ARDMS SPI Spectral Doppler Waveform Analysis 3

Question 1

Increasing the sample volume (gate) size in spectral Doppler will most likely:

Accepted Answer

Include more of the vessel lumen and potentially increase spectral broadening

Answer

Reduce aliasing by increasing the Nyquist limit

Answer

Improve angle correction accuracy

Answer

Decrease wall filter artifact near the baseline

Question 2

The systolic-to-diastolic (S/D) ratio used in obstetric Doppler is calculated as:

Accepted Answer

PSV / EDV

Answer

(PSV - EDV) / PSV

Answer

(PSV - EDV) / TAMV

Answer

EDV / PSV

Question 3

When PRF is increased to correct aliasing, which undesirable consequence may occur?

Accepted Answer

Range ambiguity — inability to unambiguously sample deep vessels

Answer

Improved sensitivity to low-velocity flow near the baseline

Answer

Increased wall thump artifact at the baseline

Answer

Decreased temporal resolution of the waveform

Question 4

Baseline shifting in spectral Doppler is primarily used to:

Accepted Answer

Reposition the zero-velocity line to allocate more display range to unidirectional flow

Answer

Increase the maximum detectable velocity by doubling the Nyquist limit

Answer

Correct for insonation angle errors

Answer

Reduce spectral broadening in turbulent flow

Question 5

Compared to pulsed-wave (PW) Doppler, which statement about continuous-wave (CW) Doppler is TRUE?

Accepted Answer

CW has no Nyquist limit and can measure very high velocities without aliasing

Answer

CW uses a range gate to precisely localize the sample volume

Answer

CW cannot measure high velocities without aliasing

Answer

CW provides superior depth resolution compared to PW

Question 6

A spectral Doppler waveform displaying a mirror image of the true waveform simultaneously on both sides of the baseline is most likely caused by:

Accepted Answer

Doppler gain set too high, causing cross-talk (ghosting) artifact

Answer

Aliasing due to velocity exceeding the Nyquist limit

Answer

Insonation angle of 90 degrees creating a bidirectional artifact

Answer

Wall filter set too low, allowing vessel wall signals through

Question 7

The time-averaged mean velocity (TAMV) is the denominator used to calculate which Doppler index?

Accepted Answer

Pulsatility Index (PI)

Answer

Resistive Index (RI)

Answer

Systolic-to-Diastolic (S/D) Ratio

Answer

Acceleration Index (AI)