Chapters 1 & 2 Flashcards

1
Q

Color-doppler display

A

color-coded 2d and 3d presentations of doppler info. (Superimposed on gray-scale images.) Flow directions toward and away from the transducer are presented as different colors on the display.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Doppler effect

A

a change in frequency caused by reflector (The structure that sends the echoes back) motion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Gray-scale image

A

image composed of different ranges of brightnesses (gray levels) between white and black.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Image

A

A reproduction, representation, or imitation of the physical form of a person or thing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

linear image

A

s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Operating principle 1

A

Positional info is determined by knowledge of the direction of the pulse when it enters the patient and by measurement of the time it takes for each echo to return to the transducer. The proper location to present the echo can then be determined from a starting point on the display (usually at the top). With knowledge of the sound speed, the instrument uses the echo arrival time to determine the depth of the structure that produced that echo.
depth of a structure is determined by the measurement of the time it takes for the echo to return to the transducer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Operating principle 2

A

sends several pulses of ultrasound through the cross section of anatomy to be imaged but does not produce a one-for-one correspondence of pulse and displayed scan line. Instead, all the echo information from throughout the anatomic cross section sis collected, and then massive computational processes determine the location and strength of each echo produced at each location in the anatomy. This approach is used in recent instruments and produces improved quality compared with principle 1.
sends several pulses and instead of a one-for-one correspondence of pulse and scan line, all the echo info is collected and copmuters determine the location and strength of each echo. New approach. Improved image quality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pulse-echo technique

A

Ultrasound imaging in which pulses are reflected and used to produce a display.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Scan line

A

a line produced on a display that represents ultrasonic echoes returning from the body. A sonographic image is composed of many such lines.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sector image

A

An anatomic image presented in a pie slice-shaped format.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Sonography

A

written sound. The use of ultrasound in medical anatomic and flow imaging. Can be 2D or 3D.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Spectral-doppler display

A

using doppler info for quantitative analysis. The one that has like the chart. The presentation of Doppler info in a quantitative form of Doppler shift versus time. Visual display of a Doppler spectrum. The location from which the spectral-doppler info was acquired is displayed as well.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Transducer

A

generates the ultrasound pulses and receives the returning echoes. Converts energy from one form to another (mechanical to electrical in sonography)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Ultrasound

A

Sound having frequency greater than what humans can hear. Greater than 20khz.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Volume imaging

A

3D imaging. Is like creating slices and then combining them like in MRI and CT.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ultrasound instrument

A

is the system aka the ultrasound machine. Processes the echoes and presents them as visible dots on the display.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the pulse-echo principle used in sonographic imaging

A

Pulses of ultrasound generated by a transducer are sent into the patient where they produce echoes at organ boundaries and within biological tissues. These echoes return to the transducer where th4ey are detected and presented on the display of a sonographic instruemtn. // Ultrasound pulses are sent into the tissues to interact with them and to obtain info about them. Then echoes return from the tissues providing info that enbables anatomic imaging and observation of motion and flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

List the differences between operating Principles 1 and 2

A

w

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the image formats used in sonography

A

2D images are presented in linear and/or sector forms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

List the ways in which Doppler information is presented.

A

Audible, color-doppler, and spectral-doppler forms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Diagnostic ultrasound is between?

A

2 MHz-15MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The brightness of each dot corresponds to what?

A

the echo strength.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Absorption

A

conversion of sound to heat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Acoustic

A

having to do with sound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Acoustic variables

A

pressure, density, and particle vibration; sound wave quantities that vary in space and time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Amplitude

A

maximum variation of an acoustic variable or voltage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Attenuation

A

decrease in amplitude and intensity with distance as a wave travels through a medium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Attenuation coefficient

A

attenuation per centimeter of wave travel.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Backscatter

A

sound scattered back in the direction from which it originally came.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Bandwidth

A

range of frequencies contained in an ultrasound pulse; range of frequencies within which a material, device, or system can operate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Compression

A

reduction in differences between small and large amplitudes. Region of high density and pressure in a compressional wave.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Constructive interference

A

combination of positive or negative pressures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Continuous wave (CW)

A

a wave in which cycles repeat indefinitely; not pulsed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Contrast agent

A

a suspension of bubbles or particles introduced into circulation to enhance the contrast between anatomic structures, thereby improving their imaging.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Coupling medium

A

a gel used to provide a good sound path between a transducer and the skin by eliminating the air between the two.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Cycle

A

one complete variation of an acoustic variable.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Decibel (dB)

A

unit of power or intensity ratio; the number of decibels is 10 times the logarithm of the power or intensity ratio.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Density

A

mass divided by volume.

39
Q

Destructive interference

A

: combination of positive and negative pressures.

40
Q

Duty factor

A

fraction of time that pulsed ultrasound is on.

41
Q

Echo

A

reflection.

42
Q

Energy

A

capability of doing work.

43
Q

Fractional bandwidth

A

bandwidth divided by operating frequency.

44
Q

Frequency

A

number of cycles per second.

45
Q

Fundamental frequency

A

the primary frequency in a collection of frequencies that can include odd and even harmonics and subharmonics.

46
Q

Harmonics

A

frequencies that are even and odd multiples of another, commonly called fundamental or operating frequency.

47
Q

Hertz (Hz)

A

unit of frequency, one cycle per second; unit of pulse repetition frequency, one pulse per second.

48
Q

Impedance

A

density multiplied by the sound propagation speed.

49
Q

Incidence angle

A

angle between incident sound direction and a line perpendicular to the boundary of a medium.

50
Q

Intensity

A

: power divided by area.

51
Q

Intensity reflection coefficient

A

reflected intensity divided by incident intensity; the fraction of incident intensity reflected.

52
Q

Intensity transmission coefficient

A

transmitted intensity divided by incident intensity; the faction of incident intensity transmitted into the second medium.

53
Q

Interference

A

combinations of positive and/or negative pressures.

54
Q

Kilohertz (KHz)

A

one thousand hertz.

55
Q

Longitudinal wave

A

wave in which the particle motion is parallel to the direction of wave travel.

56
Q

Medium

A

material through which a wave travels.

57
Q

Megahertz (MHz)

A

one million hertz.

58
Q

Nonlinear propagation

A

sound propagation in which the propagation speed depends on pressure causing the wave shape to change and harmonics to be generated.

59
Q

Oblique incidence

A

sound direction that is not perpendicular to media boundaries.

60
Q

Penetration

A

imaging depth.

61
Q

Period

A

: time per cycle.

62
Q

Perpendicular

A

geometrically related by 90 degrees.

63
Q

Perpendicular Incidence

A

sound direction that is perpendicular to the boundary between media.

64
Q

Power

A

rate at which work is done; rate at which energy is transferred.

65
Q

Pressure

A

: force divided by the area in a fluid.

66
Q

Propagation

A

progression or travel.

67
Q

Propagation speed

A

speed at which a wave moves through a medium.

68
Q

Pulse

A

A brief excursion of a quantity from its normal value; a few cycles.

69
Q

Pulse duration

A

interval of time from beginning to end of a pulse.

70
Q

Pulse-repetition frequency

A

number of pulses per second; sometimes called pulse repetition rate.

71
Q

Pulse-repetition period

A

interval of time from the beginning of one pulse to the beginning of the next.

72
Q

Pulsed ultrasound

A

ultrasound produced in pulsed form by applying electric pulses or voltages of one or a few cycles to the transducer.

73
Q

Range equation

A

relationship between roundtrip pulse travel time, propagation speed, and distance to a reflector.

74
Q

Rarefaction

A

region of low density and pressure in a compressional wave.

75
Q

Rayl

A

unit of impedance.

76
Q

Reflection

A

portion of sound returned from a media boundary; echo.

77
Q

Reflection angle

A

angle between the reflected sound direction and a line perpendicular to the media boundary.

78
Q

Reflector

A

media boundary that produces a reflection; reflecting surface.

79
Q

Refraction

A

change of sound direction on passing from one medium to another.

80
Q

Scatterer

A

an object that scatters sound in many directions because of its small size or its surface roughness.

81
Q

Scattering

A

diffusion or redirection of sound in several directions upon encountering a particle suspension or a rough surface.

82
Q

Shear wave

A

transverse wave.

83
Q

Sound

A

traveling wave of acoustic variables.

84
Q

Spatial pulse length

A

length of space over which a pulse occurs.

85
Q

Speckle

A

the granular appearance of images and spectral displays that is caused by the interference of echoes from the distribution of scatterers in tissue.

86
Q

Specular reflection

A

: reflection from a large (relative to wavelength), flat, smooth boundary.

87
Q

Stiffness

A

property of a medium; applied pressure divided by the fraction volume change produced by the pressure.

88
Q

Strength

A

nonspecific term referring here to amplitude or intensity.

89
Q

Transmission angle

A

angle between the transmitted sound direction and a line perpendicular to the media boundary.

90
Q

Transverse wave

A

a wave in which the particle motion is perpendicular to the direction of wave travel, also called a shear wave.

91
Q

Ultrasound

A

sound having a frequency greater than what humans can hear, that is, greater than 20kHz.

92
Q

Wave

A

traveling variation of one or more quantities.

93
Q

Wavelength

A

length of space over which a cycle occurs.