FE Imaging Techniques & Protocols 2 — Questions and Answers
Question 1: Which transducer frequency range is most appropriate for fetal echocardiography in a patient with a BMI >35?
- 2–4 MHz (Correct answer)
- 5–8 MHz
- 8–12 MHz
- 12–15 MHz
Correct answer: 2–4 MHz
Lower frequencies (2–4 MHz) provide better tissue penetration in obese patients despite reduced resolution.
Question 2: The ISUOG guideline recommends obtaining a fetal echocardiogram at what gestational age for optimal image quality?
- 14–16 weeks
- 18–22 weeks (Correct answer)
- 24–28 weeks
- 30–34 weeks
Correct answer: 18–22 weeks
18–22 weeks is the standard window recommended by ISUOG for detailed fetal cardiac evaluation.
Question 3: When performing fetal echocardiography, which view is obtained by rotating the transducer 90° from the four-chamber view toward the fetal left shoulder?
- Short-axis view
- Three-vessel view
- Long-axis left ventricular outflow tract view (Correct answer)
- Ductal arch view
Correct answer: Long-axis left ventricular outflow tract view
Rotating 90° from the four-chamber view toward the fetal left shoulder yields the long-axis LVOT view showing the aortic root.
Question 4: In color Doppler imaging during fetal echocardiography, aliasing artifacts indicate that flow velocity exceeds which parameter?
- Nyquist limit (Correct answer)
- Pulse repetition frequency
- Frame rate
- Dynamic range
Correct answer: Nyquist limit
Aliasing occurs when detected velocities exceed the Nyquist limit, causing color wrap-around from one end of the scale to the other.
Question 5: Which M-mode measurement is used to calculate the cardiothoracic ratio in fetal echocardiography?
- Ventricular wall thickness at end-diastole
- Maximum cardiac diameter compared to thoracic diameter at the same level (Correct answer)
- Aortic root diameter at systole
- Right atrial area at end-diastole
Correct answer: Maximum cardiac diameter compared to thoracic diameter at the same level
The cardiothoracic ratio is obtained by dividing the maximal cardiac diameter by the thoracic diameter measured in the same transverse plane.
Question 6: What is the primary advantage of spatiotemporal image correlation (STIC) in fetal echocardiography?
- Real-time 2D scanning with higher frame rates
- Acquisition of a 4D volume dataset allowing off-line multiplanar reconstruction (Correct answer)
- Elimination of acoustic shadowing from ribs
- Measurement of myocardial strain
Correct answer: Acquisition of a 4D volume dataset allowing off-line multiplanar reconstruction
STIC acquires a volume sweep synchronized to the cardiac cycle, enabling off-line reconstruction of any imaging plane without re-scanning.
Question 7: During spectral Doppler assessment of fetal cardiac valves, the sample volume should be placed how relative to the valve annulus?
- 2–3 mm upstream of the valve
- Directly at the valve annulus
- 1–2 mm downstream of the valve leaflets (Correct answer)
- 5–10 mm downstream of the valve
Correct answer: 1–2 mm downstream of the valve leaflets
Placing the sample volume 1–2 mm downstream of the leaflets captures the jet after valve opening while minimizing contamination from adjacent structures.
FE Imaging Techniques & Protocols 2
Which transducer frequency range is most appropriate for fetal echocardiography in a patient with a BMI >35?