Study guide for 18, 19, 20

Question 1

Movement of fluid from one location to another?

Answer 1

Velocity

Question 2

Fluid moving with a variable velocity accelerates and decelerates?

Answer 2

Pulsitile flow

Question 3

Movement of fluid from one location to another that accelerates and decelerates w/ respiration?

Answer 3

Phasic Flow

Question 4

Flow pattern seen with normal physiological states?

Answer 4

Laminar Flow

Question 5

Chaotic flow in many directions and speeds?

Answer 5

Turbulent Flow

Question 6

Frictional loss, blood slide along vessel wall is considered what?

Answer 6

Heat?

Question 7

Reynolds number, turbulent flow?

Answer 7

> 2,000

Question 8

What the effects of stenosis are?

Answer 8

change in flow direction
↑ velocity as vessels narrows
turbulence downstream from the stenosis
pressure gradient across the stenosis
loss of pulsatility

Question 9

Next 5 questions are about hydrostatic pressure?

These are all in supine

Answer 9

Ankle 140mmHg heart 0mmHg 140 mmHg (140 + 0)
Knee ‘’
mid Chest ‘’
Top of head’’

Question 10

Doppler shift provide info about what?

Answer 10

Velocity

Question 11

Positive and negative Doppler shift?

Positive

Answer 11

toward transducer
reflected higher than transmitted
arterial

Question 12

Positive and negative Doppler shift?

Negative

Answer 12

away from transducer
reflected lower than transmitted
venous

Question 13

Typical range of Doppler shift found in imaging examinations?

Answer 13

Audible

20Hz - 20kHz

Question 14

If the sample volume is deep, the PRF and Nyquist limit is what?

Answer 14

low, creates aliasing

Question 15

Phenomenon high velocity is negative?

Answer 15

Aliasing

Question 16

Five ways to eliminate aliasing?

Answer 16

1. adjust scale
2. shallower
3. ↓ frequency
4. Baseline
5. Continuous Wave

Question 17

Large and small sample volumes, which will fill in on Doppler?

Answer 17

Large, spectral broading

Question 18

X and Y axis on Doppler Spectrum?

X

Answer 18

Time

Question 19

X and Y axis on Doppler Spectrum?

Y

Answer 19

Shift or Velocity

Question 20

Doppler shift inversely related to?

Answer 20

speed of sound in the medium

Question 21

What is the basic Doppler system that simple identifies the blood flow of the presence of a frequency shift?

Answer 21

power doppler (MW pg 333)

Question 22

Gray shades on Doppler spectrum related to two things?

Answer 22

amplitude of reflected signal

number of blood cells creating the reflection

Question 23

Doppler Spectrum, high waveform is a high frequency or low?

Answer 23

?

I think this is high freq. because they are directly related (MW pg 308)

Question 24

What is the Doppler Effect?

Answer 24

the change in frequency

Question 25

Difference between speed and velocity? Speed

Answer 25

magnitude (distance red blood cells travel in 1 second)

Question 26

Difference between speed and velocity? Velocity

Answer 26

Magnitude and direction

Question 27

Angle w/ Doppler/ No angle?

Answer 27

0⁰: 1.0 90⁰: 0 180⁰: -1.0

Question 28

Primary advantage for a pulse wave Doppler?

Answer 28

select exact location | range resolution, range specificity

Question 29

Primary advantage for continuous Doppler?

Answer 29

ability to accurately measure very high velocity

Question 30

Bidirectional, type of processing?

Answer 30

Phase quadrature or quadrature detection

Question 31

FFT used in what type of what?

Answer 31

Is a computer-based technique, is use to process both pulsed and continuous wave Doppler signals

Question 32

Velocities that color flow measures?

Answer 32

mean or average

Question 33

Autocorrelation?

Answer 33

digital technique to analyses color flow Doppler less accurate but faster than FFT

Question 34

Limitation to color flow imaging?

Answer 34

it has range resolution and is subject to aliasing | pg 325 and esp physics pdf

Question 35

Area of integration in Doppler is called?

Answer 35

Sample Volume

Question 36

More accurate velocity measurement | Increased sensitivity low flow

Answer 36

Large Doppler packet advantages and disadvantages? Advantages

Question 37

More time needed to acquire data Reduced frame rate Decreased temporal resolution

Answer 37

Large Doppler packet advantages and disadvantages? Disadvantages

Question 38

How to measure low flow states?

Answer 38

Power Doppler?

Question 39

Inspiration vs Expiration Inspiration

Answer 39

``` Diaphragm ↓ Thoracic pressure ↓ Abdomen pressure ↑ Venous return to the heart ↑ Venous flow in legs ↓ ```

Question 40

Inspiration Vs Expiration Expiration

Answer 40

``` Diaphragm ↑ Thoracic pressure ↑ Abdomen pressure ↓ Venous return to the heart ↓ Venous flow in legs ↑ ```

Question 41

Venous pressure is low, pressure in veins?

Answer 41

Low

Question 42

37. What happens to shape of veins when pressure increases?

Answer 42

starts hourglass, then goes oval, then to round

Question 43

Hydrostatic pressure when standing

Answer 43

Ankle 140 mmHg, Far below heart level, 100mmHg , 240mmHg (140 + 100) Knee, 140mmHG, Somewhat below heart