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Pancreatic duct

The pancreatic duct, also called the duct of Wirsung, is the main duct of the pancreas. It runs the length of the pancreas, collecting exocrine secretions and delivering them to the duodenum. The duct typically joins the common bile duct to open into the second part of the duodenum at the major duodenal papilla (ampulla of Vater), though anatomical variations are common.

This duct is vital in digestion, as it carries pancreatic enzymes essential for fat, protein, and carbohydrate breakdown. It is a key focus in imaging and surgery due to its involvement in pancreatitis, tumors, and congenital anomalies.

Synonyms

  • Duct of Wirsung

  • Main pancreatic duct

  • Primary exocrine duct of pancreas

Origin, Course, and Termination

  • Origin: Arises from smaller tributary ducts within the pancreatic tail

  • Course: Runs from the tail through the body to the head of the pancreas, generally near the posterior surface of the gland

  • Termination: Joins the common bile duct to open at the major duodenal papilla (ampulla of Vater) in the second part of the duodenum; may have accessory connections with the duct of Santorini (accessory pancreatic duct)

Relations

  • Anteriorly: Stomach and transverse colon

  • Posteriorly: Splenic vein, superior mesenteric vessels, aorta, and vertebral column

  • Laterally: Duodenum (right), spleen (left)

  • Inferiorly: Jejunum and mesentery

Function

  • Transports pancreatic exocrine secretions (enzymes and bicarbonate) into the duodenum

  • Works with the common bile duct to deliver bile and enzymes for digestion

  • Contributes to neutralization of gastric acid and digestion of fats, proteins, and carbohydrates

Clinical Significance

  • Chronic pancreatitis: Causes ductal strictures, irregularities, and dilatation

  • Pancreatic duct stones: Can obstruct outflow, causing recurrent pancreatitis

  • Pancreatic carcinoma: Often arises in the head, producing abrupt ductal narrowing ("double duct sign" with CBD)

  • Congenital anomalies: Pancreas divisum (failure of duct fusion) alters drainage pattern

  • Surgical relevance: Evaluated in Whipple procedures and pancreaticojejunostomy

MRI Appearance

T1-weighted images:

  • Pancreatic duct appears as a thin linear low-signal structure within pancreatic tissue

  • Difficult to visualize unless dilated

T2-weighted images:

  • Duct fluid appears bright signal

  • Normal duct: thin bright line; dilated duct: tubular high-signal structure

  • Wall: thin hypointense rim

STIR (Short Tau Inversion Recovery):

  • Fluid: bright hyperintense

  • Periductal inflammation: bright signal in surrounding parenchyma

  • Fat: suppressed, improving duct visualization

T1 Fat-Sat Post-Contrast:

  • Normal duct lumen does not enhance

  • Wall may show minimal enhancement

  • Pathology (strictures, tumor infiltration): irregular wall enhancement

T2 Fat-Saturated HASTE:

  • Duct lumen: very bright linear/tubular structure across pancreas

  • Stones: dark intraluminal filling defects

  • Excellent for rapid survey of ductal anatomy and obstruction

T2 TSE Fat-Saturated 3D (MRCP):

  • Duct shows continuous bright high-signal intensity

  • Allows full 3D reconstruction of pancreaticobiliary tree

  • Useful for detecting strictures, stenosis, and anatomical variants (e.g., pancreas divisum)

Thick-slab T2 Fat-Saturated HASTE:

  • Displays duct as a bright tubular structure in projectional MRCP view

  • Stones and strictures appear as dark or interrupted segments

  • Provides quick overview of entire duct and its relation to CBD

CT Appearance

Non-Contrast CT:

  • Normal duct: difficult to visualize unless dilated

  • Appears as a thin hypodense line in the pancreas

  • Pancreatic calcifications may indicate chronic pancreatitis

Post-Contrast CT:

  • Normal duct: non-enhancing tubular structure within enhancing pancreatic parenchyma

  • Dilated duct: easily seen as fluid-density structure

  • Pathology: abrupt cut-off in carcinoma, irregular narrowing in chronic pancreatitis, rim-enhancing collections in infection/abscess

MRI image

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MRI image

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MRI image

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