What is the appearance of gallstones on Ultrasound?
US is the modality of choice for detecting gallstones. Gallstones appear as rounded echogenic structures in the gallbladder lumen with posterior acoustic shadowing. Stones smaller than 5 mm may not shadow but will still appear echogenic. Gallstones are also typically mobile. Gallstones may also be seen in association with biliary sludge, which appears as dependent, low-level layering echogenic material in the gallbladder