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Portal vein branch to liver segment VIII

The portal vein branch to liver segment VIII (PV8) is the segmental branch of the right anterior portal vein that supplies blood to segment VIII of the liver, according to Couinaud’s classification. Segment VIII is located in the anterosuperior portion of the right hepatic lobe, above segment V, between the middle hepatic vein (medially) and the right hepatic vein (laterally).

The branch arises from the anterior division of the right portal vein, typically as a superior branch to segment V. It courses superiorly within the right hepatic lobe and ramifies to perfuse the anterosuperior parenchyma. Variations are common, with segment VIII sometimes receiving accessory supply from neighboring segmental branches.

This vessel is critically important in hepatic resections, transplant donor surgeries, and interventional radiology procedures (e.g., TIPS, embolization), since preservation or ligation alters perfusion of the superior right lobe.

Synonyms

  • Portal vein branch to segment VIII (PV8)

  • Segment VIII portal vein branch

  • Right anterior superior portal vein branch

Function

  • Supplies portal venous blood (nutrient-rich blood from intestines) to segment VIII of the liver

  • Contributes to hepatic microcirculation and metabolism in the right anterior superior lobe

  • Serves as a surgical and radiologic landmark in Couinaud’s liver segmentation

MRI Appearance

T1-weighted images:

  • PV8 appears as a flow void (dark tubular structure) within segment VIII parenchyma

  • Surrounded by intermediate-signal hepatic tissue

T2-weighted images:

  • Lumen appears as dark signal void; liver parenchyma shows intermediate signal

  • Pathology (e.g., thrombosis) may show altered intraluminal signal

STIR:

  • Suppresses fat, improving vessel conspicuity within hepatic parenchyma

  • Perivascular edema or inflammation appears hyperintense

T1 Fat-Saturated (Pre-contrast):

  • Vessel lumen appears as intermediate signal intensity, standing out against suppressed hepatic fat background

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Enhances brightly during the portal venous phase

  • Defines PV8 course and branching within segment VIII

  • Detects thrombosis, stenosis, or abnormal neovascularization

MRV (Magnetic Resonance Venography):

  • Non-invasive mapping of portal venous system

  • Clearly depicts PV8 origin from right anterior portal vein and intrasegmental distribution

  • Used in pre-surgical planning, transplant evaluation, and portal hypertension

CT Appearance

CT Pre-Contrast:

  • PV8 appears as a small hypodense linear structure in liver parenchyma

  • Rarely visualized clearly without contrast

CT Post-Contrast (Portal Venous Phase):

  • Enhances brightly and homogeneously as part of portal system

  • Defines branching pattern within segment VIII

  • Detects filling defects (thrombus), stenosis, or collaterals

CTV (CT Venography):

  • Provides detailed 3D visualization of PV8 and its relationship to adjacent portal branches

  • Essential for Couinaud segment mapping, donor hepatectomy planning, and interventional radiology

  • Identifies anatomic variations critical for safe resection or embolization

CT images

Portal vein branch to liver segment VIII CT axial image 0

CT images

Portal vein branch to liver segment VIII CT axial image 1

CT images

Portal vein branch to liver segment VIII CT axial image 2