USG OF BILIARY SYSTEM

• US is the most accurate modality for the diagnosis of gallbladder stones, which appear as echogenic foci producing acoustic shadows

•  ‘double-arc shadow’ sign in the gallbladder fossa is seen in gall bladder filled with stones.

• ‘Comet-tail’ ring-down artefacts is noted in adenomatous hyperplasia.

• A diameter of >7 mm of CBD is commonly used as a predictor of bile duct obstruction in the jaundiced patient 

• Mirizzi syndrome is characterized by narrowing of the common duct caused by inflammation and fibrosis related to chronic gallstone disease. Typically a stone is impacted in the neck of the gallbladder, the cystic duct, or cystic duct remnant

• CT is less accurate than US for acute cholecystitis