Lesson 23 (Part 1) Flashcards Preview

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Flashcards in Lesson 23 (Part 1) Deck (33)
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1

What does spectral doppler detect? (4)

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

2

When is the peak velocity?

During systolic

3

When is the end velocity?

During diastolic

4

What is spectral doppler also known as? (2)

1. Pulsed doppler
2. Pulsed wave doppler

5

What does spectral doppler fire along?

A single scan line

6

How many pulses per cycle are there for spectral doppler?

5-30

7

Sample volume

Is a specific area that is being assessed
- the gate

8

Range gating

Being able to select information from a specific depth

9

What are you looking at in a smaller gate?

A higher velocity

10

What are 3 benefits for a smaller gate?

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

11

What is the formula for effective sample length?

1/2 SPL + gate length

12

What is another term for sample width?

Beam width

13

What is sample volume dependant on?

The user
- user defined

14

What is a larger gate used for?

To look for a vessel/signal

15

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

Time

16

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

Doppler shift/velocity

17

How does all blood move?

As a unit

18

When is a range of velocities obtained?

At any particular moment in time

19

Where does spectral doppler occur?

Within the signal processor

20

What is the known as the gate amplifier?

Beam former

21

What does quadrature phase detector allow?

Detection of bidirectional Doppler
- shows +/- shifts

22

What does a filter do?

Gets rid of the sum

23

What does the spectrum analyzer determine? (2)

1. Each Doppler shift frequency
2. Its strength

24

Where does fast fourier transform occur?

Within the spectrum analyzer

25

Fast fourier transform

Mathematical technique to figure out the frequency spectrum

26

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

Results sent to be displayed on the spectral display

27

FFT

Fast fourier transform

28

What does spectral display show?

Spectral waveforms

29

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

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

30

What factors can affect direction for spectral doppler?

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