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Precuneal artery

The precuneal artery is a small but significant cortical branch of the cerebral vasculature, primarily arising from the pericallosal artery, itself a major branch of the anterior cerebral artery (ACA). It supplies the medial aspect of the parietal lobe, specifically the precuneus, which plays a crucial role in various cognitive functions such as visuospatial imagery, episodic memory retrieval, and aspects of consciousness. Despite its relatively small size, the artery is vital for maintaining the metabolic demands of this important cortical region. Understanding its anatomy is essential in neuroimaging and neurosurgical procedures, especially given its involvement in certain ischemic events and during the planning of interhemispheric surgical approaches.

Synonyms

  • Precuneal branch of the anterior cerebral artery

  • Arteria precunealis (Latin)

  • Medial parietal artery (less commonly used)

Origin and Course

  • Origin:

    • Arises from the pericallosal artery, which is the terminal branch of the anterior cerebral artery (ACA), usually from the A2 or A3 segment.

  • Course:

    • Courses dorsally and posteriorly along the medial aspect of the cerebral hemisphere.

    • Follows the surface of the precuneus, supplying its cortex.

    • May anastomose with adjacent branches such as the paracentral and posterior internal parietal arteries.

    • Occasionally, accessory branches may arise from the callosomarginal artery.

Function

  • Supplies blood to the precuneus, an area involved in:

    • Visuospatial processing

    • Self-referential mental activity

    • Episodic memory retrieval

    • Aspects of consciousness and awareness

MRI Appearance

  • Not directly visualized as a named vessel on standard MRI sequences due to its small size.

  • MR Angiography (MRA):

    • May visualize as a small branch arising from the pericallosal artery.

    • Enhanced in high-resolution 3D TOF (Time-of-Flight) MRA or AI enhanced 3T images. 

  • Indirect findings:

    • Infarcts in the vascular territory of the precuneal artery may appear as wedge-shaped or cortical signal abnormalities in the medial parietal lobe.

CT Appearance

  • Generally not individually visualized on routine non-contrast CT due to its small caliber.

  • CT Angiography (CTA):

    • Can sometimes be identified as a thin cortical branch from the pericallosal artery with high-resolution imaging.

  • Indirect findings:

    • Ischemic events involving the artery may present as focal hypodensity in the medial parietal cortex (precuneus region).

    • In cases of hemorrhage or vascular malformations, the vascular territory may be highlighted by contrast extravasation or abnormal vessels.

MRI images

Precuneal artery MRI 3T sagittal image 1

MRI images

Precuneal artery MRI 3T sagittal image

CT image

Precuneal artery CT sagittal anatomy image -img-00001-00001