What are the two kinds of color doppler?
- Velocity
- Power (amplitude)
Color is another way to display what information?
- Frequency shift
- Direction
What does the color bar entail?
Flow direction and flow velocity.
What does the color box entail?
Steer direction and sample volume size and placement.
What does the number associated with the color bar mean?
It is the mean veocity assigned to color in m/sec.
What is the color on top in a color bar assigned to?
Flow towards the beam.
What color is the baseline?
Black.
What is the color on the bottom of the color bar assigned to?
Flow away from the beam.
Can the color bar be inverted?
Yes.
How is colored formed?
It is formed with data fro multiple doppler beams running parallel to the color box edges.
What must there be between the beam and flow direction?
An angle.
How do you want to steer the steerbox?
Steer the box to the side where the vessel dives.
In order to good a good transverse color image, how should you hold the probe?
Tip the pobe towards the head.
What is the color scale initally set to for arteries?
.30
What is the scale initally set to for veins?
.10
What happens if the color scale is too high?
Lose low velocities along the wall/
What happens if the scale is set too low?
Aliasing will occur.
Higher frequency shifts will wrap around and show up from the bottom.
How should you turn on the color gain?
Turn the gain up until it shows outside the vessel, then turn down to show color wall to wall.
When does aliasing occur?
- Stenosis
- Low angle
- Scale low (PRF)
- Tortuosity (high velocity on curves and lower angle on vertical areas)
In long view, , how should you steer the color box in order to get the correct angle?
Steer the color box to the side of the vessel that dives down.
In transverse, how shou;d you position the probe in order to get a correct angle?
Tilt twards the head.
True of False:
Color doppler is another way to display frequency shifts and direction of flow besides PW spectral waves.
True
What color controls are available on the duplex equipment to change the color box?
a. Box steer direction
b. Box size
c. Box placement on the screen
a. Box steer direction.
The color on the top of the color bar is assigned to which type of flow?
a. Turbulent flow
b. Flow towards the doppler beam
c. Normal flow
d. Weak flow
b. Flow towards the doppler beam.
What is the number at the top of the color bar?
a. Peak velocity of the lood assigned to the very top color.
b. Mean velocity of the blood assigned to the very top color.
c. DIastolic velocity average shown by color doppler.
b. Mean velocity of the blood assigned to the very top color.
True or False:
The color on the bottom of the color bar will be assigned to flow running 90° to the color beam.
False.
A curvy vessel may show red and blue colors at seperate areas of the vessel with black between them. This indicates_____
a. Flow towards the head and toward the feet at each section of the vessel.
b. Flow towards the beam and away from the beam in each section of the vessel.
c. High velocities demonstrating aliasing.
c. High velocities demonstrating aliasing.
How do you get a color doppler angle in transverse view?
Point the probe towards the head.
Name the two maneuvers done to achieve appropriate color gain?
What do you look for in a color image of a vessel to see it as normal?
Color fill wall to wall with little to no aliasing.
What is an appropriate color scale to use when you start looking in color at an artery? You can always adjust later.
a. .10
b. .20
c. .30
d. 40
c. .30
What will you miss if your color scale is set too high for the velocities?
a. Low velocities
b. High velocities
a. Low velocities.
What will happen if you have your scale set two low for the velocities?
a. You will miss low velocities
b. Aliasing will occur.
c. Color will bleed outside of the vessel.
b. Aliasing will occur.
