biliary flashcards

What is the bile flow pathway?

The bile flow pathway is: intrahepatic ducts → right & left hepatic ducts → common hepatic duct (CHD) → cystic duct joins → common bile duct (CBD) → ampulla of Vater → duodenum.

What is the Ampulla of Vater?

The Ampulla of Vater is the structure where the common bile duct (CBD) and pancreatic duct join before entering the duodenum.

What is the function of the Sphincter of Oddi?

The Sphincter of Oddi is a muscular valve that controls the flow of bile and pancreatic juice into the duodenum.

What measurement defines dilation of the common hepatic duct (CHD)?

The common hepatic duct (CHD) is considered dilated when it measures > 6 mm.

What measurement defines dilation of the common bile duct (CBD)?

The common bile duct (CBD) is considered dilated when it measures > 8 mm.

What measurement defines intrahepatic duct dilation?

Intrahepatic ducts are dilated when they measure > 2 mm OR are > 40% the diameter of the portal vein.

How are bile ducts measured on ultrasound?

Bile ducts are measured inner wall to inner wall.

When can the CBD be enlarged without pathology?

The common bile duct (CBD) may be enlarged due to aging or after cholecystectomy.

In biliary obstruction, where does dilation occur?

In biliary obstruction, ductal dilation occurs proximal (upstream) to the site of obstruction.

What is intrinsic vs extrinsic biliary obstruction?

Intrinsic obstruction = caused by something inside the duct (stone, tumor, stricture); Extrinsic obstruction = caused by external compression (e.g., pancreatic head mass).

What is the most common cause of biliary obstruction?

The most common cause of biliary obstruction is choledocholithiasis (stones in the bile duct).

What is the double-barrel sign?

The double-barrel sign is when a dilated bile duct runs parallel to the portal vein, appearing like two tubes.

What is the stellate pattern?

The stellate pattern refers to star-shaped dilation of intrahepatic bile ducts.

What are general ultrasound signs of biliary obstruction?

Ultrasound signs include duct dilation, irregular duct walls, double-barrel sign, and stellate pattern.

What is choledocholithiasis?

Choledocholithiasis is the presence of gallstones within the bile ducts, most commonly the CBD.

Where do stones in choledocholithiasis originate?

In choledocholithiasis, stones typically form in the gallbladder and migrate into the CBD.

What are classic ultrasound findings of choledocholithiasis?

Findings include: Echogenic focus, Posterior CLEAN acoustic shadowing, Proximal duct dilation.

What is a ball-valve stone?

A ball-valve stone is a stone that causes intermittent obstruction by moving within the duct.

What is cholangitis?

Cholangitis is inflammation of the bile ducts, often due to obstruction and infection.

What is primary sclerosing cholangitis (PSC)?

Primary sclerosing cholangitis (PSC) is a chronic, idiopathic inflammatory disease that causes fibrosis and narrowing of bile ducts.

What is secondary sclerosing cholangitis (SSC)?

Secondary sclerosing cholangitis (SSC) occurs due to infection, obstruction, or another underlying condition.

What does “sclerosing” mean in cholangitis?

Sclerosing refers to chronic inflammation leading to fibrosis and scarring of bile ducts.

What is pneumobilia?

Pneumobilia is the presence of air within the biliary tree.

What causes pneumobilia?

Causes include surgery, ERCP, biliary stents, fistulas, and infection.

What are ultrasound findings of pneumobilia?

Findings include: Echogenic linear foci, DIRTY shadowing, Ring-down artifact.

How do you differentiate stone vs air on ultrasound?

Stone = clean shadowing; Air (pneumobilia) = dirty shadowing + ring-down.

What is Mirizzi syndrome?

Mirizzi syndrome occurs when a stone in the cystic duct compresses the common hepatic duct (CHD).

What type of obstruction is Mirizzi syndrome?

Mirizzi syndrome causes extrinsic biliary obstruction.

What is Caroli disease?

Caroli disease is a rare condition with cystic dilation of intrahepatic bile ducts only.

What is Caroli syndrome?

Caroli syndrome includes cystic dilation + hepatic fibrosis.

What are choledochal cysts?

Choledochal cysts are congenital dilations of the bile ducts.

What is the most common type of choledochal cyst?

Type 1 choledochal cyst = extrahepatic dilation (most common).

What is the rarest type of choledochal cyst?

Type 5 choledochal cyst = multiple intrahepatic dilations (rarest).

What is cholangiocarcinoma?

Cholangiocarcinoma is a malignant tumor of the bile ducts.

What is the most important risk factor for cholangiocarcinoma?

The most important risk factor is primary sclerosing cholangitis (PSC).

What is the classic presentation of cholangiocarcinoma?

Painless jaundice, often with pruritus and weight loss.

What are ultrasound findings of cholangiocarcinoma?

Findings include mass in the duct, upstream (proximal) dilation, and altered color flow.

What is a Klatskin tumor?

A Klatskin tumor is a cholangiocarcinoma located at the junction of the right and left hepatic ducts.

What dilation pattern is seen in Klatskin tumor?

Intrahepatic duct dilation ONLY (no extrahepatic dilation).

What dilation pattern is caused by a pancreatic head mass?

A pancreatic head mass causes both intrahepatic and extrahepatic duct dilation.

What is Bouveret syndrome?

Bouveret syndrome is gastric outlet obstruction caused by a gallstone.

What is the mechanism of Bouveret syndrome?

A gallstone passes through a cholecystoenteric fistula and becomes lodged in the duodenum or stomach.

What imaging findings are seen in Bouveret syndrome?

Findings include: Ectopic gallstone, Pneumobilia, Obstruction (Rigler’s triad).

What is a biloma?

A biloma is an encapsulated collection of bile outside the biliary ducts.

What causes a biloma?

Trauma or surgery leading to bile leak.

How do you differentiate biloma from free fluid?

Biloma = encapsulated; Pericholecystic fluid = free fluid.

What is the most common cause of obstructive jaundice?

Choledocholithiasis.

What type of shadow does a gallstone produce?

Clean acoustic shadowing.

What type of shadow does pneumobilia produce?

Dirty shadowing with ring-down artifact.

What condition has the highest risk for cholangiocarcinoma?

Primary sclerosing cholangitis (PSC).

What condition presents with painless jaundice?

Cholangiocarcinoma.