Midtrimester scan

Question 1

How many major anomalies are identified before 24 weeks?

Answer 1

55%

Question 2

Prenatal screening examination includes (5)

Answer 2

cardiac activity
fetal number (and chronicity)
fetal age/size
basic fetal anatomy
placental appearance and location
AFI

Question 3

Timing of mid trimester fetal ultrasound

Answer 3

18-24 weeks

Question 4

Who should perform mid trimester screening scans

Answer 4

• trained in the use of diagnostic ultrasonography and safety issues
• regularly perform fetal ultrasound scans
• participate in CME
• established referral patterns
• routine QA and control measures

Question 5

Basic requirements for equipment to do routine ultrasound screening

Answer 5

• real tie, grey-scale ultrasound capabilities
• transabdominal transducers (3-5mHz range)
• adjustable acoustic power output controls with output display standards
• freeze frame capabilities
• electronic calibers
• capacity to print/store images
• regualar maintenance and servicing

Question 6

Anatomy for biparietal diameter

Answer 6

• Cross-sectional view of the fetal head at the level of the thalami
• Ideal angle is 90deg to midline
• symmetrical appearance of both hemisphere
• continuous midline echo broken by cave septic and thalamus
• no cerebellum

Question 7

Anatomy of abdominal circumference

Answer 7

• transverse section of the deal abdomen as circular as possible
• umbilical vein at the level of the portal sinus
• stomach bubble visualised
• kidneys not visible

Question 8

Evaluation of multiple pregnancies

Answer 8

• visualisation of the placental cord insertions
• distinguishing features (gender, unique markers, position in uterus)
• determination of chorionicity ideally before 15w

Question 9

Four areas of the fetal skull that should be evaluated

Answer 9

• Size
• Shape
• Integrity
• Density

Question 10

Which brain structures should be evaluated

Answer 10

• Intact cranium
• Normal head shape
• lateral ventricles
• cavum septi pellucidi
• Normal choroid plexus
• midline falx
• thalami
• cerebrellum
• cisterna magna
• normal nuchal fold

Question 11

Minimum evaluation of the face

Answer 11

• Upper lip for cleft lip anomalies
• If technically feasible - midsagittal facial profile, orbits & bulbs, nasal bone and nostrils

Question 12

Examples of conotruncal anomalies

Answer 12

• tetralogy of fallot
• transposition of the great arteries
• double outlet right ventricles
• trunks arteriosus

Question 13

What is the most sensitive of finding for placenta accreta spectrum

Answer 13

Multiple irregular placental lacunae that show arterial or mixed flow

Question 14

Chest/Heart anatomy

Answer 14

• Normal appearing shape/size
• Heart activity present
• Four chamber view of heart in normal position
• Aortic and pulmonary outflow tracts
• No evidence of diaphragmatic hernia

Question 15

Abdominal anatomy

Answer 15

Stomach in normal position
Bowel not dilated
Both kidneys present
Cord insertion site