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Hepatopancreatic ampulla (ampulla of Vater)

The hepatopancreatic ampulla, also known as the ampulla of Vater, is the dilated terminal portion where the common bile duct (CBD) and the main pancreatic duct (duct of Wirsung) merge before opening into the duodenum. It is located in the wall of the second part of the duodenum and opens at the major duodenal papilla.

This structure regulates the flow of bile and pancreatic juice into the duodenum through the sphincter of Oddi. Its small size and critical role in bile and pancreatic drainage make it a key site for pathologies, including stones, strictures, and ampullary tumors.

Synonyms

  • Ampulla of Vater

  • Choledochopancreatic ampulla

  • Duodenal ampulla

Location and Structure

  • Found in the medial wall of the second (descending) part of the duodenum

  • Formed by the union of the common bile duct and main pancreatic duct

  • Surrounded by the sphincter of Oddi (smooth muscle complex regulating flow)

  • Opens at the major duodenal papilla into the duodenal lumen

Relations

  • Anteriorly: Duodenal lumen

  • Posteriorly: Head of pancreas

  • Superiorly: Terminal portion of CBD

  • Inferiorly: Main pancreatic duct

Function

  • Regulates flow of bile and pancreatic secretions into the duodenum

  • Prevents reflux of duodenal contents into the bile and pancreatic ducts

  • Coordinates with digestive activity for fat digestion and enzyme activation

Clinical Significance

  • Choledocholithiasis: Stones may lodge at the ampulla, causing obstructive jaundice or pancreatitis

  • Ampullary tumors (ampullary carcinoma): Malignant obstruction site with high surgical importance

  • Sphincter of Oddi dysfunction: May cause biliary colic and recurrent pancreatitis

  • Obstruction: Leads to double-duct sign (dilatation of both CBD and pancreatic duct)

  • Endoscopy relevance: Landmark for ERCP procedures

MRI Appearance

T1-weighted images:

  • Ampulla lumen: dark (low signal) due to bile/pancreatic fluid

  • Surrounding duodenal wall and sphincter: intermediate signal

T2-weighted images:

  • Lumen: bright (high signal) due to bile and pancreatic secretions

  • Wall/sphincter: hypointense thin ring

STIR (Short Tau Inversion Recovery):

  • Lumen: bright fluid signal

  • Fat planes: suppressed, improving duct/ampulla delineation

T1 Fat-Sat Post-Contrast:

  • Normal ampullary wall: mild thin rim enhancement

  • Ampullary tumors or inflammation: heterogeneous or nodular enhancement

T2 Fat-Saturated HASTE (single-shot):

  • Ampulla lumen: very bright signal

  • Excellent for rapid detection of obstruction or filling defects (stones, tumors, sludge)

T2 TSE Fat-Saturated 3D (MRCP):

  • Ampulla visualized as terminal convergence of CBD and pancreatic duct

  • Appears bright as part of biliary–pancreatic tree

  • Allows multiplanar reconstruction and evaluation of strictures or masses

Thick-slab T2 Fat-Saturated HASTE:

  • Ampulla seen as part of continuous bright column of biliary and pancreatic ducts

  • Useful for overview MRCP images in a single slice

  • Filling defects appear dark against bright fluid

CT Appearance

Non-Contrast CT:

  • Ampulla difficult to visualize unless dilated

  • Stones: may appear as hyperdense foci

  • Surrounding soft tissue may obscure normal ampulla

Post-Contrast CT:

  • Ampullary wall enhances subtly

  • Tumors appear as enhancing soft tissue masses at duodenal papilla

  • Obstruction seen as upstream dilation of CBD and pancreatic duct (“double-duct sign”)

  • Inflammation may cause mural thickening and peripancreatic fat stranding

MRI image

Hepatopancreatic ampulla (ampulla of Vater) mri coronal anatomy image-img-00000-00000

MRI image

Hepatopancreatic ampulla (ampulla of Vater) mri coronal anatomy image-img-00000-00000_00001