There are three types of cystic dilatation according to the location of the cysts: congenital cystic dilatation of the common bile duct if it occurs in the extrahepatic bile ducts, congenital cystic dilatation of the hepatic bile ducts if it occurs in the intrahepatic bile ducts, also known as calcinosis, and combined cystic dilatation of the intrahepatic and extrahepatic bile ducts at the same time. Sonographic manifestations: 1, cystic dilatation of extrahepatic bile ducts in the area of the common bile duct appeared cysts, mostly spherical, elliptical, can be extended to the liver or the head of the pancreas, the cyst wall is clear, thin, the cystic cavity is liquid echoes, and the posterior echogenicity is enhanced. The size and tension of the cyst are often altered. Careful visualization of the cyst in relation to the proximal hepatic ducts is important. The intrahepatic bile ducts are often mildly dilated. The gallbladder is often displaced. 2, cystic dilatation of intrahepatic bile ducts ultrasound shows that the cysts extend the distribution of the right and left hepatic ducts and connect with the hepatic ducts, the strong echogenicity of the cyst wall is clear, the cystic lumen is round or pike-type translucent dark areas. The cystic lumen is rounded or spindle-shaped with dark areas of translucency. It may also appear as a segmental or relatively homogeneous dilatation. Sometimes it can be combined with cystic dilatation of extrahepatic bile ducts.