On abdominal ultrasound, cholangiocarcinoma is characterized by obstruction and dilation of bile ducts. Mass-forming intrahepatic cholangiocarcinoma is characterized by homogenous mass of intermediate echogenicity with a peripheral hypoechoic halo of compressed liver. Periductal infiltrating intrahepatic cholangiocarcinoma is characterized by capsular retraction. Intraductal cholangiocarcinoma is characterized by alterations in duct caliber, usually duct ectasia with or without a visible mass.

• Contrast-enhanced ultrasound may be helpful in the diagnosis of cholangiocarcinoma. Findings on an ultrasound diagnostic of cholangiocarcinoma include:
• Arterial phase:

• Peripheral irregular rim-like enhancement
• Heterogeneous central hypoenhancement

• Portal venous phase/delayed phase:

• Decreased echogenicity relative to background liver (“wash out”)

• Findings on an ultrasound diagnostic of mass-forming intrahepatic cholangiocarcinoma include:
  • Capsular retraction
  • Homogeneous mass of intermediate echogenicity with a peripheral hypoechoic halo of compressed liver

• Findings on an ultrasound diagnostic of periductal infiltrating cholangiocarcinoma include:
  • Altered caliber bile duct (narrowed or dilated) without a well-defined mass

• Findings on an ultrasound diagnostic of intraductal cholangiocarcinoma include:
  • Alterations in duct caliber, usually duct ectasia with or without a visible mass