Doppler Principles and Applications Flashcards
6 cards from real ARDMS ECHO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Doppler Principles and Applications flashcards as text
What is the Nyquist limit in pulsed wave Doppler echocardiography?
Answer: Half the pulse repetition frequency
The Nyquist limit equals half the pulse repetition frequency (PRF); exceeding it causes aliasing in pulsed wave Doppler.
Which Doppler modality is best suited for measuring high-velocity jets such as severe aortic stenosis?
Answer: Continuous wave Doppler
Continuous wave Doppler has no PRF limitation and can accurately measure high-velocity jets without aliasing.
What effect does increasing the angle of insonation (θ) beyond 20° have on Doppler velocity measurements?
Answer: Underestimates true velocity
The Doppler equation uses cosine θ; as θ increases beyond 20°, cosine decreases, causing underestimation of true blood flow velocity.
In color flow Doppler, what does aliasing (color reversal to the opposite color) indicate?
Answer: Velocities exceeding the Nyquist limit
Color aliasing occurs when detected velocity exceeds the Nyquist limit, causing the display to wrap to the opposite color.
Which Doppler technique allows simultaneous visualization of flow direction and velocity across a 2D image?
Answer: Color flow Doppler
Color flow Doppler maps mean blood flow velocities across a 2D sector, color-coding direction and relative velocity.
What is the primary advantage of tissue Doppler imaging (TDI) over conventional Doppler in diastolic assessment?
Answer: It measures myocardial wall motion velocity and is less preload dependent
TDI measures low-velocity, high-amplitude myocardial motion and the resulting e' velocity is relatively preload independent, useful for diastolic assessment.