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252 Cards in this Set

  • Front
  • Back
Transverse imaging of the cranium is known as ______.
occipitotransverse
The upper dome-like portion of the skull w/o the lower jaw or facial parts is known as the:
calvarium
What does the calvarium consist of?
frontal bone
parietal bone
occipital bone
What are the 2 parts of the cranium?
cranial vault & face
When does cranial ossification occur?
12 weeks
The texture characteristics of the cranium are determined by ____ weeks.
18
T or F. Most brain anomalies represent a symmetric process.
TRUE
What are the midline structures of the cranium?
cavum septum pellucidum
corpus collosum
cerebellum & brain stem
3rd & 4th ventricles
What are the 2 lateral structures of the cranium?
lateral ventricle, choroid plexus
The anterior portion of the cranium are the ____ ____.
frontal horns
The posterior portion of the cranium includes what 3 structures?
occipital horns of lateral ventricles
choroid plexus
posterior fossa (cisterna magna)
The echogenic cluster of cells important to the production of CSF is the ____ ____.
choroid plexus
Where is CSF (cerebrospinal fluid) produced?
by the choroid plexus within the lateral ventricles
The choroid plexus is a highly ____ tissue.
vascularized
The choroid plexus appear ____ in early pregnancy.
large
Where is the choroid plexus located?
within the roofs of each ventricle except @ the frontal horns
What are 4 characteristics of the choroid plexus?
echogenic, tear shaped, housed b/t medial & lateral ventricular borders, prominent in early pregnancy
The body of the choroid plexus is the ____.
glomus
What is a common normal variation within the choroid plexus?
cysts
Some CP cysts have a known association with _____ _____.
chromosomal abnormalities (trisomy 18)
The fetal ventricular system consists of what ventricles?
lateral ventricles 1 & 2, and the 3rd and 4th ventricle
What are the 5 regions of lateral ventricles?
frontal horns, lateral bodies, occipital horns, temporal, atria/trigone
The ____ ____ are the most superior regions of the lateral ventricles.
lateral bodies
The most lateral region of the lateral ventricles is the ____ region.
temporal
The juncture of the anterior, temporal, and occipital horns is known as the _____.
atria/trigone
The site for lateral ventricle measurement is @ the _____.
atria/trigone
Two diverging echo free structures within the frontal lobes of the brain are the ____ ____.
frontal horns
The frontal horns become prominent with ____ ____.
ventricular dilatation
This acts as a protective cushion encasing the brain & spinal cord:
CSF
CSF regulates ____ within the spaces it fills.
pressure
Proximal brain structures contain _____ artifacts.
reverberation
The lateral ventricle is more easily imaged in the ____ hemisphere.
distal
The _____ brain structures are better for sonographic evaluation.
distal
What causes reverberation?
sound passing out of a structure w/ acoustic impedance that is different from its neighbor causing alot of sound
How are the lateral ventricles measured?
in the axial plane
To measure the lateral ventricles you would measure across the ____ ____ perpendicular to the long axis of the ventricle.
posterior glomus
The normal measurements of the lateral ventricles are ____ mm or less.
10
What is the average normal measurement of the lateral ventricles?
6.5 mm
You must evaluate for ______ or ______ which are signs of CNS abnormalities.
ventriculomegaly or hydrocephalus
The midline anechoic fluid containing structure is known as the ____ ____ ____.
cavum septum pellucidum
What does the cavum septum pellucidum look like on US?
2 small bright lines separated by CSF & is box shaped
Where is the cavum septum pellucidum located?
parallel to the falx, anterior to the thalamus.
The cavum septum pellucidum lies between the ____ ____ & bodies of the ____ ____.
frontal horns, lateral ventricles
T or F. Viewing the cavum septum pellucidum signifies normal development of the frontal midline.
TRUE
What structure keeps the 2 lateral hemispheres of the cerebrum connected?
the corpus callosum
The ____ ____ is a band of tissue between the frontal ventricular horns.
corpus callosum
The echogenic fibrous structure separating the brain into 2 equal hemispheres is the ____ ____.
interhemispheric fissure (IHF)
The IHF is an important landmark and its presence implies that ____ of the ____ has occurred.
separation of the cerebrum
The ____ are the band of white matter joining different parts of the brain.
peduncles
The intrahemispheric fissure is a ____ echo & the ____ ____ diameter of the skull.
midline, widest transverse
The intrahemispheric fissure is the proper level to measure the ____ & assess midline fetal brain structures.
BPD
There is paired ____ on either side of the intrahemispheric fissure & the apex of them points towards the ____ ____.
thalamus, fetal occiput
The ____ aids in deciding which direction the face is positioned.
thalamus
What ventricle is located within the thalamus?
3rd ventricle
How does CSF travel?
thru choroid plexus to foramen of monro to the 3rd ventricle & aqueduct of sylvius to 4th ventricle
Pulsations from the ____ artery are observed b/t the lobes of the ____ @ the interpeduncular cistern.
basilar, peduncles
The cerebellum is located ____ to the cerebral peduncles in the ____ ____.
posterior, posterior fossa
The vascular network at the base of the brain that may be seen anterior to the midbrain is the:
circle of willis
The circle of willis is a ____ region that is highly ____ in the midline position.
triangular, pulsatile
The ____ ____ artery can be seen as a major lateral branch of the circle of willis.
middle cerebral artery
What is the middle cerebral artery used to evaluate for?
to evaluate for impending fetal demise
What is included within the posterior fossa?
cerebellum, 4th ventricle & cisterna magna (& nuchal fold- SDMS)
The ____ helps to coordinate movements, balance & posture.
cerebellum
Where is the cerebellum located?
w/in the posterior fossa and below the cerebrum & is posterior to the cerebral peduncles
The cerebellum is _____ to most of the brain stem.
superoposterior
What is the cerebellum composed of?
2 lateral hemispheres & the vermis
The small central lobe which relays info b/t the 2 hemispheres is the ____.
vermis
The cerebral hemispheres are joined together by the ____ ____.
cerebellar vernic
The primary reason for TCD (trans cerebellar diameter) is to detect for ____ of the ____.
malformations of the CNS
To measure the cerebellum w/ TCD you must obtain the measurement in the ____ ____ ____ plane.
fetal axial oblique
When measuring the cerebellum you must measure the ____ ____ diameter.
widest transverse
What is the shape of the cerebellum on US when measuring?
dumb bell or heart shape
The cerebellum is typically measured between ____ weeks.
14 - 30 weeks
The cerebellum measurement CAN be used for ____ ____ but not in the presence of an _____.
gestational dating, abnormality
Cisterns are areas where CSF ____.
pools
The ____ ____ is a posterior fossa cistern filled with CSF.
cisterna magna
The largest cistern in the brain is the ____ ____.
cisterna magna
A normal appearing cisterna magna may exclude almost all open ____ ____.
spinal defects
The cisterna magna is an ____ structure located ____ to the cerebellum.
anechoic, posterior
Linear echoes in the cisterna magna represent ____ ____ that attach the ____ ____.
dural folds, falx cerebelli
What are the normal measurements of the cisterna magna?
3 - 11 mm
The average size of the cisterna magna is:
5 - 6 mm
How do you measure the cisterna magna?
measure from the vernis to the inner skull of the occipital bone
The nuchal fold is NOT assessed in the ____ view.
sagittal
What view is the nuchal fold assessed?
axial
Nuchal skin fold thickness is measured in the ____ trimester up to ____ weeks.
2nd, 20
The nuchal fold is measured in the plane containing what 3 structures?
cavum septum pellucidum, cerebellum, cisterna magna
The normal range of nuchal fold measurements is ____.
less than 6 mm ( .6 cm)
What are 4 other structures that may be measured to estimate GA?
cerebellar length
binocular distance
renal length
humerus length
1st trimester:
CRL +/- (3-5 days)
14 - 20 weeks
BPD, HC, AC, FL +/- 10 days
20 - 30 weeks
BPD, HC, AC, FL +/- 14 days
30 - 40 weeks
BPD, HC, AC, FL +/- 21 days
A tool used for GA determination is called _____ height.
symphysis-fundal
The first fetal motion felt by the mother is known as ____ & is used for GA determination.
quickening
What can cause increased fundal height?
macrosomic fetus
polyhydramnios
twins, incorrect dates
fibroids, molar pregnancy
Decreased fundal height may be caused by:
SGA or IUGR fetus
oligohydramnios
incorrect dates
The measure of variation that is generally the most important & useful is:
standard deviation
What is standard deviation?
the measure of variation of values about the mean
Written representation by graphs, diagrams or charts w/ numbers is known as a _____.
nomogram
What are the 4 basic GA measurements?
BPD, HC, AC, and FL
What does BPD stand for?
biparietal diameter
The BPD is obtainable at ____ weeks TA.
10 - 12
The BPD is not typically measured until ____ weeks.
12
What 3 planes are used for BPD?
axial, transverse, or thalamic
What are the 3 landmarks used for BPD?
cavum septum pellucidum
thalamus
cerebral peduncles
Do not include ____ ____ when measuring BPD.
soft tissue
How do you measure the calvarium (parietal bone)?
from leading edge to leading edge
The most common way to measure the calvarium is ____ edge to ____ edge.
outer to inner
BPD reliability decreases after ____ weeks due to increased ____ ____.
26, biologic variability
BPD accuracy is greatest between _____ weeks and is affected by ____ shape.
12 - 28 (+/- 2, or 3 in 3rd trimester), head
BPD is not accurate with what 3 things?
severe ventriculomegaly
microcephaly
skull altering head lesions
BPD growth is ____ mm per week in the early 2nd trimester & ____ mm in the mid 2nd trimester.
5 mm, 3.6 mm
BPD growth is ____ mm per week in the 3rd trimester.
1.8 mm
The BPD is found at the level of ____ ____ ____.
midline echo complex
What are the 2 landmarks for BPD?
smooth symmetric head & well defined midline echo
A normal head shape is ____.
ovoid
A round shape head is called:
brachycephaly
Brachycephaly leads to _____ of GA.
overestimation
A flattened head is known as:
dolichocephaly
Dolichocephaly leads to ____ of GA.
underestimation
Dating by HC is unaffected by ____ ____.
head shape
Near term HC is more accurate than ____.
BPD
To measure HC you measure at the ____ level.
BPD
How do you measure HC?
from outer to outer border
What is the HC formula?
(D1 + D2) x 1.57
Measurement along the outer perimeter of the calvarium is known as ____ ____.
ellipse calculation
T or F. Prenatal compression of the head is normal
TRUE
The ____ is less affected by compression than ____.
HC, BPD
What are 4 reasons for head compression?
malpresentation
uterine crowding
vertex position
leiomyoma (fibroids)
The ____ ____ evaluates head shaped for the reliability of BPD.
cephalic index
The cephalic index is performed to determine ____ ____.
head shape
The ratio of the BPD to fetal anterior-posterior diameter of the fetal skull is:
cephalic index
What does OFD stand for?
occipito-frontal diameter
What is the formula for cephalic index?
CI= BPD/OFD x 100
Abnormal cephalic index values may indicate what 2 things?
dolichocephaly
brachycephaly
How do you measure OFD?
measure from the outer border of the occiput to the outer border of the frontal bone
What is a normal cephalic index (CI)?
80% +/- 1

range is 75-85%
With dolicocephaly there is a small ____ and longer ____.
BPD, OFD
The cephalic index is ____ with dolicocephaly.
< 75%
Dolicocephaly is associated with ____ fetuses and ____.
breech & oligohydramnios
With brachycephaly there is a large ____ and shorter ____.
BPD, OFD
The cephalic index is ____ with brachycephaly.
> 85%
Brachycephaly is most commonly a ____ ____.
normal variant
Two associations with brachycephaly are:
trisomy 21 & spina bifida
The condition of having a malformed cranial vault with a peak appearance & vertical index above 77 is ______.
oxencephaly
What is oxencephaly caused by?
premature closure of the coronal, sagittal, and lambdoidal sutures
Face visualization is dependent on what 3 things?
fetal position
adequate amniotic fluid
good acoustic windows
What does a transverse view of facial anatomy demonstrate?
orbital abnormalities
intra-orbital distances
maxilla
mandible
The orbits are inferior to or below the ____ ____.
cerebellar plane
The ocular diameter (OD) is the measurement of a ____ ____.
single orbit
How do you measure OD?
from medial to lateral wall of orbit
The inner orbital diameter (IOD) is the length between ____ ____.
two orbits
How do you measure IOD?
from medial wall of one orbit to the medial wall of the other
The binocular distance (OOD or BD) is the ____ to ____ orbital diameter.
outer to outer (lateral to lateral)
The _____ measurement is more strongly related to BPD & GA than other orbital measurements.
binocular distance (OOD or BD)
Orbits are accessible in all fetal positions except:
face down
Ocular biometry is helpful in identifying what 4 things?
hypotelorism (close orbits)
hypertelorism (spaced orbits)
anophthalmia (absent eyes)
micropthalmia (small eyes)
Of the 4 basic GA measurements the ____ has the largest reported variability & is more affected by growth disturbances.
AC (abdominal circumference)
The ____ is most susceptible parameter to measurement error.
AC
The ____ size strongly influences AC.
liver
T or F. AC is a poor predictor of GA later in gestation.
TRUE
The term for large fetus is ____.
macrosomia
The equation for AC is:
(D1 + D2) x 1.57 = AC
To measure the AC in TRV you must use what 2 landmarks?
level of umbilical vein & portal sinus junction
(stomach & adrenal glands may be seen at this level)
T or F. The AC includes the entire perimeter of the abdomen including soft tissue.
TRUE
A high AC/HC ratio implies ____ of the fetus.
malnutrition
The ____ length has the same accuracy as BPD measurements predicting GA.
femur
You must measure the femoral ____ from end to end.
diaphysis
What is the diaphysis?
shaft of a long bone
When measuring the femur what 3 things are not included with the measurement?
cartilaginous epiphysis, femoral head, distal femoral point
The ____ is the end of a long bone.
epiphysis
What is associated with advanced gestational age?
distal femoral & proximal tibial epiphyseal ossification centers
The distal femoral epiphyseal ossification center (DFE) is identified with gestations > than ____ weeks.
33
The proximal tibial epiphyseal ossification center (PTE) is identified with gestations > than ____ weeks.
35
What should be done if there is a 2 week or > measurement discrepancy b/t the femur & other biometric parameters?
all fetal long bones should be measured
The ____ ____ ____ may produce specular reflections that should not be included in the humerus measurement.
cartilaginous humeral head
The ____ ____ ____ should also not be included when measuring the humerus.
proximal humeral point
The ulna is ____ than the radius proximally but distally it is ____ to the radius.
larger, equal
The ____ is on the fetal thumb side.
radius
The tibia is ____ to, ____ & ____ than the fibula.
medial, longer, thicker
The fibula is ____ to the tibia.
lateral
When the EFW is above the 90th percentile for EGA it is considered to be:
macrosomia
If the EFW is below the 10th percentile for EGA it is considered to be:
IUGR
Another name for an exceptionally large baby (fat baby) is called:
macrosomia
206.7
This is the most widely recognized and most common stress reaction?
alcohol consumption
The frequency of macrosomia in the offspring of diabetic mothers ranges from _____.
25% - 45%
When a fetus has macrosomia they have a birthweight > than ____.
4,000 grams
The placenta of the macrosomic fetus can become significantly ____ & ____.
large & thick
The most reliable sonographic assessment for macrosomia is ____ ____.
abdominal circumference
What are the 3 main complications associated with macrosomia?
fetal shoulder dystocia
increased mortality & morbidity
prolonged labor
What are 4 conditions potentially affecting fetal growth?
severe pre-eclampsia
chronic hypertension
chronic renal disease
severe diabetes
What does EFW stand for?
estimated fetal weight
A normal but smaller fetus is known as ____.
SGA (small for gestational age)
What is a SGA fetus likely to have?
small placenta & low AFI
A fetus with IUGR is a subset of ____ fetuses.
SGA
IUGR is associated with:
SGA
maternal hypertension
preeclampsia
decreased fetal movement
What are the 2 types of IUGR?
symmetric & asymmetric
For an accurate assessment with prior dating, ____ ____ are required.
serial exams
What are some risks & complications associated with IUGR?
asphyxia
meconium aspiration
low birth weight
stillborn/illness
Symmetric IUGR makes up ____% of all IUGR cases.
25% - 30%
Asymmetric IUGR is the more common form and makes up ____%
70% - 75%
With symmetric IUGR all physical parameters are ____ in size.
decreased
Symmetric IUGR is associated with ____ ____ in the ____ trimester.
severe insult, 1st
Head sparing IUGR typically begins in the ____ or ____ trimester.
2nd or 3rd
The most common cause of asymmetric IUGR is ____ ____.
placental insufficiency
What are the 4 placental factors with asymmetric IUGR?
placental insufficiency
abruptio placenta
infarcts
placental neoplasms
What are 3 fetal factors with asymmetric IUGR?
isoimunization
multiple gestation
congenital anomalies
IUGR is an indication for ___ ___ ___.
umbilical cord doppler
With monochorionic twins the EFW should be concordant & not differ by more than ____%.
20%
What is the formula for determining EFW discordance?
Largest EFW - smallest EFW/Largest EFW x 100
The assessment of fetal well being or distress is known as the:
BPP (biophysical profile)
When is a BPP performed?
after 28 weeks GA
BPP has ____ parameters worth ____ pts each.
5, 2
What are the 5 parameters for BPP?
cardiac non stress test
observation of breathing
fetal movements & fetal tone
amniotic fluid
There is a ___ min time limit with BPP.
30
A BPP score of ____ is considered normal.
8 - 10
With a cardiac non stress test the BP is taken every ____ min.
8 - 10
What patient positions are used for a cardiac non stress test?
lateral recumbent, semi-fowlers
A NST may be performed 2 times a week on patients with ____, ___, or ____.
diabetes
IUGR
postdate
Fetal breathing must be observed for ____ seconds continuously.
30
How many points are given for one episode of breathing lasting 30 seconds? If not seen?
2 points, 0 points if not visualized
The fetal ____ initiates & regulates frequency of fetal breathing movements.
CNS
At least ___ discrete body movements must be visualized.
3
The ____ ____ system controls fetal body movements.
intact nervous
At least ____ episode of extension or flexion of limbs must be observed.
1
A normal amniotic fluid rating is one pocket of amniotic fluid @ least ____ cm or AFI total fluid measurement of ____ cm.
2 cm , 5-22 cm
Decreased amniotic fluid may represent ____ or ____ ____.
IUGR, or intrauterine stree
A decrease in blood to the kidneys causes a decrease in ____.
AFI
What is the L/S ratio?
lecithin/sphingomyelin ratio
Testing of the amniotic fluid to determine fetal lung maturity is known as the:
L/S ratio
Lecithin exceeds sphingomyelin by a _____ ratio.
2:1
A ____ ____ doppler is not recommended for routine fetal evaluation.
umbilical artery
What are the indications for doing a uterine artery doppler?
abnormal biophysical profile
abnormal AFI
IUGR
multiple gestation
Umbilical artery doppler studies should be avoided during ____ ____.
fetal breathing
Diastolic flow is directly related to the flow resistance of the ____.
placenta
What does umbilical artery doppler measure?
the resistance of blood flow within the placenta.
As a pregnancy progresses, the resistance to flow ____.
decreases (due to increased numbers of tertiary stem villi)
Blood flow in the umbilical artery increases during ____.
diastole
End diastolic flow increases with ____ ____.
gestational age
Absence of effective diastolic flow is associated with ____ ____.
poor outcome
What are 2 serious findings with umbilical artery doppler?
absent end diastolic flow & reversed end diastolic flow
What is associated with the return of end diastolic flow in the umbilical artery?
prenatal glucocorticoid (used to prolong pregnancy)
Normal S/D ratio is less than ____ ratio during the 3rd trimester.
3:1
What is the formula for resistive index (RI)?
max systolic veloctiy- diastolic velocity/ systolic velocity
What is the normal range of resistive index?
0.45 - 0.58 after 26 weeks gestation
Low resistance has ____ diastole.
increased
High resistance has ____ or ____ diastole.
decreases or reversed
What type of flow is desirable for umbilical cord doppler?
low resistance flow
High resistance flow feeds a high resistance vascular bed including the ____ & ____ extremities.
uterus & face
Two examples of low resistance vascular beds include the ____ & ____.
brain & organs
What is the most severe doppler finding?
complete reversal of end-diastolic velocity