What finding in a sonogram suggests biliary obstruction rather than cirrhosis?

Biliary dilation is a key finding in a sonogram that suggests biliary obstruction. When there is an obstruction in the bile ducts, the bile cannot flow normally into the intestines, leading to a back-up of bile within the biliary tree. This back-up causes the bile ducts to become enlarged or dilated, which is a clear indication of an obstruction in the biliary system.

In contrast, conditions like cirrhosis do not typically lead to dilation of the biliary tree. Instead, cirrhosis presents with different sonographic features, such as changes in liver architecture and potentially hepatomegaly, but not exclusively dilation of the bile ducts. Understanding these distinctions is crucial for accurate diagnosis and management in patients with liver and biliary conditions. Moreover, a hepatic mass or portal vein thrombosis might also be visible on a sonogram; however, they do not specifically indicate a biliary obstruction.