Imaging Techniques & Protocols Flashcards

Which transducer frequency range is most appropriate for fetal echocardiography in a patient with a BMI >35?

Answer: 2–4 MHz

Lower frequencies (2–4 MHz) provide better tissue penetration in obese patients despite reduced resolution.

The ISUOG guideline recommends obtaining a fetal echocardiogram at what gestational age for optimal image quality?

Answer: 18–22 weeks

18–22 weeks is the standard window recommended by ISUOG for detailed fetal cardiac evaluation.

When performing fetal echocardiography, which view is obtained by rotating the transducer 90° from the four-chamber view toward the fetal left shoulder?

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.

In color Doppler imaging during fetal echocardiography, aliasing artifacts indicate that flow velocity exceeds which parameter?

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.

Which M-mode measurement is used to calculate the cardiothoracic ratio in fetal echocardiography?

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.

What is the primary advantage of spatiotemporal image correlation (STIC) in fetal echocardiography?

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.

During spectral Doppler assessment of fetal cardiac valves, the sample volume should be placed how relative to the valve annulus?

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.