Fetal Central Nervous System

Front 1

The neural tube will close

Back 1

6 menstral weeks

Front 2

Which is the best plane to detect Spina Bifada

Back 2

Transverse; location and configuration of ossification, musculature of back, integrity of skin line

Front 3

The sagittal plane of spine detects

Back 3

Cervical and lumbosacral curvatures, sacral caudal tapering, vertebral ossification centers.

Front 4

What structures are documented at axial sections of brain

Back 4

Cavum Septum Pellucidum, thalami, lateral ventricles, choroid plexus

Front 5

What measurements are taken at axial sections

Back 5

BPD, HC, atrium of lateral ventricle < 10mm normal

Front 6

In Oblique Axial section of brain what structures are seen?

Back 6

Cerebellum, Brain stem, Cisterna Magna (normal >3mm and < 10mm)

Front 7

Oblique Axial sections are obtained through what part of brain?

Back 7

Posterior Fossa

Front 8

Neural tube defects occur when neural tube fails to close by.

Back 8

6 weeks

Front 9

Neural Tube Defects allow

Back 9

Cerebrospinal Fluid to escape into amniotic fluid and maternal serum levels of AFP.

Front 10

Elevated levels of maternal AFP

Back 10

Require a targeted sonogram

Front 11

If sonogram fails to identify reason elevated MSAFP

Back 11

Recommend Amniocentesis

Front 12

Amniocentesis detects what in amniotic fluid

Back 12

Elevated Acetylcholinesterase in the presence of NTDs.

Front 13

Anencephaly

Back 13

Congenital absence of cerebral hemispheres and cranial vault

Front 14

What is the incidence of Anencephaly

Back 14

1 out of every 1000 births

Front 15

Anencephaly is more common

Back 15

In females and multiple gestations

Front 16

Anencephaly occurs with failure of neural tube to close by

Back 16

24 days gestation ( 38 menstral days)

Front 17

Anencephaly is characterized by

Back 17

Open defect covered by angiomatous stroma instead of skin an bone

Front 18

What structures of brain are present in Anencephaly?

Back 18

Brain stem and bony base of skull

Front 19

Anencephaly is associated with

Back 19

Polyhydraminos due to ineffective fetal swallowing. May also be associated with spina bifida

Front 20

Sonographic appearance of Anencephaly

Back 20

Identify fetal cranium by 12 weeks ( 15 weeks latest), Absence of cranial vault and cerebral hemispheres), face and orbits present, polyhydraminos (40-50% cases)

Front 21

Acrania

Back 21

Developmental abnormality where the cranium is partially or completely absent with development of abnormal brain tissue.

Front 22

Sonographic appearance Acrania

Back 22

Lack of echogenic cranium with large amount of brain tissue, transvaginally seen at 12 weeks (16 weeks transab)

Front 23

Encephalocele

Back 23

Herniation of brain and meninges OR meninges and CSF through a cranial defect.

Front 24

Prognosis of Encepholocele

Back 24

Depends on the amount of brain involved and associated findings.

Front 25

What fetal syndrome is an encepholocelee asssociated

Back 25

Meckel- Gruber syndrome

Front 26

Encepholocele location is

Back 26

Usually midline, MC occipital, may be frontal or lateral.

Front 27

If Encepholocele is asymmetric or atypical location consider

Back 27

Amniotic band syndrome

Front 28

Sonographic findings of Encepholocele

Back 28

Purely cystic extracranial mass ( meningocele), Solid mass contiguous with cranium (cepholocele)

Front 29

Encephocele is often associated

Back 29

Hydrocephalus and polyhydraminos

Front 30

Spina Bifada

Back 30

Lack of closure of vertebral column

Front 31

Prognosis is poorest in infants who present with

Back 31

Total paralysis below the region, kyphosis, hydrocephalus

Front 32

Sonographic frontal bone appearance of Arnold Chiari 2

Back 32

Lemon Sign- flattening of temporal/ frontal bones due to decreased inttracranial pressure.

Front 33

So no graphic appearance of posterior region in Arnold Chiari 2

Back 33

Banana Sign- obliteration of Cisterns Magna by abnormal configuration of cerebellum.

Front 34

Iniencephaly

Back 34

Rare malformation where the occiput is fused to the cervucal region. Cervical spina bifada and occipital encephalocele are present.

Front 35

Sonographic findings of Iniencephaly

Back 35

Marked head and neck hyperextension, occipital encephalocele/cervical spina bifida.

Front 36

Ventricle omega my/Hydrocephalus

Back 36

Dilation of ventricular system 2ndary to an increase in an increase in volume of CSF.

Front 37

Effects of hydrocephalus

Back 37

Flattening of parenchyma and spread of CSF which causes brain damage

Front 38

What ate the classifications of Hydrocephalus

Back 38

Obstructive/None communicating, Communicating, Idiopathic.

Front 39

How is Obstructive/ Non communicating hydrocephalus caused

Back 39

Obstruction of CSF flow d/t aqueductal stenosis

Front 40

Describe the flow if the CSF through the ventricles.

Back 40

Lateral ventricle----- interventricular foramen/ foramen of Moro---Third ventricle- ----Cerebral Aqueduct/ Aqueduct of Sylvius-------4th ventricle

Front 41

Ventriculomegaly/ hydrocephalus

Back 41

Dilatation of ventricular system secondary to an increase in the volume of cerebrospinal fluid (CSF).

Front 42

Effects of hydrocephalus incluxe

Back 42

Flattening of parenchyma and spread of CSF, which causes brain damage.

Front 43

What are the classifications of hydrocephalus

Back 43

Obstructive or Non communicating, Communicating, Idiopathic.

Front 44

Obstructive/Non-communicating causes

Back 44

Caused by obstruction of CSF flow due to aqueductal stenosis ( narrow Aqueduct of Sylvius due to inflammation or developmental process), CNS anomaly ( spina Bifada, Dandy Walker malformation), tumor.

Front 45

Communicating Hydrocephalus

Back 45

Dilation of ventricles caused by obstruction of CSF flow outside of ventricular system. Caused by faulty absorption or increased CSF production.

Front 46

Sonographic appearance of hydrocephalus

Back 46

Presence of excess fluid in lateral ventricles, >1cm, dangling choroid plexus,

Front 47

Associated sonographic findings of hydrocephalus

Back 47

Polyhydraminos, abnormal fetal lie, hepatomegaly and fetal ascites with associated infection, meningomyocele me Dandy Walker formation, intracranial tumor.

Front 48

Transverse Sonographic findings of Spina Bifada

Back 48

Splaying of posterior elements into U or V configuration. Cystic structure extending from the back when sac is intact. Appears small, simple cystic or a cyst with septations and or solid matter.

Front 49

Sagittal appearance of Spina Bifada

Back 49

Splaying of parallel ossification centers. Soft tissue defect or discontinuity of skin and muscle of posterior back.

Front 50

Associated Intracranial findings of Spina Bifada

Back 50

Secondary to Arnold Chiari 2

Front 51

Holoprosencephaly

Back 51

Spectrum of disorders resulting from absent or incomplete division of the forebrain into cerebral hemispheres and lateral ventricles.

Front 52

What is holoprosencephaly associated with

Back 52

Facial anomalies ( the face predicts the brain). Range from cyclopia (single orbit) with a proboscis, to hypotelorism (close- set eyes) to facial clefts.

Front 53

Name the types of holoprosencephaly

Back 53

Alobar, Semi- lobar, Lobar

Front 54

Sonographic appearance of Alobar holoprosencephaly

Back 54

Most severe form, monoventricle, fused thalami, absence of falx cerebri.

Front 55

Appearance of Semi-lobar holoprosencephaly

Back 55

Partial separation of ventricles & hemispheres with occipital lobe present, incomplete fused thalami.

Front 56

Lobar holoprosencephaly

Back 56

Least severe form, Normal separation of thalami, hemispheres and ventricles, absent cavum septum pellucidum and olfactory tracts.

Front 57

Hydranencephaly

Back 57

Destructive disorder due to bilateral internal carotid artery occlusion or malformation.

Front 58

Hydraencephaly is characterized by

Back 58

Near total lack of cerebral hemispheres with intact and normally developed meninges and skull.

Front 59

Sonographic findings of Hydranencephaly.

Back 59

Large fluid filled cranium (macrocephaly), absent cerebral tissue/ cortical mantle, falx cerebri, normal midbrain and basal ganglia(thalami), polyhydraminos.

Front 60

Dandy- Walker Malformation

Back 60

Complete or partial absence of cerebellar vermis and posterior fossa cystic dilatation communicating with 4th ventricle.

Front 61

What % of fetuses with Dandy Walker have hydrocephalus?

Back 61

80%

Front 62

DWM is associated with

Back 62

Some autosomal recessive syndromes, maternal infection, diabetes melllitus, and exposure to alcohol and Coumadin.

Front 63

Sonographic findings of DWM

Back 63

Complete or partial agenesis of the cerebellar vermis with flattened cerebellar hemispheres, large midline cystic structure in posterior fossa.

Front 64

What is Dandy Walker Malformation associated with

Back 64

Ventriculomegaly and polyhydraminos.

Front 65

How is Dandy Walker Malformation differentiated from subarachnoid Cyst?

Back 65

By contiguity with 4th ventricle.

Front 66

At what fetal age is the corpus callosum complete

Back 66

20 weeks

Front 67

Rate that Agenesis occurs

Back 67

1-3 per 1000 births

Front 68

Sonographic appearance of A genesis of Corpus Callosum

Back 68

Absence of Cavum Septum Pellucidum, elevated dilated 3rd ventricle, widely separated frontal horns of lateral ventricles with enlarged occipital horn, teardrop shaped ventricles displaced upward and outward.

Front 69

Vein of Galen aneurysm

Back 69

Rare arteriovenous malformation (AVM) causing increased floe through vein of Galen.

Front 70

Sonographic appearance of Vein of Galen aneurysm

Back 70

Well defined midline vascular structure superior and posterior to thalamus with turbulent and/or arterial flow.

Front 71

Choroid Plexus Cysts

Back 71

Small cysts within choroid plexus.

Front 72

Choroid plexus cysts have an infrequent association with

Back 72

Aneuploidy specifically Trisomy 18

Front 73

Most common Intracranial tumors

Back 73

Teratomas

Front 74

Lissencephaly

Back 74

Caused by abnormal migration of neurons where the brain lacks sulci and gyri and appears smooth.

Front 75

When is diagnosis made for Lissencephaly

Back 75

3rd trimester

Front 76

What is Lissencephaly associated with?

Back 76

Mild ventriclulomegaly and possible abnormal corpus callosum.

Front 77

Schizencephaly

Back 77

Clefts in the cerebral hemispheres in the region of primary fissures.

Front 78

How does brain appear in Schizencephaly

Back 78

Split into anterior and posterior parts.

Front 79

Porencephaly

Back 79

Presence of cystic areas within the cerebral parenchyma. Cysts vary in size and may communicate with the ventricular system.

Front 80

How is Porencephaly caused

Back 80

Intracranial hemmorhage encephalo malacia.

Front 81

Sonographic appearance of Porencephaly

Back 81

Simple cystic structures within cerebral parenchyma.

Front 82

Microcephaly

Back 82

Decreased head size. More than 3 Standard deviations below the mean.

Front 83

Causes of microcephaly

Back 83

Chromosomal abnormalities and exposure to terratogens.

Front 84

Sacrococcygeal Teratoma

Back 84

Rare tumor arising from the embryonic cells of sacum/coccyx.

Front 85

Grades of Sacrococcygeal Teratoma

Back 85

Three : benign (mature), immature, malignant.

Front 86

Sacroccoccygeal teratomas location

Back 86

External, intrapelvic, intra- abdominal. Frequently hypervascular and consist of cystic and solid components.

Front 87

Sonographic appearance of Sacrococcygeal tetatoma

Back 87

Complex large mass, polyhydraminos,assoc with increased AFP, may have hydrops fetalis.

Front 88

Caudal Regression Syndrome

Back 88

Spectrum of skeletal anomalies of lower spine and limbs (sacral agenesis, lumbar spine and lower thoracic agenesis) 16% associated with diabetes mellitus

Front 89

Scoliosis and Kyphosis

Back 89

Abnormal curvature of spine may involve any segment. MC thoracolumbar region.

Front 90

Scoliosis and Kyphosis associated with which defects

Back 90

Structural (CNS and VATER). Severe curvatures assoc with lethal anomalies( anencephaly, limd body wall complex, amniotic band syndrome)