Diagnostic Ultrasound - Abdomen and Pelvis

Intrahepatic and Extrahepatic Duct Dilatation
Differential Diagnoses: Biliary System
DIFFERENTIAL DIAGNOSIS
Common
• Choledocholithiasis
• Ascending Cholangitis
• Recurrent Pyogenic Cholangitis
• Pancreatic Ductal Carcinoma
• Cholangiocarcinoma
• Choledochal Cyst
Less Common
• Sludge
• Periampullary Tumor
• Sclerosing Cholangitis
• Parasitic Infestation
• AIDS-Related Cholangiopathy
• Biliary Intraductal Papillary Mucinous Neoplasm
ESSENTIAL INFORMATION
Helpful Clues for Common Diagnoses
• Choledocholithiasis
○ Most common location is in common bile duct (CBD)
○ Round echogenic focus with marked posterior acoustic
shadowing
• Ascending Cholangitis
○ Imaging may reveal biliary duct wall thickening,
intraluminal debris, or obstructing biliary stone
○ Periportal inflammatory hypo-/hyperechogenicity may
be seen
• Recurrent Pyogenic Cholangitis
○ Bacterial colonization of brown pigment stones in both
intrahepatic and extrahepatic bile ducts
○ Densely packed intrahepatic stones
○ Atrophy of involved lobe/segment of liver in later stages
• Pancreatic Ductal Carcinoma
○ Ill-defined, solid mass in pancreatic head
○ Pancreatic duct dilatation that abruptly tapers at point of
pancreatic carcinoma
○ Vascular encasement ± regional nodal/liver metastases
• Cholangiocarcinoma
○ Extrahepatic cholangiocarcinoma involves biliary ducts in
hepatoduodenal ligament
– Intra- and extrahepatic biliary dilatation
– May see: Irregular soft tissue thickening of
extrahepatic bile duct or polypoidal mass within CBD
○ Intrahepatic cholangiocarcinoma: Ill-defined, infiltrative,
iso-/hyperechoic mass often with capsular retraction
• Choledochal Cyst
○ Congenital biliary malformation characterized by
fusiform duct dilatation
○ Most commonly involves CBD
○ Cystic extrahepatic mass separated from gallbladder and
communicating with CHD or intrahepatic ducts
○ Fusiform dilatation of extra- ± intrahepatic bile ducts
○ Abrupt change in caliber at junction of dilated segment
to normal ducts
Helpful Clues for Less Common Diagnoses
• Sclerosing Cholangitis
○ Autoimmune disease that causes multiple intra- and
extrahepatic biliary strictures with dilatation
• Biliary Intraductal Papillary Mucinous Neoplasm
○ Ductal intraluminal mass with frond-like papillary
projections
○ Hypersecretion of mucin as well as anatomic obstruction
leads to markedly dilated intra- and extrahepatic biliary
ducts
SELECTED REFERENCES
1. Plentz RR et al: Clinical presentation, risk factors and staging systems of
cholangiocarcinoma. Best Pract Res Clin Gastroenterol. 29(2):245-252, 2015
2. Raman SP et al: Abnormalities of the Distal Common Bile Duct and Ampulla:
Diagnostic Approach and Differential Diagnosis Using Multiplanar
Reformations and 3D Imaging. AJR Am J Roentgenol. 203(1):17-28, 2014
3. Attasaranya S et al: Choledocholithiasis, ascending cholangitis, and gallstone
pancreatitis. Med Clin North Am. 92(4):925-60, x, 2008
4. Lim JH et al: Biliary intraductal papillary-mucinous neoplasm manifesting
only as dilatation of the hepatic lobar or segmental bile ducts: imaging
features in six patients. AJR Am J Roentgenol. 191(3):778-82, 2008
(Left) Grayscale ultrasound of
the liver shows mild biliary
ductal dilatation of the
common bile duct as well
as mildly prominent
intrahepatic biliary ducts
creating subtle double ducts
. The cause of mild biliary
ductal dilatation was due to
an obstructing stone in the
common bile duct (not shown).
(Right) Longitudinal oblique
grayscale US of the liver shows
a markedly dilated common
duct with layering debris
st in a patient with ascending
cholangitis.
Choledocholithiasis
Ascending Cholangitis
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