ARDMS Echo Doppler Echocardiography 1 — Questions and Answers
Question 1: Which Doppler modality provides the highest velocity resolution and is best for measuring high-velocity jets?
- Pulsed-wave Doppler
- Continuous-wave Doppler (Correct answer)
- Color flow Doppler
- Tissue Doppler imaging
Correct answer: Continuous-wave Doppler
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:
- The pulse repetition frequency
- Half the pulse repetition frequency (Nyquist limit) (Correct answer)
- The carrier frequency
- The frame rate
Correct answer: Half the pulse repetition frequency (Nyquist limit)
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?
- 90 degrees
- 60 degrees
- 45 degrees
- 0 degrees (parallel alignment) (Correct answer)
Correct answer: 0 degrees (parallel alignment)
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?
- Peak LV systolic pressure
- Stroke distance (distance blood travels per beat) (Correct answer)
- Mean aortic gradient
- LVOT cross-sectional area
Correct answer: Stroke distance (distance blood travels per beat)
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?
- Red blood cells in cardiac chambers
- Myocardium and cardiac walls (Correct answer)
- Pulmonary venous flow
- Aortic root motion
Correct answer: Myocardium and cardiac walls
TDI uses low-gain, high-pass filtering to measure myocardial wall velocities rather than blood flow velocities.
Question 6: Which color flow Doppler finding is characteristic of mitral regurgitation?
- Diastolic jet from LA into LV
- Systolic mosaic jet from LV into LA (Correct answer)
- Diastolic jet from aorta into LV
- Systolic jet from RV into PA
Correct answer: Systolic mosaic jet from LV into LA
Mitral regurgitation appears as a systolic color flow jet directed from the LV back into the left atrium.
ARDMS Echo Doppler Echocardiography 1
Which Doppler modality provides the highest velocity resolution and is best for measuring high-velocity jets?