The typical ultrasound image is characterized by a stone-like strong echogenic mass or high-density image in the liver parenchyma, with irregular shapes such as round or short strips or arcs, usually with no or weak posterior acoustic shadow, and often without the “double line sign” of the bile duct wall; the location of the strong echogenic mass in the liver varies, and there is no obvious dilatation of the hepatobiliary duct proximal to it.