fetal Development And Clinnical Imaging

Question 1

What is the Chorion?

Answer 1

The chorion is formed from mesoderm and trophoblasts and becomes the wall of thee chorionic cavity.

Question 2

What is the Chorionic cavity?

Answer 2

It’s the anechoic fluid collection in which the embryo, amnion and yolk sac are suspended and grow.

Known as the gestational sac.

Question 3

What is an Anembryonic pregnancy ?

Answer 3

Pregnancy in which a gestational sack grows but an embryo fails to develop

It’s the earliest sign that something has gone wrong in the pregnancy .

Question 4

How many placentas do Monochorionic twins have?

Answer 4

One placenta

Question 5

How many placentas do Dichorionic twins have?

Answer 5

Two placentas

Question 6

What does the The Nuchal test / combined screening at 11-13 weeks involve?

Answer 6

• Maternal age is a risk factor
• Maternal blood sample, for the measurement of the placenta products of free B-hCG and PAPP-A
• US at 11-13 weeks to look at/ measure / examine:
  ~ collection of fluid behind the fetal neck (Nu Hal translucency)
  ~ Fetal nose and palate
  ~ heart rate of fetus
  ~ flow of blood across the tricuspid valve of fetal heart and ductus venosus

Question 7

What does B- HCG stand for ?

Answer 7

Beta - human chorionic gonadotropin

Question 8

What does PAPP-A stand for?

Answer 8

Pregnancy associated plasma protein - A

Question 9

Blood tests also can determine the risk for which syndromes?

Answer 9

Trisomy 21 (Downs syndrome)
Trisomy 18 (Edward’s syndrome)
Trisomy 13 (Patau syndrome)

The blood test is used with other risk factors eg: maternal age

Question 10

Which results indicate Risks for Chromosomal abnormalities ?

Answer 10

1. Increased in nuchal translucency as measured in mm
2. Low PAPP-A levels
3. High hCG levels

Question 11

What does FASP stand for?

Answer 11

Fetal anomaly screening program

Question 12

At how many weeks gestation is a FASP Ultrasound is performed ?

Answer 12

Between 18 weeks and 20 weeks and 6 days

Question 13

What are the 11 conditions screened for at 20 week scan?

Answer 13

1. Anencephaly
2. Open Spina bifida
3. Cleft lip
4. Congenital heart disease
5. Diaphragmatic hernia
6. Gastroschisis
7. Exophalos
8. Bilateral renal agenesis
9. Lethal skeletal dysplasia
10. Edward’s syndrome (T 18)
11. Patau syndrome (T13)

Question 14

What are the 4 common Congenital heart diseases?

Answer 14

TGA - transposition of the great arteries
AVSD - Atrioventricular septal defect
TOF - Tetralogy of Fallot
HLHS - Hypoplastic left heart syndrome

Question 15

What is the Neural plate?
How does the neural plate form into the neural tube?

Answer 15

The neural plate is a disc shaped cluster of cells that clump together about two weeks after conception

The neural plate rolls into a tube called the neural tube at three weeks after conception, and this new tube is the beginning of the central nervous system

The front of the neural tube will inflate to form the brain and the portion of the tube behind the brain forms the spinal cord .

Question 16

What are Neural tube defects and how common are they?

Answer 16

Common - 1/1000 births

A variety of defects most result from a lack of closure of the neural tube.

Question 17

What is Anencephaly?

Answer 17

Severe congenital condition in which a large part of the skull is absent along with the cerebral hemispheres of the brain,

Early appearances involve absence of the skull with protruding brain.

As pregnancy progresses, the amniotic fluid degrades the brain .
75% will be still born

Question 18

What is Associated Talipes?

Answer 18

“Tethering” of the spinal cord

May have difficulty walking, bladder and bowel control

Question 19

What are Risk factors for cleft lip and palate ?

Answer 19

• genetics
• environmental agents such as second hand exposure to smoke
• Medications such as phenytoin, sodium valproate, topiramate and methotrexate
• smoking and tobacco
• folate deficiency
• maternal obesity
• Diabetes - T1 or T2 Moore risk than gestational

Question 20

What are Cleft lip and palate and how are they detected?

Answer 20

Can be syndromic
Detected using coronal views on USS - 30% still missed
Babies need assisted feeding

Question 21

What is Gastroschisis?

Answer 21

An abdominal wall defect where the intestines develop on the outside and are completely open to air when the baby is born.

Question 22

What is Exomphalos / Omphelcele ?

Answer 22

An abdominal wall defect where the intestines are outside the body but remain covered by a membrane

Question 23

What is Ductus arteriosus ?

Answer 23

Duct between the aorta and pulmonary artery
Open in uterus but closes shortly after birth

Babies with TGA its their only hope of survival

Question 24

What is a Congenital diaphragmatic hernia?
What are the associated risks?

Answer 24

Organs take up space in the chest ——-> This prevents the lungs from growing properly

Pulmonary hypertension

Will be difficult for lungs to expand and get enough O2 when the baby is born.
They can be repaired

Question 25

What is Bilateral renal agenesis?

Answer 25

• no development of kidneys
• Little and amniotic fluid
• Lungs cannot develop properly
• Absent stomach and bladder bubble
• No kidneys

Question 26

How is placenta praevia managed?

Answer 26

Discovery at 20 week scan

Repeat scan @ 32 weeks

If still low consult obstetrics to discuss delivery and repeat scan at 36 weeks

Question 27

What other Normal variants are visible on us ?

Answer 27

Choroid plexus cysts
Echo genie foci in the heart
2 vessels in the umbilical cord

Question 28

What Isolated findings require further assessment ?

Answer 28

Nuchal fold > or equal to 6mm
Ventriculomegaly - atrium > or equal to 10mm
Echo genie bowel = bone density
Renal pelvis dilitation > 7mm
Fetal biome try measurement <5th centile