Fetal Head/face/neck Flashcards
Anencephaly
No Brain,skull
Frog like face appearance
MOST COMMON NTD
Acrania (aka. Exencephaly)
No skull bones with presents of brain
Cephalocele
Protrusion of the meninges and/or brain through a defect in the cranium.
Most most often seen in the occipital region (80%)
Meningocele
Protrusion of the meninges (cystic looking)
Cephalocele
Encephalocele
Protrusion of brain tissue - complex structure
Cephalocele
Meningoencephalocele
Meninges and brain tissue - complex
Cephalocele
Meningoencephalocele
Protrusion of Meninges, brain tissue and ventricle - Complex
Cephalocele
Iniencephaly
Defect in the occiput, usually involves the foramen magnum.
-Retroflexion of the fetal head STAR GAZER
Spina Bifida>
- Meningocele
- Meningomyelocele
- Open V.s. Close
Failure of the two halves of the vertebral arch to fuse. *73% lumbosacral region)
- Meningocele = Herniation of meninges (cystic on US)
- Meningomyelocele = meninges and spinal cord (complex cystic mass on US)
- Open = open wound
- Closed = Closed wound
Spina bifida on US
In transverse = splaying of the posterior ossification centers with V or a U configuration
In sag= “train track” will come to a stop
Cranial findings associated with spina bifida
~Lemon sign – anterior calvarium collapse (frontal)
~Banana sign – obliteration of the cisterna magna by cerebellum
~Ventriculomegaly- block of spinal fluid flow
Arnold-Chiari Malformation
Defects in the cerebellum and brainstem. A part of the cerebellum is located below the foramen magnum (normally located above the foramen magnum).
Arnold-Chiari Malformations Type 2
Associated with spina bifida, characterized by displacement of the cerebellum, brain stem, fourth ventricle, pons and medulla oblongata through the foramen magnum.
This is usually associated with hydrocephalus and meningomyelocele. (Cerebellum = banana (loss of dumbbell shape) Lemon (head resemble lemon), ventriculomegaly is seen.
Associated with Arnold-Chiari 2
Spina Bifida 80-90%
Trisomy 18
Dandy-walker
- Agenesis of cerebellar vermis( Large midline cystic structure in posterior fossa).
Dandy-Walker malformation
- *MOST SEVERE**
- Complete/partial agenesis of cerebeller vermis
- Dilation of fourth ventricle
Dandy-Walker variant
Partial agenesis of cerebellar vermis
Normal forth ventricle
Key hole
Posterior Fossa Arachnoid Cyst
- Collection of CSF enclosed within the layers of the arachnoid that can displace adjacent normal brain parenchyma.
- *Does not communicate with ventricles or subarachnoid spaces**
Holoprosencephaly
BRAIN & FACE
Trisomy 13
ALOBAR - most severe
Several abnormalities of the brain and face resulting from incomplete cleavage (division) of the primitive prosencephalon portion of the brain (forebrain)
Agenesis of the Corpus callosum
> DX before 20 wk may be difficult
> Sonographic appearance:
- Teardrop- shaped ventricle - Absent cavum septi pellucidi - Sunburst appearance of gyri and sulci
Aqueductal Stenosis
> Obstruction, atresia, or stenosis of the aqueduct of sylvius causing ventriculomegaly.
> Sonographic appearance
Enlargement of the lateran ventricles and third ventricle in the presence of a normal forth ventricle.
Vein of Galen Aneurysm- (AKA- A vein of Galen malformation)
> Rare AVM
• Cystic space that may appear irregular in shape and is located midline and posteriorsupesior to the third ventricle.
• Turbulent flow with color doppler evaluation
Choroid plexus cyst
> Should resolve between 22-26 wks
Benign if no other anomalies found
Associated with Trisomy 18
Porencephaly- (AKA Porencephalic cysts)
> Single of multiple cystic masses in the brain
> Communicate with the ventricular system of the subarachnoid space
Hydranencephaly
> Water, No brain
> Destruction of the Cerebral hemispheres replaced with CSF by the occlusion of the internal carotid arteries.
Schizencephaly
> Rare malformation by abnormal clefts in the cerebral hemispheres
Splits brain into anterior and posterior parts
Lissencephaly
> The surface lacks the normal sulci and gyri, and appears smooth.
DX can not be made until the 3rd trimester
Ventriculomegaly –&– Hydrocephalus
Ventriculomegaly - Increase in CSF in ventricles, Lateral ventricle >10mm, Main cause aqueductal stenosis
Hydrocephalus - ^ with enlargement of fetal head
Microcephaly
Small head circumference, 3 standard deviations below normal.
Skull shapes;
- Clover-leaf
- Lemon-shaped
- Strawberry-shaped
- Clover-leaf - Dwarfism
- Lemon-shaped - Seen often with banana shaped cerebellum due to open NTD, Arnold-Chiari 2, spina bifida
- Strawberry-shaped - Trisomy 18
Frontonasal Dysplasia
Facial defect affecting midline of face.
-Midline cleft lip/palate-
Cleft Lips/Palates
- Most common
- US appearance of Cleft Lip/Palate
• Large gap in upper lip seen on coronal view of lip and nose
• Mass effect formed by the upper lip bulging forward
• Nose is usually flattened & widened
Midline cleft lip/palate
-Frontonasal Dysplasia
The face predicts the brain
Search for coexisting brain anomalies
Profile:
- Absent/flattened nasal bone –
- Forehead/Frontal bone -
- Enlarged tongue –
- Chin – Microgenathia (undersized jaw)
- Epignathus. –
- Absent/flattened nasal bone – Trisomy 21
- Forehead/Frontal bone - slopping or bossing
- Enlarged tongue – Macroglassia, Beckwith-Wiedemann syndrome
- Chin – Microgenathia (undersized jaw). – chromosomal anomalies
- Epignathus. – a teratoma arising from the oral/nasal cavity of pharynx
Orbits:
- Anopthalmis –
- Micropthalmia –
- Hypotelorism –
- Hypertelorism. –
*Dacryocystocele –
- Anopthalmis – Absent eye of eyes
- Micropthalmia – Small eyes
- Hypotelorism –decrease distance between eyes
- Hypertelorism. – increased distance between eyes
*Dacryocystocele – Protrusion of the lacrimal sac
Neck:
- Nuchal Translucency
- Nuchal fold
- Cystic hygroma
- Fetal thyroid goiter
- Nuchal Translucency - Abnormal >3mm, measured between 11-14wks
- Nuchal fold - Abnormal >6mm, measured between 15-21wks, Associated with Trisomy 21
- Cystic hygroma- Lymphatic obstruction, Cystic, single/multiloculated fluid filled cavity, Posterior &/or lateral aspect of fetal neck, associated with Trisomy 21, Turners’s
- Fetal thyroid goiter - Solid appearing mass, anteriorly located
