Flashcards in Lesson 22 (Part 2) Deck (32)
Where does the data go for colour doppler once the instrument processes it?
On the display
What kind of parameters does colour doppler use? (3)
What colour is being displayed
The amount of colour being shown
How are stronger echoes demonstrated in colour doppler?
- red or white
How are weaker echoes demonstrated in colour doppler?
- grey to black
What can be done to affect the effectiveness of the colour doppler examination? (9)
1. Colour box/window
- size can be changed
9. Wall filter
What does changing the shape of the colour box/window do? (3)
1. Affects the frame rate
2. Affects temporal resolution
3. Changes the coverage
What does a colour map do?
Helps to interpret data
What does the colour map interpret? (3)
1. Mean velocities
2. Direction of flow/sign
Change in colour from left to right
What is the most commonly used spectrum for colour doppler?
Red to blue
What does red represent on the colour map?
A positive shift
What does blue represent on the colour map?
A negative shift
What does invert do in colour doppler?
Flips the colour map
What does invert do?
Adjusts the representation
- doesnt change the direction of flow
What does baseline mean?
No doppler shift
- zero point
Why does baseline help?
IF you have all positive flow you can switch the baseline so there is less blue and more red showing a more detailed map of the flow
What does no doppler shift appear as?
Can we control PRF in doppler and in 2D?
No, only in doppler
- not in 2D
What is the unit for our PRF?
What is the unit for our scale?
How does changing PRF help in colour doppler?
Can pick up faster or slower speeds by increasing or decreasing the PRF
What happens to PRF if we decrease depth?
- more superficial
What happens to PRF if we increase depth?
- deeper structures
What does PRF change?
What happens to the scale if PRF decreases?
What happens to the scale if PRF increases?