head/brain

Question 1

what dies MSAFP stand for?

Answer 1

maternal serum alpha-fetoprotein

Question 2

greater than 2.5 standard deviations from the median is abnormal & suggests what?

Answer 2

an open neural tube defect (NTD)

Question 3

an increased fundal height raises suspicion for?

Answer 3

polyhydramnios

Question 4

what is associated with a lemon shaped head?

Answer 4

spina bifida

Question 5

a strawberry shaped head is associated with what?

Answer 5

trisomy 18

Question 6

brachiocephy is a rounded head shape

true/false

Answer 6

true

Question 7

what is brachiocephaly associated with?

Answer 7

chromosomal abnormalities

genetic syndromes

Question 8

dolicocephaly is generally due to head molding in the vertex position
true/false

Answer 8

false; breech position

Question 9

what is ventriculomegaly?

Answer 9

ventricular enlargement characterized by excessive CSF w/in cerebral centricles

Question 10

what are some things that can cause ventriculomegaly?

Answer 10

obstruction to outflow (hydrocephalus)
decreased CSF absorption
overproduction of CSF

Question 11

what is hydrocephalus?

Answer 11

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

Question 12

the atrium of the lat vents shoukd not exceed:

Answer 12

10 mm

Question 13

what is the most common type of intraventricular obstruction?

Answer 13

aqueductal obstruction (stenosis)

Question 14

what are the other types of intraventricular obstructions?

Answer 14

chiari II malformation

dandy walker malformation

Question 15

what is a cause for extraventricular obstruction?

Answer 15

arachnoid cyst

Question 16

what are some additional anamalies that may be present with ventriculomegaly?

Answer 16

spina bifida
dandy walker syndrome
encephalocele
cardiac malformations
renal malformations
abnormal karyotypes

Question 17

what is the sonographic appearance of ventriculomegaly?

Answer 17

excess fluid in lateral & 3rd vents
atrium greater than 10mm
choroid plexus may dangle w/in CSF

Question 18

what are some other associated so ographic findings of ventriculomegaly?

Answer 18

polyhydramnios
abnormal fetal lie
hepatomegaly & fetal ascites
meningomyelocele

Question 19

what may be present with anencephaly?

Answer 19

portions of the midnrain & brain stem

Question 20

what are some other features of anencephaly?

Answer 20

buldging eyes
macroglossia
very short neck
AFP will be elevated

Question 21

with anencephaly, the face & orbits will be present, giving the face what type of appearance?

Answer 21

frog-like

Question 22

what are some other sonographic findings associated with anencephaly?

Answer 22

• major portions of cranium & intracranial strctures are absent
• polyhydramnios
• talipes (club foot) also a common finding

can be diagnosed as early as 12wks

Question 23

a bony defect in the skull allows herniation of intracranial contents. what are those types of herniations called?

Answer 23

cranial meningocele

encephalocele

Question 24

encephalocele contains only meninges & CSF

true/false

Answer 24

false; contents inclue brain & CSF

Question 25

what is the most common site for a herniation of the skull? what are the other sites?

Answer 25

occipital frontal parietal

Question 26

what could cause an encephalocele?

Answer 26

amniotic bands

Question 27

what is the sonograhic appearance of an encephalocele?

Answer 27

may be cystic near the cranium | brain tissue may be present w/in the mass

Question 28

what is holoprosencephaly?

Answer 28

incomplete cleavage or diverticulation of primitive forebrain into 2 hemispheres

Question 29

what is holoprosencephaly strongly associated with?

Answer 29

trisomy 13

Question 30

what are the 3 classifications of holoprosencephaly?

Answer 30

alobar semilobar lobar

Question 31

which is the most severe form of holoprosencephaly? a. semilobar b. a bar c. lobar d. alobar

Answer 31

d. a lobar | * lacking 2 hemispheres*

Question 32

what brain structures are absent with alobar?

Answer 32

falx corpus callosum cavum septum

Question 33

what are the facial abnormalities associated with alobar?

Answer 33

hypotelorism cyclopia midline facial clefts

Question 34

semilobar resembles lobar | true/false

Answer 34

false; it resembles alobar

Question 35

what facial abnormality is associated with semilobar?

Answer 35

cleft lip/palate

Question 36

what is the least severe form of holoprosencephaly? a. alobar b. the bar c. lobar d. semilobar

Answer 36

c. lobar | * 2 hemispheres are present*

Question 37

what is dandy-walker complex?

Answer 37

congenital malformation of the posterior fossa, specifically the cerebellar vermis

Question 38

what is dandy-walker malformation?

Answer 38

small or absent cerebellar vermis | cisterna magna enlargement

Question 39

which of the following is a variant of dandy-walker? a. arnold-walker b. vermian hypoplasia c. dandy hyperplasia d. vermian hyperplasia

Answer 39

b. vermian hypoplasia

Question 40

why is it not possible to diagnose vermian hypoplasia until after 18wks?

Answer 40

vermis not developed until 18wks

Question 41

what are other associations of dandy-walker?

Answer 41

ventriculomegaly agenesis of corpus callosum spina bifida microcephaly

Question 42

what is the sonographic appearance of dandy-walker?

Answer 42

* complete or partial agenesis of the cerebellar vermis | * cisterna magna enlargement (>10mm)

Question 43

what is arnold chiari type II malfirmation?

Answer 43

displacement of cerebellar vermis, 4th ventricle, & medulla oblongata through the foramen magnum into the upper cervixal canal

Question 44

what is arnold chiari II frequently associated with?

Answer 44

spinal dysraphia

Question 45

cerebellum will be compressed against the back of the cranium demonstrating what sign?

Answer 45

banana sign

Question 46

what is microcephaly?

Answer 46

small head circumference measuring more than 3 standard deviations below the normal

Question 47

what is associated with microcephaly?

Answer 47

intrauterine infections aneuploidy/syndromes underlying CNS anomaly

Question 48

what is the sonographic appearance of microcephaly?

Answer 48

``` small BPD decreased HC/AC ratio poor cranial growth in serial scans no definitive nasal/forhead differentiation high false positive rate ```

Question 49

the corpus callosum is the smalles neural tract connecting the cerebral hemispheres true/false

Answer 49

false; it's the largest

Question 50

what is agenesis of the corpus callosum (ACC)?

Answer 50

the failure of the development of the corpus callosum that may be partial or complete

Question 51

what other abnormalities are commonly associated with ACC?

Answer 51

``` trisomies (especially 18 & 13) holoprosencephaly median facial clefts dandy-walker other syndromes or CNS anomalies (schizencephaly or lissencephaly) ```

Question 52

what are some clinical associations of ACC?

Answer 52

isolated ACC may be asymptomatic low intelligence seizures poor motor coordination

Question 53

what is the sonographic appearance of ACC?

Answer 53

* disproportionate enlargement of occipital horns (colpocephaly) * lateral displacement of both medial & lateral ventricular walls * widely separated lateral ventricular frintal horns * ventricles may demonstrate teardrop shape * absence of cavum septum pellucidi

Question 54

the vein of galen aneurysm is a true aneurysm | true/false

Answer 54

false

Question 55

what is hydranencephaly?

Answer 55

destructive process causing total or near total absence of cerebrum it is the most severe degree of porencephaly or brain destruction

Question 56

what is the MOST common cause of hydranencephaly?

Answer 56

occlusion of the carotid arteries in the first or early second trimester

Question 57

what is the sonograohic appearance of hydranencephaly?

Answer 57

* head size commonly normal but can be small or large * falx is present but may be displaced or hypoplastic * variable presence of 3rd vent * may be difficult to distinguish from a severe hydrocephaly

Question 58

what destructive process crates a cleft in the cerebral cortex? a. hydrancephaly b. lissencephaly c. spina bifida d. schizencephaly

Answer 58

d. schizencephaly

Question 59

what is the sonographic appearance of schizencephaly?

Answer 59

fluid-filled clefts in the cerebral cortex that can be uni/bi lat

Question 60

what is associated with schizencephaly?

Answer 60

midline brain defects ventriculomegaly septic optic dysplasia agenesis or dysgenesis or the corpus callosum absence of septum pellucidum heterotopias (displacement of gray matter) polymicrogyria (many folds on surface of brain)

Question 61

lissencephaly has a smooth brain surface with normal sulci & gyri true/false

Answer 61

false; it does not have sulci & gyri

Question 62

when is lissencephaly usually diagnosed?

Answer 62

third trimester

Question 63

what is associated with lissencephaly?

Answer 63

agenesis of corpus callosum dandy-walker colpocephaly

Question 64

what are porencephalic cysts?

Answer 64

cysts filled with CSF that communicate w/ the ventricular system

Question 65

are choroid plexus cysts malignant or benign?

Answer 65

benign