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Medial orbitofrontal artery

The medial orbitofrontal artery is a cortical branch of the anterior cerebral artery (ACA), usually arising from the A2 segment. It courses anteriorly and inferiorly along the gyrus rectus and medial orbital surface of the frontal lobe, supplying the medial orbitofrontal cortex. This cortical territory is involved in decision-making, reward processing, and emotional regulation. The artery forms anastomoses with branches of the lateral orbitofrontal artery (from MCA) and other small ACA cortical branches, contributing to collateral blood supply in the frontal base.

Synonyms

  • Orbitofrontal branch of ACA (medial)

  • Medial frontal orbital artery

  • Medial orbital branch of anterior cerebral artery

Function

  • Supplies blood to the medial orbitofrontal cortex and gyrus rectus

  • Provides perfusion to regions involved in cognition, decision-making, and emotional processing

  • Contributes to collateral circulation with lateral orbitofrontal and ACA/MCA border zone arteries

  • Helps maintain frontal lobe perfusion during vascular compromise

MRI Appearance

T1-weighted images (non-contrast):

  • Appears as a flow void (signal loss) within sulci of the orbitofrontal cortex

  • Not directly visualized without angiographic sequences

T2-weighted images:

  • Vessel lumen also appears as a flow void against hyperintense CSF in nearby sulci

  • Adjacent cortical hyperintensity may indicate ischemia or encephalomalacia in orbitofrontal infarcts

MRA (Magnetic Resonance Angiography):

  • Time-of-flight (TOF) and contrast-enhanced MRA clearly depict the origin from A2, anterior course, and cortical branches

  • Normal artery appears as a bright, enhancing lumen

  • Excellent for evaluating stenosis, occlusion, aneurysm, or small-vessel malformations

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • Vessel lumen enhances strongly

  • Helpful when combined with MRA for visualizing cortical branches in fine detail

CT Appearance

Non-contrast CT:

  • Artery is not directly seen

  • Acute thrombosis may appear as a hyperdense cortical artery sign in orbitofrontal sulci

CT Angiography (CTA):

  • Provides excellent visualization of the origin from ACA (A2), course over the gyrus rectus, and distribution to medial orbitofrontal cortex

  • Opacified with contrast, allowing assessment of stenosis, occlusion, aneurysm, or AVM

  • CTA is particularly useful in stroke evaluation, surgical planning, and aneurysm detection

MRI images

Medial orbitofrontal artery