Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics REVIEW > Davies Quizlet Starred > Flashcards

Davies Quizlet Starred Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

A hydrophone measures (2)

A

Duty factor

Pressure amplitude

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

PHI stands for

A

Protected health information

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

What does mechanical index indicate on ultrasound system

A

Liklihood of cavitation during an US exam

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

Potential bio effect occuring through absorption of sound energy by tissue

A

Heating

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

You notice TI is greater than 1. Any increase in temp would most likely be greatest in

A

Bone

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

Motion of particles in a fluid is sometimes observed in an intense US beam. This is termed

A

Acoustic streaming

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

TI reading is 1. What does this indicate?

A

The output level is high enough that temperature could increase as much as 1 C if the transducer were held stationary

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

When scanning with pulsed-wave dop, you would affect the acoustic exposure by changing which of the following?

A

PRF

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

Tissue with the highest rate of attenuation

A

Lung

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

Propagation speed is lowest in which tissue

A

Fat

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

Purpose of gel coupling medium

A

Decrease impedance mismatch

Sound does not travel through air

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

While imaging a cyst, you notice shadowing posterior to each lateral border of the cyst. What is the source of the shadows?

A

Bending of the sound beam due to different media propagation speeds

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

Diffraction

A

Pattern produced by a sound beam after passing through a small aperture

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

Sound propagates faster in materials with greater

A

Stiffness

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

During an US, you would most likely encounter refraction in this fiew

A

Curved interface

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

Relationship to frequency and absorption

A

If frequency is doubled, absorption is doubled

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

While performing a sonogram, you encounter the following interfaces*** which will produce the weakest REFLECTED signal

A

Organ parenchyma/organ parenchyma

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

You are scanning a large mass that is composed primarily of fat. What is most likely to happen?

A

Axial misrepretation of objects distal to the mass on the screen due to the slower propagation speed through fat

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

When you change the transmit frequency, what is altered?

A

Number of cycles per second

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

When the sound beam is refracted, what may you detect on the ultrasound image?

A

lateral misregistration

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

What interaction of ultrasound and tissue is primarily responsible for imaging the internal structure of organs?

A

scattering

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

when you image a specular reflector, the strength of the recieved signal depends on (2)

A
  • angle of incidence

- difference in acoustic impedance

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

T/F frequency, intensity, amplitude and wavelength change as the beam propagates through tissue

A

true

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

axial resolution is determined chiefly by

A

pulse duration

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

benefits of harmonic imaging (2)

A
  • improve lateral resolution

- decrease grating lobes

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

what increases SPL?

A

n = number of cycles per pulse

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

increased bandwith improves what type of resolution

A

axial

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

For a linear array transducer consisting of a single row of elements, what method is most used to focus the beam in the elevational direction?

A

mechanical focusing

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

downfall to small footprint transducer

A

degrades resolution

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

sector display format that narrows to a point at the transducer surface. what transducer?

A

phased array

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

type of transduer that has the same measurement for elevational and lateral resolution

A

annular array

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

During the course of a sonographic exam, you notice lateral splaying of the echoes in the far field. What can you do to improve the image?

A

Increase the number of transmit focal zones and optimizes their location

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

You suspect that a bright spot on the B-mode image is a calcification, but a posterior acoustic shadow is not present. How can you best optimize your system to demonstrate a shadow distal to the calcification

A

Increase the transducer frequency

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

What is the purpose of the radiofrequency shield that is placed around the crystal and backing material of the ultrasound probe?

A

It reduces electromagnetic interference

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

What is the optimal thickness for the matching layer?

A

One-fourth of a wavelength

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

Parallel processing, define

A

A method used to improve frame rates with multizone electronic focusing is termed:

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

Which of the following best describes the f-number?

A

Focal length divided by the aperture

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

If you wish to perform a sonogram with the largest possible field of view in both the near field and at depth, what type of array transducer would be most preferable?

A

Curved array

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

how many cycles in a pulse with B-mode

A

1-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is purpose of applying multiple matching layers to the transducer face? (2)

A
  • decreases impedance

- increased bandwidth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the main advantage the stand-off pad provides to improve the image?

A

The stand-off pad increases the distance between the transducer and the mass, making it more likely that the mass will be located close to the elevational focus of

42
Q

If you are using a transducer with poor elevation resolution, which of the following problems are you most likely to encounter?

A

Inability to clearly demonstrate small cystic structures

43
Q

What can you do to improve contrast resolution in the ultrasound image?

A

Use a 2D or matrix array transducer

44
Q

Which represents the best measure of resolution for modern day ultrasound scanners?

A

Axial

45
Q

Which of the following transducer types is best suited to cardiac imaging?

A

Phased array

46
Q

tissue equivalent phantom measures (4)

A
  • axial resolution
  • contrast resolutino
  • lateral resolution
  • slice thickness
47
Q

You notice a loss of detail in the lateral dimension of the ultrasound image. What can you do to improve this?

A

increase scan line density

48
Q

What is the purpose of curving the transducer elements or applying a lens over the elements?

A

To provide focusing in the out-of-plane (elevational) direction

49
Q

What disadvantage and advantage is related to the use of a tightly curved array transducer?

A

advantage: field of view is improved
disadvantage: Lateral resolution degrades with depth

50
Q

In order to focus a sound beam relatively far away from the transducer, it is advantageous to:

A

Increase the diameter of the element

51
Q

increasing frame averaging aka persistence does what to frame rate

A

decreases

52
Q

The technique of frame averaging during real-time acquisition is designed to

A

Reduce random noise

53
Q

You are performing a sonographic examination and select the tissue harmonics operating mode. What advantage will you obtain over conventional imaging?

A

Improved contrast resolution

54
Q

What is a typical frame rate for B/mode real-time imaging?

A

10-50 Hz

55
Q

The term duty factor is defined as

A

The fraction of time the transducer is actively transmitting sound

56
Q

If you increase the pulse repetition frequency and leave all other controls unchanged, what will happen?

A

frame rate decreases

57
Q

What effect will you see in image if you increase the reject level?

A

Decreased low-level echoes

58
Q

If sound did not attenuate with increasing depth, what system control would you no longer need?

A

reject

59
Q

What system component determines the repetition frequency?

A

pulser

60
Q

What is the purpose of the preamplification of the incoming signal that occurs in the transducer assembly?

A

To increase echo voltages before noise is induced through the cable

61
Q

What function of the receiver converts electrical signals from radiofrequency to video form?

A

demodulation

62
Q

Which of the following best describes M-mode?

A

Depth of reflectors along a single line of sight vs time

63
Q

What information is present in the M-mode display? (3)

A

time, motion pattern, amplitude

64
Q

A digital scan converter is another name for what system component?

A

image memory

65
Q

Where are images stored in the ultrasound system?

A

scan converter

66
Q

The picture elements in a scan converter matrix are termed

A

pixels

67
Q

Digital to analog conversion of the ultrasound signal must occur at what part of the imaging process?

A

between the scan converter and the display

68
Q

when you “freeze’ the image, where is the echo information stored?

A

scan converter

69
Q

What is the order in which the signal travels in the ultrasound system?

A

Transducer, receiver, scan converter, display

70
Q

Of the following, which is the best choice to help you demonstrate tissue boundaries that are not perpendicular to the sound beam?

A

spatial compounding

71
Q

benefits of 3D imaging over 2D (2)

A
  • ability to display image planes impossible to obtain with 2D imaging
  • Ability to display orthogonal planes simultaneously
72
Q

You may observe a mirror image artifact with which imaging mode?

A

ALL OF THEM - b-mode, spectral, colour, power

73
Q

Which imaging technique may increase visualization of the reflections from blood flow on the real-time ultrasound image?

A

harmonics

74
Q

Which of the following artifacts commonly results in echoes filling in the lumen of small vessels?

A

partial volume

75
Q

Propagation speed error results in which sonographic appearance?

A

Improper axial position of an echo

76
Q

When you select harmonic imaging, which artifact is less likely to be observed?

A

Grating lobes

77
Q

When you select compound imaging, which artifact is less likely to be observed? (4)

A
  • refraction
  • -shadowing
  • enhancement
  • speckle
78
Q

what will decrease acoustic speckle in your image (2)

A
  • frame averaging

- compound

79
Q

If you wish to improve border definition, what imaging enhancement should you use?

A

spatial compounding

80
Q

What can you do to improve visualization of distal acoustic shadowing from calcification?

A

harmonics

81
Q

What helps to improve the axial resolution in a B-mode image?

A

increased bandwidth

82
Q

what helps to improve the lateral resolution in a B-mode image?

A

increased aperture

83
Q

what helps to improve the elevation resolution in a B-mode image?

A

Focusing with an acoustic lens

84
Q

What technique would be most likely to produce grating lobes in your image?

A

beam steering

85
Q

What term is used to describe a 3-dimensional pixel element in 3D sonography?

A

voxel

86
Q

What 2D limitation is addressed by 3D ultrasound imaging?

A

3D provides visibility of the coronal plane

87
Q

The packet size in color Doppler refers to the number of

A

Pulse/listen cycles per acoustic scan line

88
Q

A commonly used process for determining direction in a Doppler instrument is

A

Phase quadrature detection

89
Q

What method is used to steer the color beam with a linear array transducer?

A

What method is used to steer the color beam with a linear array transducer?

90
Q

What would be the most likely result from increasing the transmit frequency of the color Doppler?

A

Improved sensitivity to slow flow

91
Q

During Doppler interrogation of the carotid artery, you detect mirroring. Which of the following is a common cause of this artifact?

A

Doppler angle of interrogation near 90

92
Q

The rapid technique used in most color Doppler systems to obtain the mean doppler frequency shift is:

A

Autocorrelation

93
Q

packet size

A

number of pulses per scan line

94
Q

Color flash artifact obscuring the anatomy of interest in an exam of the abdominal aorta. What can you do to reduce impact of the flash?

A

Increase the wall filter

95
Q

You have increased the packet size while using color Doppler to evaluate flow. What position result will occur from this action?

A

Improved signal-to-noise ratio

96
Q

What two controls affect the spatial resolution of the color image?

A

frequency and line density

97
Q

Which condition is most likely to occur in patients having a normal arterial waveform shape, but low velocities across all vessels?

A

Low cardiac output

98
Q

Atherosclerosis begins within:

A

the intima

99
Q

String test objects are used to evaluate:

A

Doppler accuracy

100
Q

recommended ingredient in cleansers for intracavitary probes?

A

Glutaraldehyde

101
Q

You are using a transducer with poor elevation resolution. What problem will most likely be encountered as a result?

A

You will not be able to clear anechoic tubes oriented with their axis in the scan plane

102
Q

When measuring penetration on a tissue-mimicking phantom, how should the master gain and acoustic output be adjusted?

A

Maximum gain, maximum acoustic output

Physics REVIEW (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions