This document provides an overview of the radiological anatomy of the biliary system. It describes the components of the biliary apparatus including the gallbladder, cystic duct, hepatic ducts and common bile duct. It details the blood supply, nerve supply and lymphatic drainage of the gallbladder. It also describes how the biliary tree appears on various medical imaging modalities like ultrasound, MRI, CT, ERCP, and cholangiography. These modalities can be used to visualize the intrahepatic and extrahepatic biliary structures.
2. BILIARY APPARATUS
Consists of:
• Gallbladder
• Cystic duct
• Right and Left Hepatic Ducts
which unite to form common
hepatic duct.
• Common Bile Duct
3. GALL BLADDER
• The gallbladder is a pear-shaped
musculomembranous sac located
along the undersurface of the liver.
• The gallbladder communicates with
the rest of the biliary system by way
of the cystic duct, with bidirectional
drainage of bile to and from the
common hepatic duct.
5. • Parasympathetic is by pre-
ganglionic fibres from the vagus
nerve.
• Sympathetic is from post-ganglionic
fibres of coeliac plexus.
NERVE SUPPLY OF GALLBLADDER
6. LYMPHATICS OF GALLBLADDER
• Cholecysto-retropancreatic: following common duct inferiorly to a retroportal node
posterior to pancreatic head (primary pathway)
• Cholecysto-celiac: via hepatoduodenal ligament to celiac nodes
• Cholecysto-mesenteric: anterior to portal vein to superior mesenteric root nodes
17. EXTRA-HEPATIC BILIARY TREE
• Consists of Cystic duct and common
bile duct.
• CBD Diameter: <6mm but maybe
larger in elderly patients.
• CBD length: 7 to 8 cm
23. CT CHOLANGIOGRAPHY
• CT cholangiography is a technique of imaging the biliary tree with the usage of
hepatobiliary excreted contrast.
• CT cholangiography may be performed with either intravenous or oral
cholangiographic contrast agents both of which outline the biliary tree with
positive contrast.
Normal Gall-Bladder Wall Thickness: <3mm
Normal Gall Bladder length: 7-12cm
Transverse diameter of Gall Bladder: 3-4 cm
Right Hepatic Duct branches into right posterior hepatic duct which drains posterior segments VI and VII and right anterior hepatic duct which drains anterior segments V and VIII.
Segmental tributaries draining segments II to IV are form left hepatic duct.
Supraduodenal portion: About 2.5 cm long, running in the free edge of the lesser omentum.
Retroduodenal portion.
Infraduodenal portion lies in a groove, but at times in a tunnel, on the posterior surface of the pancreas.
Intraduodenal portion passes obliquely through the wall of the second part of the duodenum, where it is surrounded by the sphincter of Oddi, and terminates by opening on the summit of the ampulla of Vater.
Short Axis(Transverse View) Mickey Mouse View
CBD is anterior to the Portal vein and doesn’t take up any flow on doppler.
Portal Vein can be identified by hyperechoic walls surrounding the vein. This is due to presence of connective tissue around the portal vein.
Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic and interventional procedure technique using both endoscopy and fluoroscopy for examination and intervention of the biliary tree and pancreatic ducts.
It involves passing an endoscope to the descending duodenum and subsequently cannulating the ampulla of vater, after which contrast can be injected outlining the biliary tree and various procedures can be performed.
Axial CT Cholangiogram: Cranial to Caudal.
Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging technique to visualize the intra and extrahepatic biliary tree and pancreatic ductal system.
MRCP is performed on a 1.5 T or superior MRI system, using a phased-array body coil.
All protocols obtain heavily T2-weighted sequences
A T-tube cholangiogram is a fluoroscopic procedure in which contrast medium is injected through a T-tube into the patient's biliary tree. The T-tube is most commonly inserted during a cholecystectomy operation when there is a possibility of residual gall stones within the biliary tree.
This technique has been largely superseded by MRCP and ERCP.
Typically a T-shaped tube is left in the common bile duct at the time of surgery (e.g. cholecystectomy) and allows for exploration of the common bile duct (choledochotomy) and retrieval of common bile duct stones. At a later date (usually approximately 10 days), imaging of the biliary tree (cholangiogram) is performed via the tube.