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19 Cards in this Set
- Front
- Back
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Normal cystic duct average diameter
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2mm
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Size of the CBD
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1mm/decade starting at 4mm
-60 yrs old: 6mm |
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Post Op extrahepatic bile ducts can dilate up to:
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Can dilate up to 10cm
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Pitfalls in imaging intrahepatic bile ducts:
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Large hepatic arteries, pneumobilia, parenchymas calcifications, peribiliary cysts pneumobilia, parenchymal calcifications, peribiliary cysts
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Primary reason for US in the bile ducts
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Determine whether an obstruction is present, and if so, at what level
Extrahepatic obstruction occurs before intrahepatic obstruction |
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Intrapancreatic Obstruction
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90% of biliary obstruction occur in the head of the pancreas
Pancreatic carcinoma, choledochochalithiasis, chronic pancreatitis w/ stricture formation |
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Suprapancreatic Obstruction
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Obstructions occuring between the pancreas and porta hepatis
Caused by bile duct malignancies |
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Suprapancreatic Obstruction sonographically:
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Mimics a dilated duct filled w/ echogenic material
In reality, its a diffuse and extensive duct wall thickening from tumor invasion Calculi are often rare at this level |
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Porta Hepatis Obstruction
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Usually due to neoplasm
Normal CBD and intrahepatic ductal dilation Possible GB obstruction depending on level of lesion |
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Unusual causes for bile duct dilation
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cholangiocarcinoma, Klatskins tumor, Mirizzi syndrome, choledochal cyst, biliary parasite
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Cholangiocarcinoma
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Rare malignancy, occurs in CBD or CHD
Predisposing conditions: ulcerative colitis, sclerosing cholangitis, caroli's, choledochal cyst, parasitic infection |
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Klatskins Tumor
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More specific type of cholangiocarinoma
Nonunion of the R and L hepatic ducts by the tumor invasion Intrahepatic duct dilation, local invasion of portal vein, normal pancreas, no calculi |
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Mirizzi Syndrome
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Uncommon cause for extrahepatic biliary obstruction
Cystic duct inserts unusually low into the CHD allowing the ducts to align parallel |
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Mirizzi Syndrome is caused by:
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Caused by an impacted stone in the cystic duct, creating extrinic pressure on the CHD
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Choledocal Cyst-Type 1
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Cystic fusiform dilation of the CBD
Most common form |
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Choledocal Cyst-Type 2
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A diverticulum protruding from the wall of the CBD
Rare |
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Choledocal Cyst-Type 3
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Herniation of the CBD into the duodenum
Rare Asian women, may be asymptomatic Symptomatic-pain, jaundice, mass |
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Choledochalithiasis imaging pitfalls:
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overlying bowel gas, soft pigment stone, primary tumors, 1/3 of stones are in non-dilated GB
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Detecting choledochlithiasis
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Approx 75% of stones in CBD are detectable
Stones must be seen and shown to move for dx |
