Glomus of the choroid plexus: the normal spin-echo appearance on magnetic resonance imaging.

The glomus of the choroid plexus is located within the trigone of the lateral ventricles. The magnetic resonance images of the choroid plexus in 624 patients of all ages were reviewed and graded to determine the variation of the appearance of the glomus of the choroid plexus as seen on T2-weighted spin echo (SE). With the moderately T2-weighted SE sequences the intensity of the choroid plexus signal was equal to, or less than, that from deep cerebral grey matter in 76% of patients and greater than that from deep cerebral grey matter in 23%; in 1% of patients the glomus of the choroid plexus was "cyst-like". In all 100 patients studied with the heavily T2-weighted SE sequence the intensity of the choroid plexus signal was greater than that from the deep cerebral grey matter. The variation in the normal appearance of the glomus of the choroid plexus is consistent with known histologic changes described in the literature. The importance of recognizing the glomus of the choroid plexus and not mistaking it for other normal anatomical structures or diseases is evident.