Vein of Galen malformations
Pure cisternal fistula between pericallosal arteries, posterior cerebral artery and the vein of Galen.
Fistulous connection between the thalamoperforators and the vein of Galen.
Mixed form with characteristics of both Type 1 and Type 2 lesions.
Plexiform AVM with one or more intrinsic niduses within the mesencephalon or thalamus with draining veins emptying into the vein of Galen.