Doppler Basics Flashcards
what does Doppler provide?
clinical information about blood flow, including the direction and velocity as well as timing during the cardiac cycle
Doppler Effect
The frequency shift of waves that occurs as the source and observer change in motion relative to each other
The frequency will increase
As source and `observer move towards each other
The frequency will decrease
As source and obsever move away from each other
Doppler Frequency shift
refers to a change in or shift in received sound waves from the initial transmitted sound wave/pulse
Doppler shift can be _________and ________
positive and negative
Where is the Doppler Spectral display used
in both pulsed and continuous-wave Doppler to show the timing, direction, and velocity of blood flow
Pulse Wave Doppler
Send and receive signals art timed intervals so the location of where the sample volume is positioned can be known
what is a limit of pulsed-wave Doppler?
Higher velocities will exceed the Nyquist theorem limit and aliasing of the spectral trace will occur
Color Doppler
Helped in flow dynamics
ability to semiquantitate the degree of regurgitation or follow blood flow across shunts
Continuous Wave Doppler
Delivers continuous pulses out and back, it constantly transmits and receives with no specific pulse duration or sample volume area
what is an important component of the Doppler Equation
cosine of the angle between the ultrasound beam and the blood flow vector
