Lesson 21 (Part 2) Flashcards Preview

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Flashcards in Lesson 21 (Part 2) Deck (16)
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1

Was does cos0 equal?

1
- hitting the vessels straight on

2

What does cos 30 equal?

0.87

3

What does cos 60 equal?

0.5

4

What does cos 90 equal?

0
- hitting the vessels perpendicular (dont see anything)

5

What is the ideal angle?

cos 0

6

What does cos0 appear as in the doppler ultrasound?

Black
- no doppler shift (no flow)

7

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

It goes down also

8

What happens when you incorporate cos into the formula?

It lessens the doppler shift

9

What shape do we get with doppler?

Parallelogram

10

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

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

11

Angle correct

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

12

What does angle correct do?

Increases our velocity back up to where it should be

13

What happens when we increase the angle correct?

We increase the error in the speed calculations

14

What is the % error of 0 deg?

0.4%

15

What is the % error at 70deg?

32%

16

What angle correction do we work under in real life?

60deg