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Portal vein branch to liver segment V

The portal vein branch to segment V (also called the segment V portal vein) is a segmental branch of the right portal vein, which arises from the bifurcation of the main portal vein into right and left divisions. The right portal vein further divides into anterior and posterior branches. The anterior branch supplies segments V and VIII, and from this arises the segment V portal vein branch, which courses inferiorly to supply the liver tissue of segment V, located in the anteroinferior portion of the right hepatic lobe (below the horizontal plane of the portal vein, anterior to the gallbladder fossa).

Segment V represents a key surgical and interventional landmark because of its relationship to the gallbladder, middle hepatic vein, and right anterior portal system. Precise mapping of the segment V portal vein is critical in hepatic resections, segmental hepatectomy, transplantation, and interventional radiology procedures such as portal vein embolization.

Synonyms

  • Segment V portal branch

  • Portal branch to right anterior inferior segment

  • Intrahepatic portal vein branch to segment V

Function

  • Delivers nutrient-rich blood from the portal circulation to liver segment V

  • Works with hepatic arteries to provide dual blood supply

  • Drains into intrahepatic sinusoids, which return blood via hepatic veins to the IVC

  • Serves as an important anatomical and surgical landmark in hepatobiliary surgery

MRI Appearance

T1-weighted images:

  • Appears as a flow void (dark tubular structure) within the anteroinferior right hepatic lobe

  • Surrounded by intermediate parenchymal signal

T2-weighted images:

  • Also appears as a signal void; pathology such as thrombus would appear intermediate to hyperintense

  • Adjacent liver parenchymal edema appears hyperintense

STIR:

  • Suppresses fat, improving visualization of parenchymal changes around the vein

  • Venous lumen itself remains a signal void

T1 Fat-Saturated (Pre-contrast):

  • Lumen shows intermediate signal intensity against suppressed fat background

  • Improves detection of vascular structures relative to surrounding tissue

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Segment V portal branch enhances brightly and homogeneously during the portal venous phase

  • Clearly delineates its course from the right anterior portal vein into segment V

MRV (Magnetic Resonance Venography):

  • Demonstrates the origin from the right anterior portal branch and inferior course into segment V

  • Provides 3D vascular mapping, useful for surgical planning and portal embolization procedures

  • Detects stenosis, thrombosis, or anomalous branching patterns

CT Appearance

CT Pre-Contrast:

  • Appears as a small soft-tissue density structure in segment V

  • Difficult to distinguish without contrast

CT Post-Contrast:

  • Enhances in the portal venous phase, showing the portal branch coursing to segment V

  • Useful for identifying thrombosis, stenosis, or collateral circulation

CTV (CT Venography):

  • Gold standard for high-resolution vascular mapping

  • 3D reconstructions clearly demonstrate the origin, course, and branching of the segment V portal vein

  • Essential in donor liver surgery, right anterior segmentectomy, and embolization planning

CT images

Portal vein branch to liver segment V CT axial image 1

CT images

Portal vein branch to liver segment V CT axial image 2

CT images

Portal vein branch to liver segment V CT axial image