Lesson 21 (Part 2)

Question 1

Was does cos0 equal?

Answer 1

1

- hitting the vessels straight on

Question 2

What does cos 30 equal?

Answer 2

0.87

Question 3

What does cos 60 equal?

Answer 3

0.5

Question 4

What does cos 90 equal?

Answer 4

0

- hitting the vessels perpendicular (dont see anything)

Question 5

What is the ideal angle?

Answer 5

cos 0

Question 6

What does cos0 appear as in the doppler ultrasound?

Answer 6

Black

- no doppler shift (no flow)

Question 7

What happens to the velocity measurement when the doppler shift measurement goes down?

Answer 7

It goes down also

Question 8

What happens when you incorporate cos into the formula?

Answer 8

It lessens the doppler shift

Question 9

What shape do we get with doppler?

Answer 9

Parallelogram

Question 10

What are 3 techniques to try and get closer to cos0?

Answer 10

1. Heel toe
2. Phasing
   - steering
3. Angle correct

Question 11

Angle correct

Answer 11

We ‘tell’ the machine that we’re off, and it compensates

Question 12

What does angle correct do?

Answer 12

Increases our velocity back up to where it should be

Question 13

What happens when we increase the angle correct?

Answer 13

We increase the error in the speed calculations

Question 14

What is the % error of 0 deg?

Answer 14

0.4%

Question 15

What is the % error at 70deg?

Answer 15

32%

Question 16

What angle correction do we work under in real life?

Answer 16

60deg