fetal face abnormalities (week four)

the width of the nasal bridge between ___ ____ is approximately the same as the size of each orbit- dividing the face into thirds

each orbit

hypotelorism:

orbits are spaced closer together than normal

usually associated with HOLOPROSENCEPHALY), trisomy 13, microcephaly anomaly, microcephaly, Williams syndrome

how will you measure hypotelorism

measure inter orbital distance, compare measurement to inter orbital distance chart.

transracial scan plane slightly lower than plane used for BPD

associations with hypertelorism

anterior cephaloceles

craniosynostosis

median cleft syndrome

Noonan syndrome

associations with teratogen exposure with hypertelorism include

phenytoin

valproate

dilantin

anophthalmia results from

failure of the optic vesicle to form

demonstrates absence of the globe and often the orbit on the axial view through the expected level of the orbits

unilateral and ophthalmia is associated with

goldenhar-gorlin syndrome

how is the nose lips image obtained

by moving the scanner forward from the coronal orbit view to the very front of the face

image demonstrates two nostrils and a upper lip

being able to visualize the nose, upper lip, lower lip, and chin in the same coronal image makes ____ an unlikely finding

micrognathia

how to get the palate image

trv image used to obtain a cross section through the upper lip and hard palate, demonstrates the skin line is intact of the upper lip

the width of the mandible should be similar to the width of the ___and may be reduced in micrognathia

maxilla

trv image obtaining a cross section through the lower lip and jaw for the

mandible

most common facial abnormality

cleft lip and palate

why does a cleft lip and palate usually occur

due to failed fusion of the maxilla, primary and secondary palates

2/3 of pts affected with cleft lip will also have cleft palate

two major groups of cleft lip and palate

1- upper lip and anterior maxilla with or without involvement of soft and or hard palate

2- cleft results from lack of fusion of the maxillary prominence with the nasal prominence on one or both sides

cleft involving hard and soft palate without cleft lip results from

failure of maxilla, primary, secondary palates diffuse

associations with cleft lip and palate would be

trisomy 13

CNS anomalies

cardiac anomalies

teratogens

holoprosencephaly

amnionic band syndrome

what will be present with the fetus if they have cleft lip or palate

polyhydraminos and small stomach

hypoplastic mandible is also known as

small chin

associations with micrognathia

trisomy 18

pierre robin sequence

hemifacial microsomia

goldenhard-gorlin syndrome

sonographic evaluation for micrognathia includes

sag view of facial profile

protrusion of upper lip

small chin

macroglossia:

persistant protrusion of the tongue

associations include-

beck with-weidemann syndrome

congenital hypothyroidism

for macroglossia tongue protrudes beyond

alveolar process

cyclopia-

midline fusion of orbits

if nasal tissue is present it is represented by blind proboscis (protrusion of nasal tissue above the orbit)

associations of cyclopia:

holoprosencephaly

teratogen exposure

cytomegalovirus

sonographic eval of cyclopia:

trx view

interorbital distance

hypotelorism

fetal profile( demonstrates proboscis)

clinical associations of cyclopia-

elevated maternal serum alpha-fetoprotein

greater than 2.5 multiples of the median is abnormal and suggests and open neural tube defect

fetal alpha fetoprotein is normally found circulation in maternal blood

membranous covering over and open neural tube defect allows excess AFP to enter maternal circulation

increased fundal height

anencephaly

lemon shape abnormality-

associated with spina bifida

bilateral indentation of the frontal bones

strawberry head shape-

associated with trisomy 18

flattened occiput and narrowing of the frontal part of the head

cephalic index for brachy and dolichocephaly

brachy- greater than 85%

dolicho- less than 70%

The brachycephalic fetal head has a shortened ____ ____ distance and a larger ___.

occipital-frontal, BPD

ventriculomegaly is caused by what disorders

obstruction to outlfow

decreased CSF absorption

overproduction of CSF

what’s hydrocephalus

term for ventricular enlargement secondary to increased intracranial pressure and/or head enlargement

measurement of the atrium of the lateral ventricles should not exceed

10mm

slide 38

primary failure of brain growth is from

ventriculomegaly

overproduction of CSF results in

choroid plexus papilloma

chiari 2 malformation is associated with

spina bifida

ventriculomegaly may be seen as normal variant later in 2nd tri for

male fetuses and fetuses large for GA

associations of ventriculomegaly

spina bifida

dandy-walker malformation

encephalocele

renal malformations

renal malformations

abnormal karyotypes

sonographic appearance of ventriculomegaly

-presence of excess fluid in lateral and third ventricles

-atrium of lateral ventricles measuring greater than 10mm

-choroid plexus may dangle within the CSF

associated sonographic findings of ventriculomegaly include

polyhydraminos

abnormal fetal lie

hepatomegaly and fetal ascites with associated infection

meningomyelocele

acrania

skull is absent but brain is present

brain is usually abnormal and shows signs of atrophy

acrania has elevated…

AFP, can be diagnosed as early as 12 wks GA, cranium ossifies around 11 wks

anencephaly-

absence of skull and cerebral hemispheres

some features that come with anencephaly

bulging eyes

macroglossia

short neck

AFP will be elevated

____ brain tissue may be evident with anencephaly

rudimentary

are orbits and face usually present with anencephaly

yes “frog like”

anencephaly is often associated with

polyhydraminos, talipes is a common finding

can be diagnosed as early as 12 wks

what portions MAY BE present with anencephaly

midbrain and brain stem

what’s encephalocele

bony defect in the skull allows herniation of intracranial contents

contents include brain tissue and CSF

(may be caused amniotic bands)

can be associated with mocked-gruber syndrome

different classifications of encephalocele

occipital- most common

frontal-

parietal-

sonographic view of encephalocele

mass extending from calvarium, may be cystic near the cranium, brain tissue may be present within mass, cranial defect will be present

holohprosencephaly:

incomplete cleavage or diverticulation of primitive forebrain into 2 hemispheres

associated with trisomy 13

classifications of holoprosencephaly

alobar

semilobar

lobar

lobar and semi lobar typically lethal in first year of life; lobar to have normal lifespan but severe development delay and visual impairment

alobar holoprosencephaly:

most severe form lacking 2 hemispheres

large single ventricle with minimal amount of surrounding cerebral tissue

what’s absent with alobar

fall, corpus collusum, cave septum pellucidum

facial abnormalities with alobar

hypotelorism, cyclopia, midline facial clefts

semi lobar:

occipital and temporal horns may be present with rudimentary 3rd ventricle

variable development of fall and inter hemisphere fissure

associated with cleft lip and palate

lobar:

least severe form, 2 hemispheres are present, absence of cave septum pelluicidum and corpus collusum

50 % have ____ ____ particularly ____ with holoprosencephaly

chromosomal abnormalities, trisomy 13

sonographic appearance of holoprosencephaly

Fetal cranium appears to have large, midline cystic spaces with varying degrees of peripheral cerebral tissu

vermis is developed when

18 wks

Dany-walker malformation-

dysgenesis of cerebellar vermis

large 4th ventricle which communicates with a posterior fossa fluid collection

cisterna magna enlargment

vermian hypoplasia:

abnormal vermin development, midline of cerebellum (can’t diagnose until have 18 wks)

associated abnormalities with dandy walker complex

CNS 50-70% of the time

ventriculomegaly

agenesis of corpus callosum

spina bifida

microcephaly

vermian agenesis is associated with

abnormalities similar to those found with DWM, may be functionally normal after birth

sonographic appearance of the DWM

Complete or partial agenesis of the cerebellar vermis will create a splaying

of the cerebellar hemisphere

Arnold Chiari type 2 malformation:

displacement of cerebellar vermis, 4th ventricle and medulla oblogata through foramen magnum into the upper cervical Canal

caused by traction on the hindbrain

sonographic appearance of Arnold chiari type 2 malformation

cerebellum will be compressed against the back of the cranium and conform into c-shape (banana sign)

cisterna magna will be obliterated

ventriculomegaly

frontal bones will indent or scallop to create a lemon shape to the cranium

microcephaly (small head measuring more than 3 standard deviations below normal) associations:

intrauterine infection

aneuploidy/ syndromes

underlying CNS anomaly

sonographic appearance of microcephaly:

• Small BPD

• Decreased HC/AC ratio

• Poor cranial growth on serial

scans

• Abnormal intracranial

architecture

• High false positive rate

the ___ ___ is the largest connecting neural tract connecting the cerebral hemispheres

corpus callosum

absence of corpus callosum allows ventricles to…

ride up and become displaced and misshapen

agenesis of corpus callosum is commonly associated with

trisomy 18 and 13

holoprosencephaly

medican facial clefts

DWM

clinical associations of agenesis of the corpus callosum

low intelligence

seizures

sonographic appearance of agenesis of corpus callosum

• Disproportionate enlargement of occipital horns

• Lateral displacement of both medial and lateral ventricular walls

• Widely separated lateral ventricular frontal horns

• Pointed anterior ends of lateral ventricles

• Ventricles may be teardrop shaped

• Absence of cavum septum pellucidum

• Elevation and dilatation of the 3rd ventricle

what’s vein of Galen aneurysm:

Cerebral arteriovenous malformation which drains into the vein of Galen (rare)

The vein of Galen becomes dilated due to

increased from from the malformation

sonographic assessment of vein of Galen aneurysm

• Dilated veins are seen as a single fluid space close to midline

• Shape may be irregular

• Confirmed by Doppler

• Turbulence associated with AV malformation

hydranencephaly:

most severe degree of porencephaly or brain destruction

Destructive process causing total or near total absence of cerebrum

degeneration of the cortex with fluid replacement

etiology of hydranencephaly:

occlusion of the carotid arteries in the first or early second trimester (most common)

may result from infection

sonographic appearance of hydranencephaly:

head size usually normal but can be big or small

fall can be displaced or hypoplastic

variable presence of third ventricle

large anechoic area in the cranial vault surrounding midbrain and basal ganglia

may be difficult to distinguish from a severe hydrocephaly

schizencephaly:

a destructive process that creates a cleft in the cerebral cortex

fluid filled clefts in the cerebral cortex may be unilateral or bilateral

associations of schizencephaly:

midline brain defects

ventriculomegaly

septic optic dysplasia

agenesis of corpus callosum/ septum pellucidum

heterotopias (displacement of gray matter)

polymicrogyria (many folds on the surface of the brain)

lissencephaly:

brain surface is smooth without normal sulci or gyri

difficult to diagnose until 3rd tri

possibly see ventriculomegaly

associations with lissencephaly:

agenesis of the corpus callosum

DWM

colpocephaly

porencephalic cysts

cysts filled with CSF that communicate with the ventricular system

sonographic assessment of porencephalic cysts

cyst in the brain parenchyma

cyst communicates with ventricular system or subarachnoid space