Causes of intrahepatic shadowing on ultrasound examination

Acoustic shadowing on ultrasound examination of the liver can be caused by both normal anatomical structures (ligamentum teres, walls of bile ducts and portal veins, interpositioned colon) as well as by abnormalities which may or may not be clinically important (air in the bile ducts, biliary calculi, calcified granulomas, foreign bodies). Acoustic shadowing is more frequently seen when high frequency transducers or lower gain at scanning are used.