# Chapter 5 Flashcards Preview

## SON111AB-Physics > Chapter 5 > Flashcards

Flashcards in Chapter 5 Deck (53)
1
Q

Autocorrelation

A

a rapid technique, used in most color Doppler instruments; to obtain mean Doppler shift frequency

2
Q

baseline shift

A

movement of the zero Doppler shift frequency or zero flow speed line up or down on a spectral display

3
Q

Bernoulli effect

A

pressure reduction in a region of high flow speed

4
Q

bidirectional

A

indicating Doppler instruments capable of distinguishing between positive and negative Doppler shifts

5
Q

clutter

A

noise in the Doppler signal that generally is caused by high amplitude, Doppler shifted echoes from the heart or vessel walls.

6
Q

color- Doppler display

A

the display that is presented in color

7
Q

compliance

A

Distensibility; nonrigid stretch-ability of vessels

8
Q

continuous wave doppler

A

a Doppler device or procedure that used continuous wave ultrasound

9
Q

cosine

A

the length of side B divided by the length of side C

10
Q

disturbed flow

A

flow that cannot be described by straight, parallel streamlines

11
Q

Doppler angle

A

the angle between the sound beam and the flow direction

12
Q

Doppler effect

A

a change in frequency caused by reflector motion

13
Q

Doppler equation

A

the math description of the relationship between the Doppler shift, frequency, Doppler angle, propagation speed, and reflector speed

14
Q

Doppler-power display

A

color Doppler display in which colors are assigned according to the strength

15
Q

Doppler shift

A

reflected frequency minus incident frequency, the change in frequency caused by motion

16
Q

Doppler spectrum

A

the range of freq present in Doppler shifted echoes

17
Q

duplex instrument

A

an ultrasound instrument that combines gray scale sonography with pulsed Doppler and possibly CW doppler

18
Q

eddies

A

regions of circular flow patterns present in turbulence

19
Q

ensemble length

A

number of pulses used to generate one color Doppler image scan line

20
Q

fast Fourier transform

A

digital computer implementation of the Fourier transform

21
Q

filter

A

an electric circuit that passes frequencies within a defined range

22
Q

fluid

A

a material that flows and conforms to the shape of its container; gas or liquid

23
Q

flow

A

to move in a stream; volume flow rate

24
Q

frequency spectrum

A

the range of Doppler shift frequencies present in the returning echoes

25
Q

gate

A

a device that allows only echoes from a selected depth arrival time to pass

26
Q

hue

A

the color perceived based on the frequency of light

27
Q

inertia

A

resistance to acceleration

28
Q

laminar flow

A

flow in which fluid levels slide over each other in a smooth, orderly manner, with no mixing between layers

29
Q

luminance

A

brightness of presented hue and saturation

30
Q

parabolic flow

A

laminar flow with a profile in the shape of a parabola

31
Q

A

two signals differing by one fourth of a cycle

32
Q

plug flow

A

flow with all fluid portions traveling with the same flow speed and direction

33
Q

poise

A

unit of velocity

34
Q

Poiseuille equation

A

the dependence of volume flow rate on pressure, vessel length and radius, and fluid viscosity

35
Q

priority

A

the gray scale echo strength below which color Doppler info is shown on a display

36
Q

pulsatile flow

A

flow that accelerate and decelerates with each cardiac cycle

37
Q

pulsed doppler

A

a Doppler device or procedure that uses pulsed wave ultrasound

38
Q

range gating

A

selection of the depth from which echoes are accepted based on echo arrival time

39
Q

resistance

A

pressure difference divided by volume flow rate for steady flow

40
Q

sample volume

A

the anatomic region from which pulsed Doppler echoes are accepted

41
Q

saturation

A

the amount of hue present in a mix with white

42
Q

spectral analysis

A

separation of freq in a Doppler signal for display as a Doppler spectrum.

43
Q

A

the widening of the Doppler shift spectrum

44
Q

spectral Doppler display

A

the presentation of Doppler info in a quantitative form of Doppler shift verses time

45
Q

spectrum analyzer

A

a device that derives a freq spectrum from a complex signal

46
Q

stenosis

A

narrowing of a vessel lumen

47
Q

streamlines

A

a line representing the path of motion of a particle of fluid

48
Q

turbulence

A

random, chaotic, multi-directional flow of a fluid with mixing between layers, flow that is not laminar

49
Q

variance

A

square of standard deviation one of outputs of the auto-correlation process.

50
Q

viscosity

A

resistance of a fluid to flow

51
Q

volumetric flow rate

A

volume of fluid passing a point per unit of time

52
Q

wall filter

A

an electric filter that passes freq above a set level and eliminates strong, low freq Doppler shifts from pulsating heart or vessel walls or tissue motion

53
Q

window

A

an anechoic region appearing beneath echo frequencies presented on a Doppler spectral display