Unit 7: Normal COlor

Question 1

What 2 things does color help identify?

Answer 1

1. Idenitfying course of vessels
2. Identifying areads of interest for doppler

Question 2

Should you depend on color alone?

Answer 2

No, you should always use a PW doppler. Especially when an occlusion is present.

Question 3

What does a frozen image in color represent?

Answer 3

It represents velocity AT THAT MOMENT IN TIME and may appear differently in the next frame,

Question 4

What 4 things does velocity color display show?

Answer 4

1. Displays mean velocities
2. Direction of flow
3. Course of vessels
4. areas to investigate with a PW doppler.

Question 5

What is the color scale used for?

Answer 5

1. Avoid aliasing in the vessel
2. Demonstrate areas of disturbances
3. Fill vessel wall to wall, decrease in blb.

Question 6

How should you approach and move in order to get color in the vertebral artery?

Answer 6

Take an AP approach, align CCA then move slightly lateral and point slightly medial if not seen.

Decrease scale, increase gain.

Question 7

Is the vertebral vein superfical or deep to the artery?

Answer 7

Superficial.

Question 8

What does color help with?

Answer 8

Color orientation.

Question 9

A color mosaic may occur for all of these reasons except?

A. There is a high velocity at a stenosis

B. The PRF is too low for the velocities

C. There is a flow disturbances

D. There is laminar flow.

Answer 9

D. There is laminar flow.

Question 10

What are 4 possible reasons for color aliasing?

Answer 10

1. Scale too low for velocities present
2. Low angle creates higher frequency shifts
3. High velocities present from stenosis
4. Post-stenotic turbulence creates a variety of doppler beam to flow angles, high velocities, directional changes.

Question 11

What is the downfall of power color?

Answer 11

Arteries and veins look the same.

Arteries and veins sometimes cross and appear to be the same vessel with power color, especially in the high neck where a branch of the IJV crosses the ICA.

Question 12

What is flow separation?

Answer 12

Flow separation is the separation of the flow layers (laminar flow) whereby the outer wall layers (away from the FD) actually reverse direction.

Question 13

Changes in bulb diametere from small to large results in what?

Answer 13

Flow separation.

Question 14

What is the best thing to try first if there is color aliasing throughout the entire vessel in long view?

A. Increase scale

B. Decrease gain

C. Move baseline up

D. Steer the baseline the opposite direction

Answer 14

A. increase scale

Question 15

There is no color in a clearly seen vessel. What should you do first to try to see color?

A. Increase scale

B. Decrease baseline

C. Increase gain

D. Steer opposite direction

Answer 15

C. increase gain

Question 16

You see the CCA and ICA in red, but no color in the bulb with the scale set at .32. Which of the following will be most likely to show color in the bulb?

A. Increase scale

B. Decrease scale

C. Increase gain

D. Decrease gain

Answer 16

B. Decrease scale AND C. Increase gain