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Portal vein branch to liver segment II

The portal vein branch to liver segment II is the segmental portal venous branch supplying Couinaud segment II, which is the superior portion of the left lateral hepatic section. It originates from the left portal vein, typically from its superior division, and courses cranially and laterally to enter the parenchyma of segment II.

Anatomically, it runs along with the segment II hepatic artery branch and the corresponding bile duct branch, forming the portal triad for this segment. Its distribution follows the portal segmentation principle, providing nutrient-rich blood for hepatocyte metabolism and serving as a roadmap for surgical resections.

Clinically, knowledge of the segment II portal branch is essential in hepatic resections, transplantation, and interventional procedures. Anatomical variations in size, branching pattern, and communication with segment III branches can affect surgical outcomes.

Synonyms

  • Portal branch to Couinaud segment II

  • Segment II portal vein branch

  • Left lateral superior portal branch

Function

  • Supplies nutrient-rich venous blood to segment II of the liver

  • Works with hepatic arterial supply to maintain hepatocyte function

  • Landmark for segment-oriented hepatic resections (left lateral sectionectomy)

  • Important in living donor transplantation and interventional procedures such as embolization

MRI Appearance

T1-weighted images:

  • Portal vein branch appears as a signal void (dark lumen) against liver parenchyma

  • Identifiable near the left lateral hepatic dome

T2-weighted images:

  • Lumen remains as a signal void

  • Surrounding parenchymal edema or congestion appears hyperintense

STIR:

  • Fat suppression helps delineate the vein from adjacent fat planes

  • Perivascular edema or inflammation appears bright

T1 Fat-Saturated (Pre-contrast):

  • Lumen shows intermediate signal intensity, standing out against suppressed parenchymal fat background

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Enhances homogeneously and brightly during the portal venous phase

  • Shows segmental distribution of portal inflow to segment II

MRV (Magnetic Resonance Venography):

  • Non-invasive mapping of segmental portal branches

  • Clearly demonstrates the origin of the segment II branch from the left portal vein and its intrahepatic course

  • Useful in transplant donor evaluation, resection planning, and portal vein thrombosis mapping

CT Appearance

CT Pre-Contrast:

  • Branch appears as a linear soft-tissue density, difficult to distinguish from parenchyma without contrast

CT Post-Contrast:

  • Enhances brightly during portal venous phase, delineating its intrahepatic course into segment II

  • Identifies thrombosis, stenosis, or displacement by masses

CTV (CT Venography):

  • Provides high-resolution mapping of the segment II portal vein anatomy

  • 3D reconstructions clearly show segmental distribution and branching patterns

  • Essential in living donor hepatectomy, embolization planning, and hepatic resection surgery

CT images

Portal vein branch to liver segment II axial anatomy image -img-00000-00000

CT images

Portal vein branch to liver segment II axial CT image