Week 4 - Lesson 2

Question 1

What must be understood before inverting the colour on a vessel?

Answer 1

The correct direction of flow

• try to have arteries in red
• try to veins in blue

Question 2

What does the colour red indicate on colour doppler?

Answer 2

Flow towards the transducer

Question 3

What does the colour blue indicate on colour doppler?

Answer 3

Flow away from the transducer

Question 4

What does a colour doppler image with an oversized box result in? (2)

Answer 4

1. Decreased frame rate

2. Poor resolution of colour within the vessel

Question 5

What does an appropriate sized colour box demonstrate? (2)

Answer 5

1. Increase frame rate

2. Improved colour image quality

Question 6

How does wasted space in the far field affect the resolution?

Answer 6

Due to increased pulse transit time

- slower PRF

Question 7

What could wasted space in the far field produce?

Answer 7

Aliasing of colour flow

Question 8

What influences frame rate?

Answer 8

PRF

Question 9

What happens if you increase PRF?

Answer 9

You increase frame rate

Question 10

What kind of relationship does PRF and frame rate have?

Answer 10

Proportional

Question 11

When do you use steering in a colour box?

Answer 11

When the vessel is parallel or slightly angled

Question 12

What happens to the sensitivity of the transducer when steering is applied?

Answer 12

It decreases

Question 13

When do you use a straight colour box?

Answer 13

When vessels are steeply angled

Question 14

Which way do you steer the colour box?

Answer 14

So that it is parallel to the flow

- not angled in the opposite direction

Question 15

What do you have to do if you invert the colour doppler?

Answer 15

You need to do the same with spectral doppler

Question 16

How do you steer a colour box in bifurcation?

Answer 16

You may need to angle the colour box twice to delineate each branch with the most clarity as the vessels usually are not parallel

Question 17

What do you want in your first bifurcation picture?

Answer 17

You want to optimize the posterior vessel

Question 18

What do you want in your second bifurcation picture?

Answer 18

You want to optimize the anterior vessel

Question 19

What kind of settings do carotid arteries have?

Answer 19

High velocity ranges

- due to higher arterial flow

Question 20

What kind of scale do you need for venous flow?

Answer 20

Lower scale

- because venous flow is much slower in nature

Question 21

When will colour aliasing occur?

Answer 21

If a venous setting is used to visualize arterial flow

Question 22

What do higher numbers in colour doppler represent?

Answer 22

Brighter colours

Question 23

What do lower numbers in colour doppler represent?

Answer 23

Lower colours

Question 24

What is the normal flow for the portal vein?

Answer 24

20-30 cm/s

Question 25

What is the flow of the portal vein when there is pathology?

Answer 25

Slower than 20-30 cm/s

Question 26

Why can a vessel appear occluded?

Answer 26

If the scale of a vessel is incorrect

- especially in veins

Question 27

What happens if the colour scale is set too high?

Answer 27

The venous echoes will not be represented

- due to slower flow

Question 28

What does the velocity of the inner portion of a tricky vessel be?

Answer 28

Moves slower

Question 29

What does the velocity of the outer portion of a tricky vessel be?

Answer 29

Moves faster