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Superior cerebellar artery

The Superior Cerebellar Artery (SCA) is a major vessel of the posterior circulation of the brain, supplying critical regions of the upper cerebellum, parts of the brainstem, and related structures. It is one of the three primary cerebellar arteries, the others being the anterior inferior cerebellar artery (AICA) and the posterior inferior cerebellar artery (PICA). The SCA plays a crucial role in the vascularization of the cerebellar cortex, superior vermis, deep cerebellar nuclei, and select regions of the midbrain and pons. Its location and course make it highly relevant in clinical scenarios such as cerebellar infarcts, vascular malformations, and neurovascular compression syndromes.

Synonyms

  • SCA

  • Arteria cerebelli superior (Latin)

Origin and Course

  • The SCA typically arises from the distal segment of the basilar artery, just before its bifurcation into the posterior cerebral arteries.

  • Course:

    • It courses laterally and posteriorly, wrapping around the brainstem just below the oculomotor nerve (cranial nerve III).

    • Passes superior to the cerebellar peduncle and beneath the tentorium cerebelli.

    • It runs close to the trigeminal nerve (cranial nerve V), and variations in its course can be associated with trigeminal neuralgia.

    • The artery then divides into superior and inferior branches that supply the superior surface of the cerebellum and parts of the midbrain.

Function (Vascular Territory)

  • Supplies the superior aspect of the cerebellar hemispheres.

  • Provides blood to the superior vermis and deep cerebellar nuclei (especially the dentate nucleus).

  • Vascularizes portions of the superior cerebellar peduncle, dorsolateral pons, and rostral midbrain.

  • Small perforating branches supply parts of the brainstem.

MRI Appearance

  • On MR angiography (MRA):

    • The SCA can be visualized as a paired, thin vessel branching from the upper basilar artery.

    • Appears as a flow void (dark signal) on routine T2-weighted images due to rapid blood flow.

    • Enhanced MR sequences (contrast-enhanced MRA or TOF MRA) can delineate its course and any vascular pathology (e.g., aneurysm, occlusion).

  • On diffusion-weighted imaging (DWI):

    • SCA infarction will show restricted diffusion in its territory, mainly the superior cerebellar hemisphere.

CT Appearance

  • On CT Angiography (CTA):

    • The SCA appears as a small-caliber vessel emerging from the terminal basilar artery, best visualized in thin-slice arterial phase images.

    • May be challenging to distinguish from adjacent vessels unless high-resolution imaging is used.

  • On Non-contrast CT (NCCT):

    • The vessel itself is usually not visualized, but infarction in the SCA territory will appear as hypodensity in the superior cerebellum.

    • Early infarction may be subtle; late-stage infarct is seen as well-demarcated low-density area in the SCA distribution.

MRI image

Superior cerebellar artery MRI 3T coronal t2 image

CT image

Superior cerebellar artery CT coronal anatomy image -img-00001-00001