What is Acrania?
presence of brain tissue with absence of skull bones, no froglike eyes, enhanced sulci marking
What is Holoprosencephaly?
a common large ventricle (monoventricle) with absence of the corpus callosum, cavum septum, and falx, has a fused thalamus
What is Anencephaly?
the most common neural tube defect, absence of the cerebral hemispheres and cerebellum, brain stem is present but no skull bones, froglike eyes, covered, AFP up
What is Encephalocele?
cranial meninges or meninges AND brain tissue protrude through a defect in the calvarium, must identify the occipital defect to rule out cystic hygroma
What is Choroid Plexus Cyst?
round or oval anechoic structure found in the choroid plexus, contains CSF, uni or bilateral, usually resolve ~ 22-26 weeks, can be linked to T18 & 21
What is Hydranencephaly?
fluid filled head replacing cerebral hemispheres, results from insult or bilateral occlusion of the fetal internal arteries
What is Dandy Walker Syndrome?
large 4th ventricle cyst seen in the posterior fossa replacing the cerebellum (results in an increased cisterna magna measurement)
What is Vein of Galen Aneurysm?
an arteriovenous malformation, involves an arterial communication with the vein of galen, leads to right sided heart overload
What is the third ventricle also referred to as?
The Aqueduct of Sylvius
What is ventriculomegaly?
Any enlargement of the ventricular system
What is Arnold Chiari malformation?
displacement of the 4th ventricle into the cervical canal (downward displacement of the cerebellum: results in a small cisterna magna measurement)
What is hydrocephalus?
ventriculomegaly WITH increased intraventricular pressure