Doppler Review

Question 1

What is the doppler effect?

Answer 1

Change in frequency caused by motion

Question 2

Factors that affect doppler shift

Answer 2

1. Motion of reflector
2. Direction
3. Velocity
4. Angle
5. Transmitted frequency
6. Propagation speed

Question 3

How to calculate doppler shift?

Answer 3

DS = Fr (R) - Fr (T)

Question 4

Doppler shift is proportional to what?

Answer 4

Blood flow speed and operating frequency

Question 5

In what direction are reflectors moving in a negative doppler shift?

Answer 5

Away from transducer

Question 6

What is the doppler equation?

Answer 6

F (DS) = 2 Fo x V/ c

Question 7

What is the angle of insonification?

Answer 7

Angle between the direction of blood flow and direction of sound propagation

Question 8

Increasing the doppler angle will do what to the accuracy?

Answer 8

Decrease accuracy

Question 9

Increasing doppler cosine will do what to the accuracy?

Answer 9

Increase accuracy

Question 10

An angle of 0 is a cosine of?

Answer 10

1.0 - Most accurate

Question 11

A cosine of 0 is an angle of?

Answer 11

90 degrees - no DS

Question 12

As doppler angle increases, what happens to cosine?

Answer 12

Decreases

Question 13

As doppler angle increases, what happens to the doppler shifted frequency?

Answer 13

Decreases