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

Loading flashcards...

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