Second & Third Trimester
the double line appearance of the spine in the coronal section is also termed what?
"railway sign"
What is the base protocol for an obstetric sonography examination?
-observe fetal viability by visualization of cardiovascular pulsations -demonstrate presontation (fetal lie) -demonstrate the number of fetuses -Amniotic fluid -Characterize the placenta -Visualize the cervix -Assess fetal age
First trimester: Second trimester: Third trimester: Postterm pregnancy:
0-12 weeks 13-26 weeks 27-40 weeks >40 weeks gestation
What score on the BPP indicates either immediate delivery or extending the test to 120 minutes?
0-2
Amniotic fluid pocket less than _________ to _______cm may represent IUGR
1-2cm
The heart occupies approx. ______ of the chest cavity
1/3
Lateral ventricles should never exceed how many mm?
10 mm
IUGR is most commonly defined as a fetal weight at or below ____% for a given gestational age
10%
By the ____th week of gestation, the cranial bones ossify
12
As a general rule in early pregnancy (approximately _____ to _____ weeks), the LVB appears to be large in relationship to the developing cranial hemispheres. Later in pregnancy, the LVB assumes a more ________ position.
12 22 medial
Orbital diameter increases from ____ mm at 12 weeks to ____ mm or greater at term
13 59
When is an Amniocentesis performed?
14-20 weeks
By ____ weeks of gestation, the texture characteristics of each brain structure have been determined. From this point on in the pregnancy, the appearance of each brain structure should _________________________.
18 remain the same
Polyhdraminos is considered when the AFI is >____________cm
22cm
EHR can be measured by M-mode from early fifth to early ninth gestational weeks when CRL <____ mm
25
Ovulatory age is approximately ______ days (_____ weeks), as ovulation generally occurs on the 14th day of the menstrual cycle.
288 38
What trimesters are ideal times to image fetal anatomy?
2nd and 3rd trimesters
The normal cisterna magna measures from _____ to ____ mm
3 to 11 mm With an average size of 5-6mm
Femur usually lies at ____ to _____ degrees to the long axis of the fetal body.
30 70
How long is a fetal biophysical profile?
30 minutes.
Preterm babies are any babies born prior to _________________ menstrual weeks.
38
Term babies are born between _________ and ___________ menstrual weeks
38 and 42
Ovulatory age is approx ______ weeks as ovulation generally occurs on the 14th day of the menstrual cycle.
38 weeks
In what trimester is BPD not as accurate in predicting fetal age?
3rd trimester
TVS—when CRL measures ___ mm, embryo should demonstrate cardiac function
4
A defect in L___ and L___ indicates spina bifida
4 5
Most major anomalies of the fetal heart are excluded when cardiac anatomy appears normal in the _______________ view of the heart.
4-chamber
fundal height drops at approx. ____ weeks
40
The length of the average human pregnancy is _____ weeks (_____ days) beginning from the first day of the last menstrual period (LMP).
40 280
The length of an average human pregnancy is _____ weeks beginning from the first day of the __________.
40 weeks, LMP
Possterm babies, are any babies born later than _____________ weeks
42 weeks
Oligohydraminos is considered when the AFI is < ____cm
5 cm
When we have a measurement of what bhCG should we see a Gestational sac?
500 mIU/ML
Pregnancy can be clinically detected approximately ___ to ___ days after ovulation
6 8
The normal ventricle measures________mm
6.5 mm
After ____ weeks YS and GS diverge from one another
7
Absence of an embryo by ____ to ____ weeks' gestation is consistent with a blighted ovum or an anembryonic pregnancy
7 8
Cardiac activity should be seen when the CRL exceed ____ mm
7mm
CRL should increase at a rate of ____ mm per day.
8 mm per day
What are normal AFI values?
8 to 22 cm
What SCore for the biophysical profile (BPP) is considered normal?
8-10
If a yolk sac is greater than _____mm it is considered abnormal.
8mm
______________ is more useful as a growth parameter than in predicting gestational age: IE: Weight.
AC
How many gross body movements should be seen in the 30 minute biophysical profile?
AT least 3 unprovoked
Nagele's Rule:
According to this method, the EDC is derived by subtracting 3 months from the LMP and adding 7 days
What is Nagele's rule?
According to this method, the EDC is derived by subtracting 3 months from the LMP and adding 7 days EDC= LMP - 3 months + 7 days
What is Fetal tone? How should fetal tone be measured during a bipophysical to be considered normal?
Active extension and flexion at least 1 episode of limbs or trunk
What can kidneys be mistaken for?
Adrenal Glands
What is it called when we sample fluid within the amniotic sac?
Amniocentesis
What does AGA stand for?
Appropriate for Gestational Age
When can pregnancy be clinically detected?
Approx 6-8 days after ovulation
How do fluid filled fetal lungs appear sonographically?
As solid homogeneous masses of tissue bordered medially by the heart and inferiorly by the diaphragm and laterally by the rib cage.
If you suspect IUGR what should you look for in the umbilical artery?
Assess umbilical artery doppler for increased resistance to flow
In the second trimester the Gestational age parameters include:
BPD HC AC FL
What are some measurements taken during 2nd and 3rd trimester ultrasounds?
BPD Head Circumference FL (femur length) HL (Humerus Length) AC (Abdominal circumference) *fetal weight*
The most reliable EFW incorporate all fetal parameters such as:
BPD, HC, AC, FL, HL
What are measurements used to determine fetal weight?
BPD, HC, AC, FL, HL
Assymmetrical IUGR begins in which trimester? What does it result from?
Begins late in the second or third trimester resulting from placental insufficiency
What is the BD diameter?
Binocular diameter Measure outer to outer diameter
Absence of an embryo by 7 to 8 weeks gestation is consistent with a _____________ ________ or an ____________ pregnancy.
Blighted ovum Anembryonic
If you view high end diastolic flow in the middle cerebral artery what should you suspect?
Brain sparing effect associated with IUGR
A ______ presentation the body is closest in proxim8ity to the direction of the cervix and the cranium is directed toward the uterine fundus.
Breech
By what week of gestation do the cranial bones ossify?
By the 12th week
Spinal views include what parts of the spine?
C-spine 5-7vert T-spine 12 vert L-spine 5 vert Sacrum (look for sacral curvature)
In first trimester what is the most accurate fetal age measurment?
CRL Can be measured from 6-12 weeks GA by transvaginal sonography
The cisterna magna (a posterior fossa cistern filled with _________) lies directly behind the cerebellum.
CSF
The presence of the ______________ signifies normal development of the frontal midline
CSP
What should the sonographer note in the four chamber view of the fetal heart?
Cardiac position Proper situs Axis
What can we measure in the posterior fossa?
Cerebellum Cisterna Magna Nuchal fold
What should an image of the posterior fossa of the fetal head include? (3)
Cerebellum Cisterna Magna nuchal skin fold
3 steps when evaluating the cranium in the long axis:
Check contour or outline of skull bone Fetal profile Brain Anatomy
When we want to sample trophoblastic tissue what is it called? when is this performed?
Chorionic Villi Sampling (CVS) 9-10 weeks
A normal appearing ____________ may exclude almost all open spinal defects.
Cisterna Magna
By viewing the CSP what anomaly may be excluded?
Complete agenesis of corpus callosum (Absence of the white matter that holds the two brain hemispheres together)
With which breech presentation does the baby need to be delivered by Cesarean section?
Complete breech
______________ breech is when both the hips and lower extremities are found in the lower pelvis.
Complete breech
What are the variations of the breech position?
Complete breech, Incomplete breech Frank Breech
What is another name for PUBS?
Cordocentesis
Fetal spine is studied in what scanning planes?
Coronal, sagittal, and transverse
What are two clinical signs of IUGR?
Decreased fundal height and fetal motion
What might be some causes of Asymmetrical IUGR occurring in late second or third trimester?
Diabetes Chronic hypertension cardiac or renal disease Abruptio placenta Multiple pregnancy Smoking Poor weight gain Drug usage Uterine anomaly
At approximately 4 weeks, menstrual age, a small hypoechoic area appears in the fundus or midportion of the uterus and is known as the _________________ sign.
Double decidual sac sign
What does EFW stand for?
Estimated Fetal Weight
What does EDC stand for?
Estimated date of confinement (or due date)
What measurement are used in a biophysical profile?
FBM (Fetal breathing movement) Gross body movement Fetal tone FHR (Fetal heart rate) AFI (Amniotic fluid index)
The most widely measure and easily obtainable of all fetal long bones is the ______________
Femur
____________ length may indicate skeletal dysplasia or IUGR.
Femur
What does FBM stand for?
Fetal breathing movement
What should not be in the pocket of amniotic fluid measured?
Fetal limbs or umbilical cord loops
Oligohydraminos has been associated with:
Fetal renal anomalies Rupture of the intrauterine membranes Posdate pregnancy
_______________ is lateral to tibia and thinner.
Fibula
Incomplete breech is also known as what?
Footling breech.
What position would this be describing: Fetus with head toward fundus and both legs extended upward toward fundus.
Frank Breech
How do you measure cerebellum?
From outside to outside of the "lazy 3"
What does G4P2103 mean?
G4= 4 pregnancies P: 2= Full term deliveries 1= premature births 0= abortions 3= living children
Key IUGR sonographer markers are:
Grade 3 placenta before 36 weeks or decreased placental thickness
number of pregnancies, including the present one:
Gravidity
What two measurements in particular are especially useful in differentiating symmetrical vs asymmetrical IUGR?
HC and AC ratio
__________________________________ is used in cases in which head to abdomen disproportion is suspected or unusual head or body contours are observed
Head circumference to abdominal circumference ratio
What is Brachycephaly?
Head is elongated in the transverse diameter (BPD) and shortened in the AP diameter (OFD)
What are some maternal factors for IUGR?
History of previous IUGR Significant maternal hypertension Smoking Presence of uterine anomaly (large leiomyoma, bicornuate uterus) Significant placental hemorrhage
The goal of the BPP is to find a way to predict and manage the fetus with ________________.
Hypoxia
The gradual _________________________ concept states that neural activity arising in distinct anatomic sites in the brain controls dynamic biophysical activities (FT, FM, FBM and FHR reactivity)
Hypoxia
__________________ is described as a decreased rate of fetal growth.
IUGR
What are two indications for an amniocentesis?
Increased AFP History chromosomal or genetic disorders
Doppler ultrasound has shown that in fetuses with asymmetric IUGR, vascular resistance _______________________ in the aorta and umbilical artery and ____________________ in the fetal middle cerebral artery.
Increases; decreases
What different ways can the fetal spine be positioned?
Inferior, superior, anterior, posterior
What is the IOD?
Inner orbital diameter Measure inner to inner
What does IUGR stand for?
Intrauterine growth restriction
When looking at fetal breathing an alternative area to watch for breathing is fetal ____________ movement in the long plane.
Kidney movement
To determine female genitalia what do you look for?
Labia
How do we measure gestational sac?
Long and Transverse we measure inner to inner in both planes
What types of Lie can the baby be in?
Longitudinal Transverse Oblique
During Ultrasound we should examine uterus, adnexa, and cervix to exclude masses. ____________ ______________ may not be visualized during the second and third trimesters of pregnancy.
Maternal Ovaries
Why is BPD not a good predictor or IUGR?
May be normal size due to the brain-sparring effect Potential alteration in fetal head shape secondary to oligohydraminos
How do we measure femur length?
Measure femur from the major trochanter to the external condyle. After 32 weeks the distal femoral epiphysis is seen but not included in the femur length measurement.
How do we measure HC?
Measure twice at level of the BPD Calipers placed outer to outer
Where is the Cavum septum pellucidum located?
Midline falx, small cystic space in falx cerebri
Should the glomus fill the entire ventricle?
NO
If proper plane is used to obtain AC, should fetal kidneys be seen?
No
Should CRL include limbs and/or yolk sac?
No
What is the FHR test also known as during a biophysical?
Non-stress test
What is a normal score in a fetal biophysical profile? What is an abnormal score?
Normal is 2 Abnormal is 0
what are the parameters for obtaining BPD?
Obtained by leading edge to leading edge of diameter of fetal head at transverse level of midbrain. Should see: Flax, CSP, thalamus
If the fetus cannot urinate what occurs?
Oligohydraminos
It is important to recognize the usual configuration of the cerebellum, because distortion may represent findings such as?
Open spina bifida "known as banana sign" Cerebellum may be small or displaced downward into the foramen magnum
With humerus measurement only the humeral shaft (diaphysis) ossified and measured, do not include the _____________
PHP Proximal humeral point
described as using a numeric system describing all pregnancy outcomes
Parity
What does PUBS stand for? what is PUBS?
Percutaneous Umbilical Blood sampling Sampling of blood via the umbilical cord
When looking at pocket of amniotic fluid for measurement, the transducer must be _____________________ to the center of the pocket of fluid in the center of the screen.
Perpendicular
If the fetus cannot swallow what occurs?
Polyhydraminos
Normal protocool for second and third trimesters:
Position of fetus Cardiac Activity Anatomy Measurements The placenta, amniotic fluid, uterus, and adnexa are also examined
If we see little to no cisterna magna with bannana shaped cerebellum what should we suspect?
Possible spina bifida or spinal defect
In transaxial image of the head if we angle the transducer inferior towards the base of the skull we image the ___________ fossa.
Posterior fossa
What views of the fetal heart should be obtained?
RVOT LVOT 4ch
Qualitative measurements include:
S/D ratio (utilized in umbilical artery) RI (utilized in renal arteries) Pulsatility index
What is a coelocentesis?
Samping of exocoelomic cavity via a transvaginal approach.
What is a Culdocentesis?
Samples fluid from the posterior cul-de-sac via Transvaginal approach
Where should we measure AC? What landmarks should we see?
Should be taken from round transverse image perpendicular to fetal spine. Should view spine, stomach, and LPV
What do SGA and LGA stand for?
Small for gestational age Large for gestational age
When viewing transverse section of the abdomen and looking for stomach, what structures should be in the image?
Stomach Umbilical vein Spine
What are the two classifications of IUGR?
Symmetric Assymmetric
This type of IUGR is usually the result of a first trimester insult such as a chromosomal abnormality.
Symmetrical IUGR
In general two types of brain tissues are highly echogenic, the _________ and the _______________ which covers the inner and outer brain surfaces.
The Dura and pia arachnoid
Quantitative doppler flow looks at measurements in blood flow and velocity, whereas Qualitative measurements look at:
The characteristics of the waveform that indirectly approximate flow and resistance to flow
What may be seen anterior to the midbrain and appears as a triangular region?
The circle of willis
What part of the bone is not included in the femur measurement?
The distal femoral epiphysis
What is Dolichocephaly?
The head is shortened in the transverse plane (BPD) and elongated in the AP plane (OFD)
What is the brain sparing effect?
The last organ to be deprived of essential nutrients is the brain. So baby may have abnormal measurements on AC, FL, HL but correct size of BPD and HC Dilation of the fetal intracranial vessels, namely the middle cerebral artery which provides protected blood flow to the brain at the expense of other organs
What is fetal lie described in relation to?
The maternal long axis
Which one is longer Tibia or fibula?
Tibia is longer than fibula
What is the method of dividing the uterine cavity into 4 equal quadrants to measure the largest vertical pocket of fluid used for?
To derive AFI (Amniotic fluid index) AFI is the sum of the four quadrants
Where is the nuchal skin fold?
Toward the back of the head, skin fold behind the nape of the neck
When a transverse cross-section of the fetal head or body is noted in the sagittal plane, a ___________ lie should be considered.
Transverse
In the ___________ plane the spinal column appears as a closed circle.
Transverse plane
What does a cystic hygroma indicate?
Turner's syndrome
Which one is longer: ulna or radius?
Ulna is longer than the radius
What is Cephalic Index?
Used to determine the normality of the fetal head shape. CI= BPD/OFDx 100
With Oblique lie how would you describe where the fetal head is?
Using the quadrant of the uterus that contains the fetal head. Ex: RUQ, LUQ, RLQ, LLQ
When the LMP is unknown or the patient has irregular menstrual cycles, the estimated date of confinement (EDC) or due date is derived by other clinical parameters: (4)
Uterine size Doptone [auscultation of fetal heart tones] Ultrasound ovulation indicators
The ______________________________ cannot be included as part of the fluid measurement.
Uterine wall
a ___________ presentation the cranium is closest in proximity to the direction of the cervix.
Vertex
If the fetus is lying longitudinal or parallel to the maternal long axis what are the two positions that baby can be described in (head down, Head up)?
Vertex Breech
What is footling breech?
When the hips are extended and one (single footling) or both (double footling) feet are the presenting parts closest to the cervix
The adrenal is located __________ the kidney. The texture of the adrenal gland is _________ to that of the kidney
above similar
Measure the more _____________ leg, then image both to make sure there are two
anterior
The circle of Willis may be seen ___________ to the midbrain and appears as a triangular region.
anterior
The circle of Willis highly pulsatile as a result of the midline-positioned _____________ ____________ artery and lateral convergence of the __________ _________________ arteries.
anterior cerebral middle cerebral
Along the midline echo, the paired thalamus lies on either side and resembles a heart. The ______ of the heart-shaped thalamus points towards the _________
apex face
What should fetal heart demonstrate to be considered normal during a non-stress test?
at least 2 episodes of FHR greater than 15 bpm and at least 15 seconds duration in a 20 minutes period
When the umbilical cord is not twisted, what does that indicate?
baby has not been moving
to measure the foot, you measure from the ___________ to the ________.
big toe heel
Color doppler shows two umbilical arteries surrounding the ____________.
bladder
The fetal head is visualized at level of _____________ and ___________ when the fetus is in a vertex or cephalic presentation.
bladder LUS
The __________ of the choroid plexus marks the site at which the size of the ventricle may be assessed.
body (glomus)
The body is closest in proximity to the direction of the cervix in a ___________ presentation
breech
the cranium is directed toward the uterine fundus in a ________________ presentation
breech
The scanner should assess the following in the four-chamber view (3):
cardiac position proper situs axis
Moving the transducer in a more ____________ direction identifies the echogenic midline echo complex. This is the widest transverse diameter of the skull and is therefore the proper level at which to measure the ______
caudal BPD
The box-shaped _______________________ is observed in front of the thalamus
cavum septum pellucidum (CSP)
What echogenic structure is located within the lateral ventricles?
choroid plexus
By viewing the CSP, an anomaly known as _________________________________ may be excluded
complete agenesis of the corpus callosum
By placing the transducer in a __________ scanning plane, sectioning through the face reveals both *orbital rings*, *parietal* bones, *ethmoid* bones, *nasal septum*, *zygomatic* bone, *maxillae*, and *mandible*.
coronal
Increased nuchal translucency down entire spine indicates a ____________________.
cystic hygroma
The texture of the choroid plexus should be assessed to exclude the formation of _________.
cysts
Fetal lung tissue appears __________- than the liver as pregnancy progresses
denser
In skin defects, what 3 things may be seen?
dimple, bulge, or cyst in the skin
In general, two types of brain tissues are highly echogenic, the ______ and the ____ ______________ , which covers the inner and outer brain surfaces.
dura pia arachnoid
The fetal ______ may be defined in the second trimester as lateral protuberances emerging from the _________ bones.
ears parietal
Scans obtained in an anterior plane over the orbits demonstrate the __________ and, when directed posterior to this plane, the _________ _______
eyelids orbital lens
Measurements of cerebellar width allow assessment of _______ ______ and permit necessary follow-up in fetuses with ________ __________ and other anomalies of the cerebellum.
fetal age spinal defects
Lack of _____________ can result in open spinal defects
folic acid
The head may be safely turned or averted, allowing vaginal delivery with a ____________ presentation
frank breech
the presence of the CSP signifies normal development of the __________ ____________.
frontal midline
Two types of amniocentesis:
genetic lung maturity
Fetal ________ is often observed along the periphery of the skull and must NOT be included in the biparietal diameter measurement.
hair
The fluid-filled fetal lungs are observed as solid ________________ masses of tissue bordered medially by the heart, inferiorly by the diaphragm, and laterally by the ribcage.
homogenous
___________ can cause pleural effusion
hydrops
When doing an amnio with multiple sacs how do we differentiate sacs?
inject indigo carmine dye to make sure we sample separate sacs
The circle of echoes represents the center of the vertebral body and the posterior elements , which are ______________ or _______________
laminae pedicles
The apex of the fetal heart should point to the fetal ___________ side
left
In evaluating the cranium, the _______________ of the fetus is determined
long axis
brain tissue, a solid structure, may appear hypoechoic or cystic because of the _______ ______________ of the tissue. Brain tissue does not exhibit typical solid appearances because of the small size of the _______________ _______________. Echoes are not generated unless the reflectors are large enough to cause reflections. The _________ content of the fetal brain is high, also contributing to the cystic appearance of various brain structures.
low density reflective interfaces water
2 types of amniocentesis:
lung maturity genetic
What 3 things are routinely assessed to rule out lung mass?
lung size texture location
The fetal lie is described in relation to the ___________________.
maternal long axis
The ventricular cavity is represented sonographically as an echo-free space, filled with choroid plexus, housed between the ______________________ and the ____________________.
medial ventricular border lateral ventricular border
The tibia is __________ positioned and the fibula is _________ positioned
medially laterally
It is important to note the integrity of the skin surface because this ______________ is absent in fetuses with ______________________.
membrane open spina bifida
A transverse plane the spinal column appears as a closed circle, indicating closure of the _________________.
neural tube
Profile views of the face are useful in determining the relationship of the _______ to the ________, excluding _________ malformations. In this view, the contour of the frontal bone, nose, upper and lower lips, and chin may be visualized.
nose lips forehead
It is important to recognize the usual configuration of the cerebellum, because distortion may represent findings such as _____________ (known as "__________ _______"). The cerebellum may be small or displaced downward into the _______________
open spina bifida banana sign foramen magnum
Measurements of ________ width have been reported to aid in gestational age. What two measurements are there?
orbital Outer orbital diameter (OOD) Inner orbital diameter (IOB)
When scanning inferior to or below the cerebellar plane, the _______ may be visualized.
orbits
The cerebellum is located in back of the cerebral _____________ within the _______________.
peduncles posterior fossa
When evaluating the spine, it is imperative for the sonographer to align the transducer in a ____________________ axis to the spinal elements.
perpendicular
By rotating the transducer ________________, the long axis of the fetus should be observed in a transverse lie
perpendicularly
When the fetal lie is transverse, the sonographer typically reports: (2)
position of fetal head position of fetal spine
Scan baby in __________ position to view the spine the best
prone
This double line appearance of the spine is referred to as the _____________________ and is generated by echoes from the posterior and anterior laminae and spinal cord.
railway sign
The ___________, ______________, and ______________ are landmarks of the chest cavity
ribs scapulae clavicles
if the fetus is in a vertex presentation with the fetal spine toward the maternal right side, the ________ side of the fetus is down while the _______ side is up
right left
Facial morphology becomes more apparent in the ___________ trimester. What two things does face morphology visualization depend on?
second amniotic fluid position
What size should the nuchal fold not exceed?
should not exceed 6mm
In fetuses it is important to note the integrity of the skin surface around the spine because this membrane is absent in fetuses with open _______________
spina bifida
The oral cavity and tongue are frequently outlined during fetal ______________.
swallowing
what view is helpful in the diagnosis of craniofacial anomalies, such as cleft lip?
tangential
As the brain develops, structures change their sonographic appearances. Give an example of this:
the choroid plexus seem large early in pregnancy, but as the brain grows, these structures appear small in relationship to the entire brain
What is Menstrual age?
the gestational age of the fetus determined from the LMP
The radius is usually ________ than the ulna
thicker
Between the thalamic structures lies the cavity of the _______ ______________.
third ventricle
Between the thalamic structures lies the cavity of the______________
third ventricle
Although the fetus is unable to breathe air in utero, the lungs are important landmarks to visualize within the ___________ cavity. The lungs serve as lateral borders for the heart; therefore, they are helpful in assessing the relationship and position of the heart in the chest.
thoracic
The fetal heart is positioned _______________ in the chest.
transversely
The _________________ indicates female biological sex, while the ______________ indicates male biological sex
triple line sign turtle sign
In a coronal section the spine appears as ________ ____________ _________ extending from the cervical spine to the sacrum.
two curvilinear lines
Always show both ________ and _______ when imaging fetal upper extremities
ulna radius
After entering at the umbilicus, the ______________ courses cephalad and into the liver
umbilical vein
The _______________________ is represented sonographically as an echo-free space, filled with choroid plexus, housed between the medial ventricular border and lateral ventricular border
ventricular cavity
If the glomus appears to float or dangle within the cavity, measurements of _________________ are recommended to exclude ____________________
ventricular size ventriculomegaly
the body is directed toward the uterine fundus in a _____________ presentation
vertex (cephalic)
