Diagnostic Ultrasound - Abdomen and Pelvis

Biliary Ductal Dilatation
Diagnoses: Biliary System
TERMINOLOGY
• Biliary ductal dilatation, dilated ducts
IMAGING
• Tubular anechoic fluid-filled structures accompanying
portal veins in extrahepatic and intrahepatic segments
• Intrahepatic ductal dilatation
○ Dilatation of ductal diameter > 2 mm
• Extrahepatic ductal dilatation
○ Dilatation of common hepatic/bile duct > 6-7 mm or
more than 40% of diameter of adjacent portal vein
TOP DIFFERENTIAL DIAGNOSES
• Portal vein cavernoma
• Thrombosed portal vein branch
• Venovenous collaterals
• Peribiliary cysts
• Choledochal cyst
KEY FACTS
PATHOLOGY
• Obstructive causes
○ Intrahepatic: Calculus, recurrent pyogenic cholangitis,
sclerosing/AIDS cholangitis, cholangiocarcinoma, etc.
○ Extrahepatic: Calculus, stricture, pancreatic head
adenocarcinoma, cholangiocarcinoma, lymph node
compression, etc.
• Nonobstructive causes
○ Advanced age
○ Previous cholecystectomy
○ Congenital disease (e.g., choledochal cyst)
○ Hepatic artery stenosis in liver transplant recipients
CLINICAL ISSUES
• Presentation
○ Often presents with obstructive jaundice: Painless or
right upper quadrant pain
(Left) Oblique transabdominal
US through the liver shows
moderate dilatation of the
common bile duct ſt and
branching intrahepatic ducts
caused by an obstructing
pancreatic head tumor (not
shown). (Right) Lack of flow in
the dilated tubular structures
on this color Doppler
ultrasound in the same patient
confirms that these are indeed
dilated biliary ducts. Color
Doppler should be used
routinely to confirm biliary
ductal dilatation.
(Left) Transverse color
Doppler ultrasound of the liver
shows mild biliary ductal
dilatation in the intrahepatic
ducts st, which measured just
over 2 mm in diameter. The
cause of mild biliary ductal
dilatation was due to
obstructing stone (not shown).
(Right) Transverse color
Doppler image of the liver
shows mild biliary ductal
dilatation in the intrahepatic
ducts st, as well as
extrahepatic ducts . Patient
was found to have both
ampullary stenosis, as well as
cholangitis as cause of biliary
ductal dilatation.
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