the obstructive cause, such as the common bile duct stone.