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Choroid plexus of fourth ventricle

The choroid plexus of the fourth ventricle is a delicate, highly vascular structure found within the roof of the fourth ventricle of the brain. It plays a critical role in the production of cerebrospinal fluid (CSF). The choroid plexus in this location is characterized by its convoluted, villous appearance and is lined by ependymal cells. It extends from the lateral recesses of the fourth ventricle medially, forming a "T" shaped configuration when viewed from above. Its anatomical position makes it important in both physiological and pathological processes affecting the posterior fossa and ventricular system.

Arterial Supply

  • Primarily supplied by the posterior inferior cerebellar artery (PICA).

  • Additional minor branches may arise from the anterior inferior cerebellar artery (AICA).

  • Fine branches pierce the tela choroidea to supply the choroid plexus tissue.

Venous Drainage

  • Venous drainage is mainly via the veins of the fourth ventricle, which drain into the internal cerebral veins and vein of Galen.

  • Some venous blood may also drain toward the superior petrosal sinus via cerebellar veins.

Function

  • The primary function is production of cerebrospinal fluid (CSF).

  • Helps maintain the chemical stability and homeostasis of the CNS environment.

  • Acts as a barrier and site for exchange between blood and CSF (part of the blood-CSF barrier).

  • Involved in the removal of metabolic waste from the brain.

MRI Appearance

  • T1-weighted imaging:

    • Choroid plexus appears isointense to mildly hypointense relative to brain parenchyma.

    • May show enhancement after gadolinium contrast administration due to its vascularity.

  • T2-weighted imaging:

    • Choroid plexus is typically hyperintense compared to brain tissue.

    • Signal may be heterogeneous due to vascularity and flow voids.

  • FLAIR imaging:

    • Appears intermediate to mildly hyperintense; CSF suppression on FLAIR accentuates the choroid plexus relative to the ventricle.

    • Calcifications (if present) may appear hypointense.

CT Appearance

  • Choroid plexus appears as a soft tissue density structure within the roof and lateral recesses of the fourth ventricle.

  • Calcifications are common, especially in adults and elderly, and appear as high-density foci.

  • Contrast-enhanced CT: choroid plexus enhances due to its vascular nature.

MRI images

choroid plexus of fourth ventricle mri 3t axial image