Choroid Plexus: Normal Locations and Appearances

Abstract

The choroid plexus (CP) can be seen anywhere throughout the ventricular system with the exception of the cerebral aqueduct. It consists of numerous capillary-rich villi (with a blood flow of nearly ten times that of the cerebral cortex), which in turn are composed of a type of ependymal cells. The purpose of the choroid is to serve as a sort of filtration system for the ventricular system and the cerebrospinal fluid (CSF). The most apparent location of the CP is the glomus, located within the trigones (atria) of the lateral ventricles. The CP is typically contiguous through the ventricular system, although this may not be apparent on thicker images in a single plane. While the CP can be present throughout the ventricular system, regions that are normal locations for the CP but that may be unusual to see on imaging within the third or fourth ventricles include the temporal horns of the lateral ventricles, the choroidal fissures, the foramina of Monro, the foramina of Luschka, the cerebellopontine angles, or even the foramen of Magendie (i.e., the median aperture).