ARDMS Echo Doppler Principles and Applications

Question 1

What is the Nyquist limit in pulsed wave Doppler echocardiography?

Accepted Answer

Half the pulse repetition frequency

Answer

The pulse repetition frequency

Answer

Twice the pulse repetition frequency

Answer

The transducer frequency

Question 2

Which Doppler modality is best suited for measuring high-velocity jets such as severe aortic stenosis?

Accepted Answer

Continuous wave Doppler

Answer

Pulsed wave Doppler

Answer

Color flow Doppler

Answer

Power Doppler

Question 3

What effect does increasing the angle of insonation (θ) beyond 20° have on Doppler velocity measurements?

Accepted Answer

Underestimates true velocity

Answer

Overestimates true velocity

Answer

No effect on velocity

Answer

Improves spatial resolution

Question 4

In color flow Doppler, what does aliasing (color reversal to the opposite color) indicate?

Accepted Answer

Velocities exceeding the Nyquist limit

Answer

Turbulent flow only

Answer

Backscatter artifact

Answer

Gain set too low

Question 5

Which Doppler technique allows simultaneous visualization of flow direction and velocity across a 2D image?

Accepted Answer

Color flow Doppler

Answer

Pulsed wave Doppler

Answer

Continuous wave Doppler

Answer

Tissue Doppler imaging

Question 6

What is the primary advantage of tissue Doppler imaging (TDI) over conventional Doppler in diastolic assessment?

Accepted Answer

It measures myocardial wall motion velocity and is less preload dependent

Answer

It measures blood flow velocity more accurately

Answer

It is not affected by angle of insonation

Answer

It detects higher velocities without aliasing