FE FE Doppler Assessment 1 — Questions and Answers
Question 1: Which Doppler mode provides quantitative velocity measurements essential for fetal cardiac assessment?
- Color Doppler
- Power Doppler
- Pulsed-wave Doppler (Correct answer)
- B-flow imaging
Correct answer: Pulsed-wave Doppler
Pulsed-wave Doppler provides quantitative velocity measurements at a specific sample volume location, essential for fetal cardiac hemodynamic assessment.
Question 2: The Doppler angle of insonation should ideally be less than how many degrees for accurate velocity measurement?
- 15 degrees
- 30 degrees
- 45 degrees
- 60 degrees (Correct answer)
Correct answer: 60 degrees
A Doppler insonation angle less than 60 degrees is required for acceptable velocity accuracy, with angles below 20 degrees being ideal.
Question 3: Which Doppler waveform parameter reflects downstream vascular resistance?
- Peak systolic velocity
- End-diastolic velocity
- Resistance index (RI) (Correct answer)
- Acceleration time
Correct answer: Resistance index (RI)
The resistance index (RI = [peak systolic – end diastolic] / peak systolic) reflects downstream vascular resistance independent of absolute velocity.
Question 4: In which fetal vessel is Doppler assessment used to predict the risk of fetal chromosomal aneurysm in the first trimester?
- Middle cerebral artery
- Umbilical artery
- Ductus venosus (Correct answer)
- Umbilical vein
Correct answer: Ductus venosus
Abnormal ductus venosus Doppler (absent or reversed a-wave) in the first trimester is associated with increased risk of chromosomal abnormalities and cardiac defects.
Question 5: Color Doppler aliasing in fetal echocardiography indicates:
- Absent flow
- Flow velocity exceeding the Nyquist limit (Correct answer)
- Turbulent retrograde flow only
- Incorrect gain setting
Correct answer: Flow velocity exceeding the Nyquist limit
Color Doppler aliasing occurs when flow velocity exceeds the Nyquist limit of the pulse repetition frequency, causing color wrapping.
Question 6: Which Doppler finding is characteristic of pulmonary stenosis in the fetus?
- Decreased pulmonary artery velocity
- Increased pulmonary artery peak velocity with turbulence (Correct answer)
- Reversed pulmonary artery flow
- Normal pulmonary artery PI with color turbulence
Correct answer: Increased pulmonary artery peak velocity with turbulence
Pulmonary stenosis produces a high-velocity, turbulent jet across the pulmonary valve with elevated peak systolic velocity on pulsed-wave Doppler.
FE FE Doppler Assessment 1
Which Doppler mode provides quantitative velocity measurements essential for fetal cardiac assessment?