Ch 59 Fetal Neural Axis

Question 1

Remnant brain with anencephaly is covered by a thick membrane called

Answer 1

Angiomatous stroma or cerebrovasculosa

Question 2

_____ usually progresses to anencephaly as the brain slowly degenerates as a result of exposure to amniotic fluid

Answer 2

Acrania {may be a precursor to anencephaly}

Question 3

Causes of anencephaly include

Answer 3

1. Meckel - Gruber
2. Chromosomal anomaly
3. Increased risk with diabetes mellitus
4. Enviromental & dietary factors
5. Amniotic band syndrome

Question 4

Neural tube defect in which the meninges alone or the meninges and brain herniated through a defect in the calvarium

Answer 4

Cephalocele

Question 5

Herniation of meninges and brain through a calvarium defect

Answer 5

Encephalocele

Question 6

Herniation of meninges ONLY

{has a 60% chance of normal mentation}

Answer 6

Cranial meningocele

Question 7

What is the most common open neural tube defect?

Answer 7

Anencephaly

Question 8

Complete/ partial absence of the forebrain; With the presence of the brain stem, midbrain, skull base, and facial structures. {Frog like appearance}

Answer 8

Anencephaly

Question 9

Autosomal-recessive disorder characterized by encephalocele, polydactyly, polycystic kidneys

Answer 9

Meckel-Gruber Syndrome

Question 10

Lack of closure of the vertebral column {a cleft or opening in the spine}

Answer 10

Spina Bifida

Question 11

Spina bifida most commonly occurs in the ______ and ______ regions of the spine

Answer 11

Lumbar & Sacral

Question 12

Open neural tube defect WITHOUT external abnormalities

{normal spinal cord, nerves, & normal neurologic developemnt} {spinal defect covered by skin or hair}

Answer 12

Spina bifida occulta

Question 13

Open neural tube defect WITH external abnormalities and neurological complications

Answer 13

Spina bifida cystic or aperta

Question 14

Most severe form of spina bifida

Answer 14

Spina bifida cystic or aperta

Question 15

Only meninges through a defect

Answer 15

Meningocele

Question 16

Meninges and neural elements through a defect

Answer 16

Meningomyelocele

Question 17

Increased AFP with spina bifida {T/F}

Answer 17

TRUE

Question 18

A congenital anomaly associated with spina bifida CYSTICA in which the cerebellum and brain stem are pulled down through the 4th ventricle, cisterns magna, and foramen magna into the cervical spinal cord; the cerebellum distorts to a “banana sign”

Answer 18

Arnold-Chiari Malformation

Question 19

Most common form of Arnold-chiari malformation {this is the type seen in OB ultrasound}

Answer 19

Type II

Question 20

Banana sign is associated with dilated ______ and______, and meningomyelocele

Answer 20

3rd & lateral ventricles & meningomyelocele

Question 21

The banana shaped cerebellum is create by an obliterated _________

Answer 21

Cisterna magna

Question 22

Lemon sign is associated with ______ and ______

Answer 22

Encephalocele & thanatophoric dysplasia

Question 23

Abnormal development of the roof of the 4th ventricle which causes obstruction of the 4th ventricle outflow & cystic enlargement of the posterior fossa

Answer 23

Dandy walker malformation

Question 24

Differential diagnosis of dandy walker malformation

Answer 24

arachnoid cyst

Question 25

Sonographic appearance of _______ : * large midline cystic structure in posterior fossa {dilated 4th ventricle} * cerebral hemisphere might be splayed and flattened due to complete or partial absence of the vermis * enlarged cisterna magna * ventriculomegaly * polyhydramnios

Answer 25

Dandy walker malformation

Question 26

Most severe form of holoprosencephaly

Answer 26

Lobar holoprosencephaly

Question 27

________- SMALL BRAIN * single venticle * incompletely fused thalami * no midline brain structures

Answer 27

Semi lobar holoprosencephaly

Question 28

mildest form of holoprosecephaly {rarely detected on ultrasound}

Answer 28

Lobar holoprosencephaly

Question 29

Hypotelorism with flattened nose and a single nostril

Answer 29

Cebocephaly

Question 30

Severe hypotelorism with proboscis

Answer 30

Ethmocephaly

Question 31

Sonographic findings: * C-shaped single ventricle * Horseshoe shape brain tissue * Fused thalami * Absent falx, cavum septum pellucidum, corpus septum pellucidum, corpus callosum, optic tracts,olfactory bulb, & 3rd ventricle

Answer 31

Sonographic findings for holoprosencephaly

Question 32

Broad transverse nerve track connecting the 2 cerebral hemispheres; thought to involve vascular disruption or inflammatory lesion before 12 weeks {sporadic condition}

Answer 32

agenesis of the corpus callousum

Question 33

Sonographic findings: * Absent cave septi pellucidum & corpus callosum * Elevation and dilation of the 3rd ventricle * Lateral ventricle displaced upward & outward * dilated occipital horns {colpocephaly} * ^ gives lateral ventricle a tear drop shape

Answer 33

agenesis of the corpus callousum

Question 34

Results from stenosis, atresia, or obstruction of the aqueduct of sylvius which causes ventriculomegaly

Answer 34

Aqueduct stenosis

Question 35

The aqueduct of sylvius connects the .....

Answer 35

3rd & 4th ventricles

Question 36

Aqueduct stenosis may result from intrauterine infections such as.... {3}

Answer 36

1. Cystomeglovirus 2. Rubella 3. Toxoplasmosis

Question 37

Primary aqueduct stenosis is usually ___-linked

Answer 37

X-linked

Question 38

Rare event demonstrating an enlarged vein communicating with a normal appearing artery {AV malformation}

Answer 38

Vein of Galen malformation

Question 39

Vein of galen aneurysm {malformation} is usually isolated but has been associated with... {3}

Answer 39

1. congenital hear defects 2. cystic hygromas 3. hydrops

Question 40

Sonographic findings: * Irregular shaped cystic space located midline and poster-superior to the 3rd ventricle * turbulent flow with doppler evaluation

Answer 40

Vein of galen aneurysm

Question 41

Represents the most common intracranial "abnormality" reported prenatally

Answer 41

Choroid plexus cyst

Question 42

Choroid plexus cyst usually resolve by...

Answer 42

22-16 weeks

Question 43

Choroid plexus cysts contain ____ and ____

Answer 43

cerebral spinal fluid & cellular debris

Question 44

Large choroid plexus cysts { >1 cm} carry greater risk for an underlying chromosomal anomaly, especially ______

Answer 44

Trisomy 18 - edwards

Question 45

RARE disorder characterized by clefts in the cerebral cortex

Answer 45

Schinzencephaly

Question 46

This disorder is associated with congenital infections, drugs, and other toxic exposures, vascular accidents, and metabolic abnormalities

Answer 46

Schinzencephaly

Question 47

Sonographic appearance: * fluid-filled cleft in cerebral cortex extending from ventricle to calvarium * ventriculomegaly

Answer 47

Schinzencephaly

Question 48

What is the destruction of cerebral hemispheres by bilateral occlusion of the internal carotid arteries; the cerebral hemispheres are replaced by cerebral spinal fluid

Answer 48

Hydranencephaly

Question 49

Sonographic findings: * CSF, no normal brain tissue * absent or partially absent falx * presence of the midbrain, basal ganglia, & cerebellum * possible identification of the choroid plexus & possible macrocephaly

Answer 49

Hydranencephaly

Question 50

Ventriculomegaly is defined as lateral ventricular enlargement of ____

Answer 50

greater than 10 mm

Question 51

Ventriculomegaly in the neonate with enlargement of the head

Answer 51

Hydrocephalus

Question 52

is Anencephaly is more common in females or males? / Whites or blacks?

Answer 52

Females, Whites | {also more common in the UK}

Question 53

Filly's rules: If the atrium of the lateral ventricle and the cisterna magna BOTH measure ______, there is a 95% negative predictive value for any central nervous system anomaly

Answer 53

Equal to or greater than 10 mm