Practice exam

Question 1

What is gastrulation?

Answer 1

The formation of the trilaminar disc from the bilaminar disc.
three primary germ cell layers: ectoderm, mesoderm, and endoderm

Question 2

What is neurulation?

Answer 2

The formation of the neural plate and its closure to form the neural tube
process begins in the fifth week in the thoracic region and extends caudally and cranially, resulting in complete closure by the end of the sixth week (day 42).
Failure of closure of the neural tube results in neural tube defects.

Question 3

What is the FMF angle a marker for in the first trimester?

Answer 3

aneuploidy

Question 4

What is the normal FMF angle?

Answer 4

< 85 degrees

Question 5

List two ways of distinguishing an interstitial ectopic pregnancy from a high
implantation of a normal pregnancy

Answer 5

Interstitial line sign

Double decidual sign

Question 6

True or False- Cardiac Arrhythmia in first trimester is a benign finding?

Answer 6

True

Question 7

True or False- Low level echoes in the yolk sac in first trimester is a benign finding?

Answer 7

True

Question 8

List 2 abnormalities that are seen in Triploidy

Answer 8

Cystic placenta
growth-retarded fetus
degeneration of fetal parts
renal, brain, heart abnormalities

Question 9

The author of the Twin twin transfusion staging is

Answer 9

Quintero

Question 10

List 4 second trimester markers that alter risk the patient’s risk of Down Syndrome in
an otherwise, low risk patient.

Answer 10

Nuchal fold >6mm
Absent or hypoplastic nose
Cardiac defect
Short femur and humerus
Echogenic bowel
Hypoplasia of the fifth digit
Omphalocele

Question 11

Congenital cataracts are associated with

Answer 11

Aneuploidy (trisomy 21)

Question 12

Two differential diagnoses for a branching LVOT are

Answer 12

Double aortic arch
Transposition of the great arteries (because pulmonary artery is coming out of the left ventricle and branching as it usually does)
Aberrant left common carotid
Aberrant left subclavian

Question 13

Define the following terms relating them to ultrasound:

(a) Threatened abortion

Answer 13

When there is bleeding in the subchorionic space that is not significant enough to cause embryonic demise.
The cervix is closed.

Question 14

Define the following terms relating them to ultrasound:

(b) Incomplete abortion

Answer 14

When there is evidence of RPOC
Hyperaemic, echogenic.
Can have severe bleeding that leads to hypovolemic shock and death
When bleeding continues one week after a suspected complete abortion then it is complete

Question 15

Define the following terms relating them to ultrasound:

(c) Inevitable abortion

Answer 15

Once the cervix is open it becomes inevitable
Bleeding usually increases
Strong contractions may follow

Question 16

Define the following terms relating them to ultrasound:

(d) Missed abortion

Answer 16

the embryo dies but the gestational sac is retained
uterus is smaller than expected for the gestation
eventually expelled spontaneously, but sometimes not for many weeks.
A suction curettage is therefore often performed

Question 17

What criteria do you use to establish pregnancy failure in first trimester according to ASUM
policy?

Answer 17

1. CRL >7mm with no heartbeat after 30s
2. MSD >25mm with no fetal pole

Initial scan showed foetal pole <7mm with no cardiac activity and a repeat scan in 7 or more days also shows no cardiac activity
Initial scan showed an MSD >12mm with no embryo and a repeat scan in 7 or more days does not show interval development of a yolk sac or an embryo with cardiac activity
Initial scan showed an MSD <12mm with no embryo and a repeat scan in 14 or more days shows no visible yolk sac or cardiac activity and the MSD has not doubled
Yolk sac is visible on the initial scan and there is no embryo with a heart beat after 11 days
Absence of cardiac activity which was present on an earlier scan.

Question 18

Compare and contrast the appearances of the endometrium when there is an early
intrauterine pregnancy (pre-appearance of a gestational sac) to the endometrium when there
is an ectopic pregnancy.

Answer 18

IUP
The earliest sonographic sign of an IUP is a focal echogenic zone of decidual thickening at the site of implantation at about 3½ to 4 weeks of gestational age. This sign is nonspecific and of limited diagnostic value.

Ectopic

• no specific endometrial appearance or thickness to indicate an ectopic
• Most common appearance during ectopic is normal or increased echogenicity
• Pseudogestational sacs are endometrial fluid collections surrounded by echogenic endometrium form a prominent decidual reaction

Question 19

Draw and describe the most important biometrical measurement done in weeks 7-13 of
embryonic life.

Answer 19

CRL - crown rump length
The meausrement goes from the crown to the rump
the fetus should be horizontal across the screen and not hyperflexion or extension
Zoomed to fill the screen
Parameters adjusted for crispy edges
3 x measurements at least, from different angles. Take the mean.

Question 20

Nuchal translucency is used to calculate a risk of Down syndrome in first trimester.
What other ULTRASOUND parameters can be used in first trimester to assist this
calculation.
Describe how these are used and in what circumstances might they be beneficial.

Answer 20

Tricuspid regurg - Abnormalities with the great vessels

Ductus venosus - A-wave anomalies are seen in 80% of fetuses with trisomy 21

Nasal bone - nasal bone abnormalities are significantly more common in trisomy 21 fetuses than in euploid fetuses

In the circumstance where the patient is not having combined screening.
Detection rates of Down syndrome of 80%, 87%, and 94% are reported when using one, two, or three additional ultrasound markers while maintaining the FPR at 3%
beneficial because they increase the detection rate

Question 21

Draw the correct anatomical plane for the measurement of the nuchal fold noting the
important relationships and anatomical structures.

Answer 21

Cerebellar plane
Cavum septum pellucidum
Thalami
Cerebellar hemispheres and vermis
Cisterna magna
Falx
Anterior horns of the lateral ventricles

Question 22

Define and list the sonographic appearances of:

(a) Macroglossia

Answer 22

Large tongue
Protrusion of the tongue between the lips
will remain out even during swallowing movements
May be polyhydramnios due to swallowing problems
best visualised on midsagittal plane

Question 23

Define and list the sonographic appearances of:

(b) Aqueductal stenosis

Answer 23

Overt ventriculomegaly
Dilated third ventricle
Normal 4th ventricle
Post fossa also normal
Associated parenchymal thinning

Question 24

Define and list the sonographic appearances of:

(c) Potters syndrome

Answer 24

A mix of findings as a result of prolonged oligohydramnios due to bilateral renal agenesis
Pulmonary hypoplasia
Oligohydramnios
Wrinkled skin
Low set ears
extremity deformities
retrognathia
renal agenesis
hypotelorism
FGR

Question 25

the sonographic appearances and significance of gastroschisis

Answer 25

Protrusion of the bowel from the anterior abdominal wall to the right of the umbilical cord insertion Cauliflower appearance No covering by membranes Gastroschisis is not associated with aneuploidy Associated with teen pregnancy and alcohol and substance abuse

Question 26

the sonographic appearances and significance of an omphalocele.

Answer 26

Herniation of the bowel and other abdominal structures into the base of the umbilical cord. Covered by a thin membrane consisting of peritoneum and amnion cord inserts into the sac itself If just bowel more likely to be associated with aneuploidy Smooth walled potential displaced stomach Contents may include bowel or liver

Question 27

What is tetralogy of fallot

Answer 27

VSD Overriding aorta Right ventricular hypertrophy (rarely seen in utero Pulmonary artery (RVOT) stenosis

Question 28

What views should you use to assess TOF?

Answer 28

4ch - for VSD RVOT LVOT - Right displacement of the aorta, VSD, overriding aorta 3VV - aorta may be larger than pulmonary artery due to stenosis/atresia

Question 29

What views should you use to assess TOF?

Answer 29

4ch - for VSD RVOT LVOT - Right displacement of the aorta, VSD, overriding aorta 3VV - aorta may be larger than pulmonary artery due to stenosis/atresia

Question 30

How do you use LVOT view to assess TOF?

Answer 30

Right displacement of the aorta, VSD, overriding aorta. Identifying the absence of a pulmonary artery branching off the LVOT helps to differentiate from truncus arteriosus.

Question 31

A patient presents for an 18-20 morphology scan and there is significant maternal adipose tissue between the transducer and the fetus. List modifications to your ultrasound system set-up that will improve the quality of your imaging. *NB Note the change and the impact of the change on the image

Answer 31

Lower frequency transducer Better resolution at greater depth Lower frequency harmonics Improves contrast resolution dynamic range (increase and decrease) - decrease your dynamic range which will increase your contrast resolution implementation of compound imaging in the setting is essential reduces image artifacts and thereby improves tissue-plane definition

Question 32

Define oligohydramnios

Answer 32

Abnormally low volume of amniotic fluid. Defined as deepest vertical pocket <2cm and at least 1 cm wide or AFI <5.

Question 33

discuss the significance oligohydramnios of this finding in second trimester

Answer 33

``` Pulmonary hypoplasia Suggests severe renal malformation IUGR Can indicate premature rupture of membranes Chromosomal disorders Presumed placental dysfunction abnormal swallowing ```

Question 34

Describe in detail, your examination of the fetus for spina bifida at the head and sonographic appearances that you may see.

Answer 34

Head Anencephaly Exancephaly Chiari II malformation - Classic sonographic sign is the deformation of the cerebellar shape ‘banana sign’ and the non-visualisation of the cisterna magna Most common manifestation is the obliteration of the cisterna magna Concave deformity of the foetal frontal bones cause the lemon sign Nonvisualisation of the intracranial translucency (4th ventricle)

Question 35

Describe in detail, your examination of the fetus for spina bifida at the lumbar spine and sonographic appearances that you may see.

Answer 35

Laminae fail to converge towards the midline Increased interpedicular distance Pedicles may diverge away from the midline instead of being parallel Absent overlying skin or subcutaneous tissue

Question 36

Describe your Spectral Doppler assessment of the Umbilical Artery in third trimester. Include in this discussion: (a) Normal spectral waveforms

Answer 36

To produce an accurate measurement UA-PI must be measured from a free-floating portion of cord with an angle of insonation as close to 0 degrees as possible never exceeding 30 degrees observations based on at least 3 consecutive waveforms Flow in the umbilical artery is normally low resistance with an S/D ratio of less than 3.5 up to 28 weeks’ gestation less than 3.0 thereafter

Question 37

Describe your Spectral Doppler assessment of the Umbilical Artery in third trimester. Include in this discussion: (b) Abnormal spectral waveforms

Answer 37

As placental insufficiency worsens there is higher placental resistance leading to an increased PI and absent or reversed end-diastolic flow

Question 38

Describe your Spectral Doppler assessment of the Umbilical Artery in third trimester. Include in this discussion: (c) The reasons that the waveform changes occur.

Answer 38

Bad measurement Breathing Fetal movement Abnormal UA correlates with placental dysfunction and foetal compromise Often provides early warning of foetal distress

Question 39

Describe the method of measuring fetal weight in the third trimester

Answer 39

AC is the most important measurement HC BPD FL

Question 40

Briefly describe the key components of a biophysical profile.

Answer 40

Breathing - 30 seconds continuous Tone - 1 episode of extension and flexion Movement - 3 discrete body and limb movements AFI - single pocket 1cm across and 2 cm deep at least

Question 41

Briefly discuss the recommendations which | ensure ultrasound systems are safe.

Answer 41

Heating TI ≥ 1 must be indicated on the scanner display screen Only perform a scan when medically indicated The examination should be undertaken in the minimum time with the lowest possible power consistent with a diagnostically meaningful image The sonographer should not rest the transducer on the patient when on, but not actually scanning Be particularly careful about dose when using spectral Doppler (power high), and when scanning bone (thermal effects)

Question 42

Briefly discuss the thermal biological effects of ultrasound

Answer 42

central nervous system (CNS) is most at risk neural tube (anencephaly, microencephaly) and the eyes (microphthalmia, cataract) Associated with CNS defects are functional and behavioral problems Other organ defects secondary to hyperthermia include: defects of craniofacial development (e.g., clefts) anomalies of the axial and appendicular skeleton the body wall teeth heart Gestational age is critical when considering heat dispersion In early human pregnancy, less than 6 weeks, the minimal fetal perfusion may reduce heat dispersion

Question 43

Chorionic Villi Sampling

Answer 43

10 -12.6 weeks only diagnostic higher miscarriage risk ~1% main indication is karyotyping

Question 44

Amniocentesis

Answer 44

15 - 20 weeks can be therapeutic as well as diagnostic Lower miscarriage risk ~0.5% main indication is karyotyping

Question 45

differences between the fetal and post | natal circulatory system

Answer 45

Fetal shunts Ductus venosus Foramen ovale Ductus arteriosis Oxygenated blood -> placenta -> umbilical vein -> Ductus venosus -> IVC -> right atrium -> left atrium -> Aorta -> umbilical arteries

Question 46

List three ultrasound system B-mode changes that may help you to differentiate between dropout and an interventricular septal defect.

Answer 46

``` • using multiple scanning planes to view the regions, preferably with the scan plane perpendicular to the septum; and - increase gain - Use lower frequency transducer - decrease dynamic range ?using colour flow imaging. ?power imaging ```

Question 47

discuss the first trimester determination of chorionicity and amnionicity.

Answer 47

From 8 weeks, it is possible to visualise the amnion, allowing for the determination of amnionicity Prior to 8 weeks, the number of yolk sacs can also be used to determine amnionicity Dichorionic: Easily seen at 6 weeks with two separate chorions, within each sac there will be a yolk sac Twin peak sign/lambda sign Membrane thickness >2mm Monochorionic: Single chorion No amniotic membrane seen until approximately 8 weeks Two yolk sacs means its probably diamniotic Single yolk sac with 2 foetuses = probably monoamniotic Repeat scan at 9 weeks