Topics

Topic

design image
Lateral branch of left hepatic duct

The lateral branch of the left hepatic duct is one of the major intrahepatic biliary tributaries. It drains bile from the lateral (segments II and III) of the left hepatic lobe, before uniting with the medial branch of the left hepatic duct. Together, these branches form the left hepatic duct, which then joins the right hepatic duct to form the common hepatic duct.

This duct is clinically important because it is frequently involved in liver resections, biliary reconstructions, and transplantation surgery, and is a key site in radiologic evaluation of intrahepatic biliary obstruction.

Synonyms

  • Lateral segmental duct of left lobe

  • Segment II/III bile duct

  • Peripheral lateral left hepatic duct

Origin, Course, and Termination

  • Origin: Arises from intrahepatic bile canaliculi draining segments II and III (left lateral sector) of the liver

  • Course: Runs medially within the left lobe parenchyma, converging toward the hepatic hilum within the Glisson’s sheath

  • Termination: Joins the medial branch of the left hepatic duct to form the left hepatic duct, which then unites with the right hepatic duct to create the common hepatic duct

Relations

  • Anteriorly: Liver parenchyma of segments II and III

  • Posteriorly: Branches of the left portal vein

  • Superiorly: Left hepatic artery branches

  • Inferiorly: Approaches the porta hepatis and merges into left hepatic duct proper

Function

  • Collects bile from hepatocytes of the left lateral liver sector (segments II and III)

  • Channels bile into the left hepatic duct and subsequently into the common hepatic duct and common bile duct

  • Provides a critical conduit for bile drainage during normal physiology and after hepatic surgery

Clinical Significance

  • Segmental resections: Identification of lateral branch essential during segment II or III hepatectomy

  • Biliary strictures: May occur postoperatively (e.g., after left hepatectomy or living donor transplant)

  • Cholangiocarcinoma: Peripheral bile duct tumors may involve this branch

  • Interventional radiology: Frequently targeted in percutaneous transhepatic biliary drainage (PTBD)

  • Anatomic variation: Variants in its course or union with the medial branch are common and surgically significant

MRI Appearance

T1-weighted images:

  • Lumen: low signal (fluid-filled)

  • Wall: thin and low signal, may enhance if inflamed or neoplastic

T2-weighted images:

  • Lumen: high signal intensity (bright)

  • Wall: low signal thin outline

  • Obstruction: dilatation with bright intraductal fluid

STIR (Short Tau Inversion Recovery):

  • Lumen: hyperintense fluid signal

  • Fat suppressed, highlighting duct against liver parenchyma

T1 Fat-Sat Post-Contrast:

  • Duct wall: minimal or no enhancement in normal duct

  • Pathology: mural enhancement in cholangitis, irregular enhancement in cholangiocarcinoma

T2 Fat-Saturated HASTE (single-shot):

  • Duct lumen: very bright hyperintense signal

  • Excellent for rapid depiction of biliary anatomy

  • Stones: dark filling defects within bright bile

T2 TSE Fat-Saturated 3D (MRCP):

  • Lateral branch: sharply depicted as a bright tubular structure draining segments II and III

  • Allows 3D reconstruction of intrahepatic and extrahepatic ducts

  • Detects strictures, dilatation, or intraductal pathology

Thick-slab T2 Fat-Saturated HASTE:

  • Lateral branch visible as part of bright projectional MRCP image

  • Provides global overview of biliary tree

  • Filling defects (stones, air) appear as dark voids within bright lumen

CT Appearance

Non-Contrast CT:

  • Normally not well visualized unless dilated

  • Dilated ducts appear as hypoattenuating tubular structures in the left lobe parenchyma

Post-Contrast CT:

  • Bile ducts enhance minimally

  • Dilated ducts remain low-attenuation channels

  • Wall thickening, mural enhancement, or periductal infiltration suggest inflammatory or malignant pathology

MRI image

Lateral branch of left hepatic duct mri coronal anatomy image-img-00000-00000