ARDMS Echo Doppler Echocardiography

Question 1

Which Doppler modality provides the highest velocity resolution and is best for measuring high-velocity jets?

Accepted Answer

Continuous-wave Doppler

Answer

Continuous-wave Doppler has no aliasing limit and can measure high-velocity jets such as severe aortic stenosis or regurgitation.

Question 2

Aliasing on pulsed-wave Doppler occurs when the measured velocity exceeds:

Accepted Answer

Half the pulse repetition frequency (Nyquist limit)

Answer

Aliasing occurs when blood velocity exceeds the Nyquist limit (½ PRF), causing the signal to wrap around the baseline.

Question 3

In the Doppler equation, which angle between the ultrasound beam and blood flow direction yields the most accurate velocity measurement?

Accepted Answer

0 degrees (parallel alignment)

Answer

At 0 degrees (parallel alignment), cos θ = 1, providing the most accurate velocity measurement with no angular error.

Question 4

What does the velocity-time integral (VTI) of the LVOT represent?

Accepted Answer

Stroke distance (distance blood travels per beat)

Answer

LVOT VTI represents the stroke distance — the column of blood ejected per heartbeat — and when multiplied by LVOT CSA gives stroke volume.

Question 5

Tissue Doppler imaging (TDI) measures velocities of which structure?

Accepted Answer

Myocardium and cardiac walls

Answer

TDI uses low-gain, high-pass filtering to measure myocardial wall velocities rather than blood flow velocities.

ARDMS Echo - American Registry for Diagnostic Medical Sonography Echocardiography Practice Test