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Spectral Doppler Waveform Analysis Flashcards

7 cards from real ARDMS SPI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Spectral Doppler Waveform Analysis flashcards as text

  1. Which formula correctly represents the Resistive Index (RI)?

    Answer: (PSV - EDV) / PSV

    The RI (Pourcelot index) = (PSV - EDV) / PSV, producing a value between 0 and 1 that reflects downstream vascular resistance.

  2. Spectral broadening on a Doppler waveform indicates:

    Answer: A wide range of velocities simultaneously present within the sample volume

    Spectral broadening occurs when multiple velocity components are detected within the sample volume, filling in the clear spectral window beneath the waveform envelope.

  3. The spectral window in a Doppler display represents:

    Answer: The clear area beneath the systolic peak where few slow-moving cells are present

    The spectral window is the clear area beneath the waveform envelope, indicating relatively uniform laminar flow where most cells travel at similar velocities with few slow-moving cells near the vessel wall.

  4. Which Doppler insonation angle range provides the most accurate velocity measurement?

    Answer: 60 degrees or less

    Angles of 60 degrees or less are recommended because the cosine function changes gradually in this range, minimizing the amplification of small angle errors in velocity calculations.

  5. A high-resistance spectral Doppler waveform is characterized by:

    Answer: Low or absent end-diastolic velocity with a sharp systolic peak

    High-resistance vessels (such as resting peripheral arteries) display a sharp systolic peak with little or no diastolic flow and may demonstrate brief flow reversal in early diastole.

  6. Aliasing on a spectral Doppler display is caused by:

    Answer: PRF set too low relative to the Doppler frequency shift

    Aliasing occurs when the Doppler frequency shift exceeds half the PRF (the Nyquist limit), causing high-velocity signals to wrap around and appear on the opposite side of the baseline.

  7. The Pulsatility Index (PI) is calculated as:

    Answer: (PSV - EDV) / TAMV

    PI = (PSV - EDV) / TAMV (time-averaged mean velocity); unlike RI, PI can exceed 1.0 and can be calculated even when end-diastolic flow is zero or reversed.