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Paracentral artery

The paracentral artery is a small but clinically significant branch of the anterior cerebral artery (ACA). It is primarily responsible for supplying blood to the paracentral lobule, a region of the brain’s medial surface that is involved in motor and sensory functions of the lower extremity. Its course, distribution, and imaging appearances are important to understand, especially in neurovascular and neuroimaging contexts.

Synonyms

  • Paracentral lobule artery

  • Paracentral branch of the anterior cerebral artery

  • Superior internal parietal artery (occasionally, in anatomical literature)

Origin and Course

  • The paracentral artery typically arises from the pericallosal artery, a terminal branch of the anterior cerebral artery (ACA), most commonly from the A3 segment.

  • After originating from the pericallosal artery, it courses superiorly and posteriorly along the medial surface of the cerebral hemisphere.

  • It mainly supplies the paracentral lobule, a region located on the medial aspect of the cerebral hemisphere, at the junction of the precentral and postcentral gyri.

  • The artery often anastomoses with adjacent cortical branches from the ACA and, to a lesser extent, with branches from the posterior cerebral artery (PCA).

Function

  • The paracentral artery is responsible for supplying blood to the paracentral lobule.

  • This lobule contains the cortical representation for the motor and sensory innervation of the contralateral lower limb (leg and foot).

  • Infarction or compromise of this artery can lead to contralateral motor and sensory deficits of the lower extremity, including paraplegia or sensory loss in the leg.

MRI Appearance

  • On MR angiography (MRA), the paracentral artery appears as a small cortical branch extending superiorly and posteriorly from the pericallosal artery.

  • In cases of infarction (ischemic stroke), MRI (especially DWI and FLAIR sequences) may show restricted diffusion or hyperintensity in the paracentral lobule, corresponding to the territory supplied by the paracentral artery.

  • On contrast-enhanced MR angiography, the artery may be visualized as a fine vessel branching from the pericallosal artery.

  • Subtle infarcts in its territory may be missed on non-contrast MRI, emphasizing the need for high-resolution imaging.

CT Appearance

  • The paracentral artery itself is generally not directly visible on non-contrast CT due to its small size.

  • On CT angiography (CTA), it may be visualized as a fine cortical branch from the pericallosal artery, though often requires multiplanar reformatting.

  • Acute infarcts in the paracentral lobule will appear as hypodense regions on non-contrast CT, correlating with the area supplied by the paracentral artery.

  • CT perfusion imaging may show decreased perfusion in the paracentral lobule in the setting of paracentral artery occlusion.

MRI image

Paracentral artery MRI 3T sagittal image

CT image

Paracentral artery ct image