Fetal Nervous system Flashcards
where is CSF formed
lateral ventricles
what opening is between the lateral ventricle and the third ventricle
foramen of monroe
when do you see an increase of AFP and polyhydraminos
nuero tube defects
parts of the cephalon rostral neuopore
- prosencephalan (forebrain)
- mesencephalon (mid)
- rhombencephalon (hind)
when does the rostral tube end close
25 days after conception
what is the csp medial to
the frontal horns
What trisomy is a choroid plexus cyst associated with and when is it seen
asso. w/ trisomy 18
seen between 15-26 weeks
choroid plexus cyst sono appearance
size .3. to 2 cm
may cause compression
2 causes for ventricular megaly
- non communicating obstruction: obsruction in ventricles
- communicating obstruction: CSF gets absorbed in subarachnoid spaces
Aqueductal stenosis
most common cause for ventricularmegaly
enlarged 3rd ventricle
normal 4th
what is Dandy walker syndrome
rare
abnormal development of cerebellum w/ maldevelopment of 4th vent
Dandy walker syndrome associated and linked with
linked w/ rubella, cmv, etoh
assoc. w/ diabetes
or unknown
Dandy walker syndrome sono findings
post. fossa cyst
splaying of cerebellar hemisphere
ventriculomegaly 80%
differential diagnosis for Dandy walker syndrome
arachnoid cyst
Arachnoid cyst etiology
inflammatory changes
Arachnoid cyst sono
flattening of cerebral vermis
no communication between cyst & 4th ventricle
3 types of holoprosencephaly
- alobar
- semilobar
- lobar
Hydrancephaly etiology
most common is bilateral occlusion carotid arteries and jugular veins
Hydrancephaly sono findings
brain stem bulges inside anechoic head
brain matter replaced with CSF
poly
Porencephaly etiology
intracranial hemorrhage or infarction
necrosis
traumatic event to fetus like car accident
Porencephaly sono appearance
cystic areas
varied due to hemorrhage
when is the corpus callosum fully developed
by 12 to 18 weeks
agenesis of corpus callosum sono appearance
dilatation of 3rd ventricle
lateral ventricles pushed more lateral and superior
occipital horn dilation
**ABSENT CSP **
what opening is between the 3rd and 4th ventricle
aqueduct of sylvius
what openings is between the 4th ventricle and the subarachnoid space
foramen of luschka and foramen of magendie
how much should microcephaly measure to be diagnosed
2-3 standard devaitions below the mean
if you see holoprosencephaly where else should you look for defects?
midline defects
facial defects
what will be elevated in maternal blood work for open nueral defects?
alfa feto protein or AFP
what is the location of a vein of galen aneurysm
post. and slightly superior thalami
when do you see a gale anuerysm
3rd tri
differential diagnosis for vein of gale anuerysm
arachnoid cyst
agensis of corp. callosum
what is the most common nueral tube defect
anecephalic
when should the nueral tube close
23-26 days after conception
what can you see on sono for anecephalic
polyhdramnios
absence of brain
frog like appearance
what anomalies are associtaed with anecephaly
-Cardiovascular
-GI
omphalocele
poly
diaphragmatic hernia
cleft lip
spina bifida
what is the most common location for a cephalocele
occipital region
what trisomys are associated with cephalocele
trisomy 13 and 21
what findings are associated with cephalocele
hydrocephalus or ventricularmegaly
spina abifida
microcephaly
Meckel gruber syndrome
CV anomalies
encephalocele Differential diagnosis
cystic hygroma
teratoma
hemangioma
scalp edema
microcephaly etiology
exposure radiation
brain abnormalities
when is microcephaly diagnosed
2nd and 3rd tri
What is hydraencephaly
Absence or near absence of brain tissue
What is
A vein of Galen aneurysm
Direct communication of a vein and middle cerebral artery
