Imaging Techniques & Protocols Flashcards

What is the primary purpose of using a high frame rate (>100 fps) in fetal echocardiography?

Answer: To accurately capture rapid cardiac events such as valve motion in a high-heart-rate fetus

High frame rates are essential for capturing fast-moving structures accurately in the fetal heart, which beats at 120–160 bpm.

During fetal echocardiography, which maneuver helps optimally align the Doppler beam with aortic outflow when the fetus is in a lateral position?

Answer: Using the apical five-chamber view via a lateral acoustic window

When the fetal spine is lateral, an apical five-chamber view from the appropriate maternal flank provides near-parallel alignment of the Doppler beam with the LVOT.

The myocardial performance index (Tei index) in fetal echocardiography is calculated as:

Answer: (IVCT + IVRT) / Ejection time

The Tei index equals (IVCT + IVRT) divided by ejection time and provides a combined measure of systolic and diastolic ventricular function.

Which imaging modality is recommended as an adjunct to 2D fetal echocardiography for evaluating conotruncal anomalies when imaging conditions are suboptimal?

Answer: 3D/4D STIC with color flow mapping

3D/4D STIC with color flow mapping enables off-line multiplanar reconstruction of outflow tracts and great vessel relationships when 2D views are limited.

When evaluating pulmonary venous return in fetal echocardiography, which view most reliably demonstrates all four pulmonary veins entering the left atrium?

Answer: Posterior four-chamber view with slight posterior tilt

A slight posterior tilt from the standard four-chamber view opens the posterior left atrium and reveals the four pulmonary vein ostia.

Which of the following represents a contraindication to performing a fetal echocardiogram via the transvaginal route?

Answer: Placenta previa with active bleeding

Placenta previa with active bleeding is a contraindication to transvaginal scanning due to the risk of precipitating or worsening hemorrhage.

In spectral Doppler evaluation of the fetal ductus arteriosus, a pulsatility index (PI) below which threshold raises concern for premature constriction?

Answer: PI < 1.9

A ductal PI below 1.9 is the accepted threshold suggesting premature constriction of the ductus arteriosus, particularly after NSAID exposure.