Topics

Topic

design image
Anterior cerebral artery

The anterior cerebral artery (ACA) is a paired terminal branch of the internal carotid artery (ICA), responsible for supplying the medial and superior aspects of the frontal and parietal lobes, as well as the anterior four-fifths of the corpus callosum.

It arises from the ICA just distal to its bifurcation and is divided into segments:

  • A1 (pre-communicating segment): from ICA bifurcation to anterior communicating artery (ACoA)

  • A2 (post-communicating segment): distal to ACoA, supplies medial surfaces of cerebral hemispheres

  • Distal branches: pericallosal artery and callosomarginal artery

The two ACAs are connected by the anterior communicating artery, forming a crucial part of the circle of Willis.

Clinically, ACA is vital due to its role in ischemic strokes, aneurysms at the ACoA-ACA junction, and vascular malformations. Occlusion often results in contralateral leg weakness, abulia, and behavioral changes due to frontal lobe ischemia.

Synonyms

  • ACA

  • Arteria cerebri anterior

Function

  • Supplies blood to:

    • Medial surface of frontal and parietal lobes (especially motor/sensory cortices for lower limb)

    • Anterior corpus callosum

    • Parts of basal ganglia via medial lenticulostriate arteries

  • Maintains collateral circulation via ACoA

MRI Appearance

T1-weighted images:

  • ACA lumen appears as a flow void (black tubular structure) along interhemispheric fissure

  • Vessel wall hypointense relative to brain parenchyma

T2-weighted images:

  • Flow void persists (hypointense lumen)

  • Perivascular pathology (ischemia, gliosis) appears hyperintense in ACA territory

FLAIR:

  • Normal ACA lumen not seen (signal void)

  • Acute infarcts in ACA territory show hyperintense cortical/subcortical changes

  • Chronic ischemia shows gliotic hyperintensity

T1 Post-Gadolinium (contrast-enhanced MRI):

  • Normal ACA enhances brightly and uniformly

  • Aneurysms, arteriovenous malformations, or vessel wall inflammation show focal/abnormal enhancement

MRA (Magnetic Resonance Angiography):

  • Excellent for non-invasive ACA visualization

  • Demonstrates ACA segments (A1–A2), pericallosal and callosomarginal branches

  • Detects stenosis, occlusion, aneurysms, and vascular malformations

CTA (CT Angiography):

  • High-resolution imaging of ACA origin, course, and branches

  • Depicts aneurysms at ACoA junction, distal stenosis, or occlusions

  • Provides 3D reconstructions for surgical/endovascular planning

  • Gold standard for detecting aneurysms and ischemic stroke planning

MRI images

Anterior cerebral artery axial T2 3T MRI image

MRI images

Anterior cerebral artery coronal T2 3T MRI image

MRI images

Anterior cerebral artery sagittal T2 3T MRI image

CT images

Anterior cerebral artery axial T2 3T MRI image

CT images

Anterior Cerebral Artery (ACA) ct image

CT image

Anterior cerebral artery