The Fetal Head and Brain - Penny
lissencephaly
"smooth brain" there are no sulci or gyri in the cerebral cortex
agenesis of the corpus callosum and CSP
"spoke wheel" pattern (sunburst sign)
corrected BPD
The OFD and BPD is shape corrected and equivalent to the HC, independent of the shape of the skull
porencephaly
a cyst communicated with the ventricular system, common after the fetus has experienced hemorrhage within one of both of the cerebral hemispheres
falx cerebri
a double fold of dura mater that is located within the inter hemispheric fissure which separates the cerebral hemispheres, echogenic linear formation coursing through the midline of the fetal brain
cerebellum
a dumbbell-shaped or figure eight-shaped structure noted in the posterior cranium of the fetus
proboscis
a false nose situated above the orbits, associated with holoprosencephaly
hydraencephaly
a fatal condition in which the entire cerebrum is replaced by a large sac of CSF, there is no cerebral cortex identified
Arnold-Chiari II Malformation
a group of cranial abnormalities associated with the NTD spina bifida.
brachiocephalic head
a head that is considered round or short and wide
cephalic index
a tool used for indicating the shape of the fetal head =BPD/OFD x 100 <75 denoted a dolichocephalic head >85 denoted a brachiocephalic head
cisterna magna
an anechoic fluid filled space posterior to the cerebellum , between the cerebellar vermis and the interior surface of the occipital bone
dolichocephalic head (scaphocephaly)
an elongated, narrow head shape
cave septum pellucidum
anechoic box shaped structure in the axial scan plane, does not communicate with the ventricular system and its absence is associated with multiple cerebral malformations including genesis of the corpus callosum
trisomy 18 ( edwards syndrome)
choroid plexus cysts often regress, although there is a slight association with:
Thanatophoric dysplasia
cloverleaf-skull
the ventricular system
composed of four ventricles who's purpose to to provide cushioning for the brain
corpus callosum
connects the cerebral hemispheres and allows communication between the two lobes, echogenic band of tissue within the midline of the brain.
thalamus
consist of two lobes located on either side of the third ventricle
Apert syndrome
craniosynostosis, midline facial hypoplasia, and syndactyly
arachnoid cysts
cysts that do not communicate with the ventricular system
hydrocephalus
dilatation of the ventricular system caused by increased volume of CSF
MSAFP
elevated ___ is associated with anencephaly
Dandy- Walker malformation
enlarged cisterna magna >10mm, the cerebellar vermis is absent and the 4th ventricle is enlarged
ventriculomegaly
enlargement of the lateral ventricle beyond 10mm
schizencephaly
fluid filled clefts within the cerebrum agenesis od che CSP and corpus callosum (50% of the time) ventriculomegaly
lateral ventricles
house the choroid plexus
AFP
lab value found in association with neural tube defects by exiting the fetus through the opening in the neural tube and allowing for a greater amount to pass into the maternal circulation
spina bifida
may result in a mass that protrudes from the spine meningocele- herniation of the meninges myelomeningocele - herniation of meninges and spinal cord
Arnold-Chiari II malformation
measurement of the cisterna magna less than 2mm is consistent with
mega cisterna magna and Dandy-Walker complex
measurement of the cisterna magna more than 10mm is consistent with
choroid plexus
mostly located within the atria of the lateral ventricles, is responsible for producing CSF
mesocephalic
normal to medium sized skull
occipitofrontal diameter
obtained at the same level as the BPD and HC, one caliper id placed in the anterior midline in the middle of the frontal bone and the other is placed in the middle of the occipital bone
biparietal diameter
obtained in the avail plane at the level of the CSP, thalmus, and falx, This is the same level as the third ventricle, which may be seen between the two lobes of the thalmus
cyclopia
orbits are fused and contain a single eye, associated with holoprosencephaly
craniosynostosis
premature fusion of the sutures: flexible structures that connect the cranial bones which remain slightly mobile until delivery to facilitate the passage of the skull through the birth canal
Trisomy 13 (patau syndrome)
present in 50-70% of fetuses diagnosed with holoprosencephaly
cephaloceles
protrusions of intracranial contents through a defect in the skull, the most common location is in the occipital region, possible elevation of MSAFP
Lemon sign - lemon shaped head Banana sign - banana shaped cerebellum obliterated cisterna magna
signs associated with Arnold-Chiari II Malformation
colpocephaly
small frontal horns and enlarged occipital horns (teardrop shaped lateral ventricles) associated with ageneiss of the corpus callosum and CSP, and arnold-chiari II
fontanelles or "soft spots"
spaces that exist between the forming fetal bones that are used as sonographic windows during neurosonographic exams on newborns
trisomy 18 (edwards syndrome)
strawberry shaped skull
head circumference
taken at the same time and same level of the cranium as the BPD, a measurement around the entire cranium
between the two lobes of the thalmus
the 3rd ventricle is located:
anterior to the cerebellar vermis
the 4th ventricle is located:
acrania
the absence of the cranial vault above the bony orbits
metopic suture
the fetal suture located within the frontal bone along the midline of the forehead
third ventricle
the inter thalamic adhesion (mass intermedia) passes through the
cerebrum
the largest part of the brain
HC
the most accurate measurement for estimating gestional age is
aqueductal stenosis
the most common cause of hydrocephalus in utero
teratoma
the most common intracranial tumor found in utero is the
alobar holoprosencephaly
the most severe form, often resulting in neonatal death, the cortex can take on three shapes resembling a "pancake", "cup", or "ball" there will be evidence of a horseshoe-shaped monoventricle, and the lobes of the thalmus may be fused and echogenic in appearance
10mm
the normal lateral ventricle does not measure more than _____ a the level of the atrium
foramen magnum
the opening at the base of the cranium through which the spinal cord travels
ventriculomegaly
the sonographic finding of the "dangling choroid" sign describes and echogenic choroid plexus, hanging limp, and surrounded by CSF, this finding is exceedingly specific for:
calcifications around the ventricles and ventriculomegaly
the sonographic intracranial findings consistent with intrauterine infections are___
aqueduct of Sylvius or the cerebral aqueduct
the third ventricle connects to the fourth ventricle inferiorly by means of a long, tubelike structure called:
cerebrum and cerebellum
the two main parts of the brain
exencephaly
type of acrania when a normal amount of cerebral tissue is present
anencephaly
type of acrania when there is no cerebral hemispheres present
holoprosencephaly
what cerebral abnormality are atypical facial features most commonly associated with
the resistance pattern of the MCA should be greater than that of the umbilical artery
when fetal shunting is suspected the sonographer should look at the ___
communicating hydrocephalus
when the obstruction causing excess CSF lies outside of the ventricular system
noncommunicating hydrocephalus
when the obstruction causing excess CSF lies within the ventricular system
fourth ventricle
with what structure does the posterior fossa cyst associated with DWM communicate