Lesson 23 (Part 1)

Question 1

What does spectral doppler detect? (4)

Answer 1

1. Presence
2. Speed
3. Character
4. Direction of flow
5. Quantification of blood flow
   - this is super important

Question 2

When is the peak velocity?

Answer 2

During systolic

Question 3

When is the end velocity?

Answer 3

During diastolic

Question 4

What is spectral doppler also known as? (2)

Answer 4

1. Pulsed doppler

2. Pulsed wave doppler

Question 5

What does spectral doppler fire along?

Answer 5

A single scan line

Question 6

How many pulses per cycle are there for spectral doppler?

Answer 6

5-30

Question 7

Sample volume

Answer 7

Is a specific area that is being assessed

- the gate

Question 8

Range gating

Answer 8

Being able to select information from a specific depth

Question 9

What are you looking at in a smaller gate?

Answer 9

A higher velocity

Question 10

What are 3 benefits for a smaller gate?

Answer 10

1. Less noise
2. Better quality
3. More specific information

Question 11

What is the formula for effective sample length?

Answer 11

1/2 SPL + gate length

Question 12

What is another term for sample width?

Answer 12

Beam width

Question 13

What is sample volume dependant on?

Answer 13

The user

- user defined

Question 14

What is a larger gate used for?

Answer 14

To look for a vessel/signal

Question 15

What is on the X axis for a graph of spectral doppler?

Answer 15

Time

Question 16

What is on the y axis for a graph of spectral doppler?

Answer 16

Doppler shift/velocity

Question 17

How does all blood move?

Answer 17

As a unit

Question 18

When is a range of velocities obtained?

Answer 18

At any particular moment in time

Question 19

Where does spectral doppler occur?

Answer 19

Within the signal processor

Question 20

What is the known as the gate amplifier?

Answer 20

Beam former

Question 21

What does quadrature phase detector allow?

Answer 21

Detection of bidirectional Doppler

- shows +/- shifts

Question 22

What does a filter do?

Answer 22

Gets rid of the sum

Question 23

What does the spectrum analyzer determine? (2)

Answer 23

1. Each Doppler shift frequency

2. Its strength

Question 24

Where does fast fourier transform occur?

Answer 24

Within the spectrum analyzer

Question 25

Fast fourier transform

Answer 25

Mathematical technique to figure out the frequency spectrum

Question 26

Where are the results form the fast fourier transform sent to?

Answer 26

Results sent to be displayed on the spectral display

Question 27

FFT

Answer 27

Fast fourier transform

Question 28

What does spectral display show?

Answer 28

Spectral waveforms

Question 29

What does each point on the spectral display demonstrate? (3)

Answer 29

1. Direction (+/-)
2. Magnitude
   - speed
3. Amplitude
   - brightness

Question 30

What factors can affect direction for spectral doppler?

Answer 30

1. Whether it is positive or negative
   - coming towards the transducer or away from it
2. Steering the transducer

Question 31

What is everything above the baseline considered in spectral doppler?

Answer 31

Positive

Question 32

What is everything below the baseline considered in spectral doppler?

Answer 32

Negative

Question 33

Why is there 2 directions of flow?

Answer 33

Flow reversal

- this does not happen in every vessel (only in certain spots)