What is the main abnormality demonstrated on the right?
'Close lipped' schizencephaly.
Bilateral polymicrogyria is demonstrated involving extensive parts of both cerebral hemispheres. On the left, it involves the frontal lobe, which has abnormal sulcation, as well as a perisylvian region. On the right, it predominantly involves the perisylvian region, and is associated with schizencephaly extending to the abnormally shaped trigone of the lateral ventricle, and appearing of the 'close lipped' variety.
The septum pellucidum is absent, and the optic chiasm is small, particularly on the right, with a markedly atrophic right optic nerve.
The right thalamus and posterior parts of the caudate nucleus are also markedly reduced in volume, with ex-vacuo dilatation of the adjacent ventricle. As the fornices pass down towards the mammillary bodies, a region of grey matter intensity is demonstrated which is projecting into the roof of the 3rd ventricle and is not usually present, presumably representing further heterotopic abnormal grey matter.
The pituitary stalk is present and hypothalamus appears largely unremarkable. The posterior fossa is normal in appearance.