Antenatal diagnosis of aneurysmal malformation of the vein of Galen.

Vein of Galen malformation (VGAM) results from an aneurysmal aberration with an arteriovenous shunting of blood. Vein of Galen aneurysmal malformations are the most frequent arteriovenous malformations in infants and fetuses. The congenital malformation develops during weeks 6-11 of fetal development.