14-16 weeks gestational age 17-18 weeks gestational age 19-20 weeks gestational age 21-22 weeks gestational age 23-24 weeks gestational age 25-26 weeks gestational age 27-28 weeks gestational age 29-30 weeks gestational age 31-32 weeks gestational age 33-34 weeks gestational age 35-36 weeks gestational age 37-38 weeks gestational age Corpus callosum/septum pellucidum				Agenesis of the Corpus Callosum Agenesis of the Septi Pellucidi Anencephaly Arachnoid Cyst Arnold-Chiari Malformation Arteriovenous Malformation Cerebellar Hypoplasia Colpocephaly Dandy-Walker Variant/Malformation Encephalocele Hemorrhage Holoprosencephaly Hydrancephaly Megacisterna Magna Polymicrogyria Porencephaly Tuberous sclerosis Tumor Vein of Galen Malformation Venous Malformation Ventriculomegaly: Mild Ventriculomegaly: Moderate Ventriculomegaly: Severe