KEY FACTS
Terminology
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Biliary ductal dilatation, dilated ducts
Imaging
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Tubular anechoic fluid-filled structures accompanying portal veins in extrahepatic and intrahepatic segments
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Intrahepatic ductal dilatation
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Dilatation of ductal diameter > 2 mm
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Extrahepatic ductal dilatation
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Dilatation of common hepatic/bile duct > 6-7 mm or > 40% of diameter of adjacent portal vein
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Top Differential Diagnoses
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Portal vein cavernoma
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Thrombosed portal vein branch
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Venovenous collaterals
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Peribiliary cysts
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Choledochal cyst
Pathology
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Obstructive causes
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Intrahepatic: Calculus, recurrent pyogenic cholangitis, sclerosing/AIDS cholangitis, cholangiocarcinoma, etc.
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Extrahepatic: Calculus, stricture, pancreatic head adenocarcinoma, cholangiocarcinoma, lymph node compression, etc.
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Nonobstructive causes
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Advanced age
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Previous cholecystectomy
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Congenital disease (e.g., choledochal cyst)
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Hepatic artery stenosis in liver transplant recipients
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Clinical Issues
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Presentation
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Often presents with obstructive jaundice: Painless or right upper quadrant pain
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Scanning Tips
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Confirm with color or power Doppler that tubular structure is nonvascular, and follow tubular structure to porta hepatis to confirm communication with common bile duct
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Dilated bile ducts are often tortuous and may demonstrate posterior acoustic enhancement
