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Portal vein branch to liver segment VI

The portal vein branch to liver segment VI is a terminal tributary of the right posterior portal vein, which itself arises from the right portal vein. Segment VI lies in the posterior inferior portion of the right lobe, bounded superiorly by segment VII, anteriorly by segment V, and medially by segment VIII.

The branch usually arises as one of the inferior subdivisions of the posterior sectoral portal vein, running obliquely toward the posterior-inferior aspect of the right lobe. It supplies the hepatic parenchyma of segment VI with portal venous blood, which constitutes around 70–80% of its total blood inflow.

This vessel is clinically important in hepatic surgery, segmental resection, interventional radiology, and liver transplantation, where precise mapping of segmental vascular anatomy is critical to preserve functional parenchyma and avoid ischemic complications.

Synonyms

  • Segment VI portal vein branch

  • Right posterior inferior portal vein branch

  • Portal tributary to posterior right lobe

Function

  • Provides portal venous inflow to segment VI (posterior-inferior right lobe)

  • Contributes to nutrient-rich hepatic circulation alongside arterial inflow

  • Serves as a surgical landmark in right hepatectomy, segmentectomy, and transplant donor evaluation

MRI Appearance

T1-weighted images:

  • Portal vein branch appears as a flow void (dark tubular structure) within hepatic parenchyma

  • Surrounded by intermediate signal liver tissue

T2-weighted images:

  • Vessel lumen appears as a signal void; adjacent pathology (edema, congestion) may appear hyperintense

STIR:

  • Fat suppression enhances conspicuity of portal venous structures

  • Highlights perivascular edema or infiltration

T1 Fat-Saturated (Pre-contrast):

  • Lumen may appear intermediate signal intensity against suppressed fat background

  • Enhances differentiation from parenchymal tissue

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Segment VI portal branch enhances brightly during the portal venous phase

  • Demonstrates clear anatomy and drainage area within posterior right lobe

MRV (Magnetic Resonance Venography):

  • Depicts right posterior portal system and terminal branch to segment VI

  • Provides 3D mapping of intrahepatic portal venous anatomy

  • Used in transplant donor evaluation, tumor planning, and venous obstruction workup

CT Appearance

CT Pre-Contrast:

  • Branch appears as a faint linear soft-tissue structure within right lobe parenchyma

  • Limited visualization without contrast

CT Post-Contrast:

  • Bright enhancement of segment VI branch during portal venous phase

  • Useful for identifying patency, thrombosis, or anatomical variants

CTV (CT Venography):

  • Gold standard for segmental portal vein mapping

  • 3D reconstructions show the origin from right posterior portal vein, course to segment VI, and branching pattern

  • Critical for segmental resection, transplant planning, and vascular pathology assessment

Portal vein branch to liver segment VI CT axial image 0

Portal vein branch to liver segment VI CT axial image 1

Portal vein branch to liver segment VI CT axial image 2