Optimizing Doppler Imaging Flashcards
What is the effect of normal incidence (90 degrees) on Doppler shift?
NO Doppler shift occurs
The cosine of 90 degrees is 0, resulting in no Doppler shift.
What should the angle of the color box be relative to the direction of flow?
Steered at any angle other than 90 degrees
What happens if the color gain is too high?
Color appears throughout the color box
What happens if the color gain is too low?
No color is present
What should be checked before adjusting the color gain?
Angle of color box to vessel
What is the consequence of increasing the wall filter?
Rejects low Doppler shifts
How does increasing the wall filter affect higher velocity flows?
Does not affect appearance
What effect does increasing the PRF (pulse repetition frequency) have on sensitivity?
Makes the transducer less sensitive to low Doppler shifts
What visual effect occurs on the Doppler image with normal incidence?
NO color appears on the image
Where is color created in Doppler imaging?
In the lumen of the blood vessels
What does ‘color confetti’ indicate in Doppler imaging?
Color appears throughout the color box
What appears throughout the spectrum when there is too low of color gain?
Gray scale noise
What happens to all gray scale in the image when there is too high of pulsed Doppler gain?
ALL gray scale will disappear
What is eliminated with pulsed Doppler when low velocity flows are present?
Ghosting of color Doppler
What visual artifact is still present even after adjustments?
Aliasing
