Brainscape's Knowledge GenomeTM

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


See full index

Phys 254 > Artifacts *Pretty Important* > Flashcards

Artifacts *Pretty Important* Flashcards

1
Q

What is an artifact?

A

Anything that owes not correctly display the structures or functions that are imaged

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

Artifacts may be as simple as what?

A

A few echoes in a cystic structure that shouldn’t be there or as complex as duplication of a structure where only one truly exists

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

Artifacts can be the result or related to what four things?

A
  1. Malfunctions equipment
  2. Defective recording device
  3. Improper operation of equipment
  4. Acoustic properties of tissues and propagation of sound waves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Some artifacts can really useful in helping the sonographer to do what?

A

Diagnose or delineate structures like in the case of enhancement or shadowing

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

Some artifacts can be extremely confusing, what are a couple?

A

Some are extremely confusing like beam width artifact or refractive duplication

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

Many artifacts occur because assumptions are made about how sound propagates in tissue such as what four things?

A
  1. All tissues have the same acoustic velocity (1540 m/s)
  2. The sound beam always travels in a straight line
  3. Echo strength indicates organ echogenicity only
  4. The distance to each reflector equals the round trip time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Artifacts can be categorized as one of the following four things?

A
  1. Not real (not representing actual interfaces)
  2. Missing
  3. Improperly located
  4. Improper brightness, shape, or size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ultimately artifacts belong to one of 2 groups

A
  1. The propagation group
  2. The attenuation group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are some examples of propagation artifacts?

A
  1. Axial resolution
  2. Lateral resolution
  3. Section thickness
  4. Acoustic speckle
  5. Reverberation
  6. Mirror image
  7. Multiparty
  8. Refraction
  9. Grating and slide lobes
  10. Speed error
  11. Range ambiguity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When would we seen axial resolution artifacts?

A

When there are objects less than 1/2 the SPL apart in the axis of the bean are demonstrated as a single echo

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

What is artifacts in lateral resolutions? What is it referred to?

A

When the beam width artifacts that is also referred to as point spreading

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

What does point spreading look like?

A
  1. When reflectors appear smeared across the screen in areas where the beam is wide
  2. Can be accentuated with increased gain or TGC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How to correct for Point spreading? 3

A
  1. Lower the overall gain
  2. TGC adequately
  3. Scan in the near zone with a properly adjusted focus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is this image known as?

A

Image broadening

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

What does this image demonstrate?

A

Image broadening artifact

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

What is one way to effect the axial resolution artifact?

A

Use a higher frequency

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

What is an artifact seen in slice thickness? What is it known as?

A
  1. Sometimes known as volume averaging
  2. Can account for the filling in of an anechoic structure with false debris
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does slice thickness happen? What is the assumption?

A
  1. Under the assumption that all returning echoes come back from center of the beam
  2. There are echoes that form in front and behind the structure that are compressed into a 2D image
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do we account for volume average?

A

Repositioning the probe so that the narrowest portion of the Z- axis is at the desired location

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

What does this image demonstrate?

A

Slice thickness artifact

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

What does this image demonstrate?

A

Slice thickness

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

What is acoustic speckle a result of? 2

A
  1. Several off axis reflections from scatter reflection in the parenchyma
  2. Constructive and destructive interference occurs and creates heterogeneous brightness in the image
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does this image demonstrate?

A

Acoustic speckle

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

What is reverberation artifact? When do we normally see it?

A
  1. The reflection of sound between the transducer and a strong interface
  2. Often seen near the probe surface or in fluid filled structures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does reverberation look like?

A
  1. Multiple equally spaced linear lines that get weaker with depth
  2. Looks like rungs of a ladder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can account for reverberation?

A

Changing your window and using harmonics is the best way to eliminate the artifact

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

What is one way to tell the difference between section thickness artifacts and slice thickness artifacts?

A

Where is the focus?

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

What does this image demonstrate?

A

Reverberation

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

What does this image demonstrate?

A

Reverberation artifact

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

What artifact is shown by the yellow arrows?

A

Reverberation

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

What kind of artifact is comet tail?

A

A reverberation artifact

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

What is comet tail?

A

Specifically a short range reverberation between two very closely spaced Specular reflectors

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

What kind of objects results in reverberation?

A
  1. Metal clips
  2. Metal pellets
  3. Biopsy needle
  4. Metal IUCD
  5. Thin layers of things that cause comet tail
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Is comet tail useful?

A

It can be used to diagnose

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

What does this image demonstrate?

A

Comet tail

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

What does this image demonstrate?

A

Comet tail artifact. The IUCD is not as long, note the lengthening and the echogenicity of the IUCD

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

What kind of artifact is ring down?

A

Reverberation artifact

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

What does ring down artifact look like?

A

Similar to comet tail without the discrete echoes and instead appears as a continuous stream of long echoes

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

What is ring down artifact?

A

A resonance phenomena associated with gas bubbles in which gas vibrates and becomes a new source of sound

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

Is ring down useful?

A

Yes, just like comet tail this artifact can be useful for diagnosis

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

What does this image demonstrate?

A

Ring down artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What does this image demonstrate?

A

Ring down artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What does this image demonstrate?

A

Ring down artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is a mirror image artifact?

A

Artifact that results in a duplication of an object due to an odd angled strong reflector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How does this mirror image happen?

A

The machine assumes the beam is travelling in a straight line but when the beam is reflected by a Specular reflector towards the object and then returned to the probe along the same path

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What does this image demonstrate?

A

Mirror image artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What does this image demonstrate?

A

Mirror image artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What does this image demonstrate?

A

Mirror image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is the assumption for multiple atrifacts? Why is this a problem?

A
  1. This artifact is again the result of the assumption that beam travels in a straight line
  2. In reality the beam may take several off axis vectors before returning to the probe resulting in the incorrect location of the echoes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is the solution to correct for multiple artifacts?

A

Getting more perpendicular to the structure of interest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is a refractive artifact?

A

Refers to the direction of the beam when an interface is struck at the angle of both media have different velocities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are four different types of refractive artifacts?

A
  1. Edge shadowing
  2. Refractive duplication
  3. Refraction malposition
  4. Refractive enhancement
53
Q

What is edge shadow?

A

Shadows at the edges of strong curved reflectors because the beam changes direction with non-perpendicular incidence

54
Q

How do we correct for edge shadow?

A

Changing the window to come at the interface from a different angle

55
Q

What does this image demonstrate?

A

Edge shadows

56
Q

What does this image demonstrate?

A

Edge shadow

57
Q

What is refractive duplication?

A

Very confusing artifact that can create the appearance of lateral duplication of the echo interface on either side of its true location

58
Q

How does refractive duplication occur?

A
  1. Refraction of the beam by a strong interface
  2. Happens as the beam is swept, the lines of sight are angled
59
Q

What part of the body can seem like a refractive duplication?

A

Rectus abdominus

60
Q

One of the way to get account/ correct for refractive duplication?

A

Getting perpendicular to the structure of interest and move away from the cause

61
Q

What does this image demonstrate?

A

Refractive duplication

62
Q

What does this image demonstrate?

A

Refractive duplication

63
Q

What does this image demonstrate?

A

Refractive duplication

64
Q

What is refractive malposition?

A

When the interface is falsely allocated laterally from its true position and it in reality the echo is unlikely indenitifed or hidden

65
Q

What causes refractive malposition?

A

By the bending of the of the beam generating an echo which is falsely positioned along the beam axis

66
Q

What is the solution to correct for refractive malposition?

A

Getting perpendicular to the structure

67
Q

Is edge shadow helpful or hurtful?

A

Both. Because edge shadows show the edges, but at the same time it might block pathology.

68
Q

What are side lobes seen as? and what they are a result of?

A

Side lobes are seen as linear echogenic bands or sheets in anechoic structures and are the result of radial mode vibration in a single disc probe

69
Q

What are side lobe?

A

Echoes that return from weak side beams are laced along the axis of the main beam

70
Q

How do we account for side lobes?

A
  1. Insulator rings are used to suppress the radial mode vibrations
  2. TGC and gain manipulation to reduce the impact of this artifact
71
Q

What artifact does this image demonstrate?

A

Side lobe artifact

72
Q

How do grating lobes occur?

A

The length and width vibration of the array elements and crosstalk

73
Q

What does grating lobes look like?

A

A side lobe artifact but corrected with apodization and sub dicing

74
Q

How do we account for grating lobes?

A

Using harmonies to reduce or eliminate grating lobe artifacts

75
Q

What is the propagation speed error?

A

When the machines assumption of the propagation speed accounts for this artifact which results in the misallocation of reflectors proximal or distal to its actual position

76
Q

Where is propagation speed error commonly seen?

A

Occurs deep in fat

77
Q

Is there anyway to correct for the propagation speed error?

A

No

78
Q

What does this image demonstrate?

A

Propagation speed error

79
Q

What does this image demonstrate?

A

Propagation speed error

Look at the diaphragm

80
Q

What does this image demonstrate?

A

Propagation speed error

Look at the diaphragm

81
Q

What is occurrence rate for range ambiguity and what can it do?

A

This is rare in 2D scanning but can make echoes appear closer to the transducer then they actually are

82
Q

Where does range ambiguity occur?

A

Most commonly in doppler

83
Q

How does range ambiguity happen?

A
  1. It occurs when a pulse is emitted before all echoes from the previous pulse are received
  2. PRF is too high thereby exceeding the limit by the set depth
84
Q

How do we correct for range ambiguity?

A

Reduce the frame rate or PRF

85
Q

What does this image demonstrate?

A

Range Ambiguity

86
Q

What are attenuation artifacts and what does it include? 4

A

2nd group of artifacts and it includes:
1. Shawdowing
2. Enhancement
3. Focal Enhancement
4. Edge shadowing

87
Q

What does shadowing result in? Because of what the things?

A

Lack of echoes beneath a highly attenuating structure because of
1. Absorption of sound
2. Reflection of sound
3. Scattering of sound

88
Q

In terms of range ambiguity, for doppler our PRF can be seen as what?

A

Scale

89
Q

What does this image demonstrate?

A

Shadowing

90
Q

What does this image demonstrate?

A

Shadowing

91
Q

How is enhancement seen?

A

This is seen as posterior brightness to structures that attenuate less than surrounding structures (cyst or solid)

92
Q

Is shadows helpful or hurtful?

A

Both, it can help detect things like calcifications throwing shadows or it can hide things in shadows.

93
Q

When would we see an extremely rare occurrence of enhancement?

A

When a very homogenous medium causes enhancement

94
Q

Is enhancement a artifact that helps with diagnosis?

A

Yes

95
Q

What does this image demonstrate?

A

Posterior enhancement

96
Q

What is focal enhancement? What is it also known as?

A

False brightening to a particular area of the image at the level of the focal zone and is known as focal banding

97
Q

Why does focal enhancement occur?

A

The intensity of the sound is highest at this part of the beam

98
Q

How do we compensate for focal enhancement?

A

TGC

99
Q

What does this image demonstrate?

A

Focal enhancements

100
Q

What are some doppler artifacts?

A
  1. Aliasing
  2. Slice thickness
  3. Reverberation
  4. Mirror imaging
  5. Flash or clutter
  6. Noise
  7. Refraction
101
Q

Why is aliasing useful?

A

Aliasing in colour flow can be extremely helpful in identifying areas of higher velocity flows or turbulence which can be useful for diagnosing pathology

102
Q

What does this image demonstrate?

A

Aliasing

103
Q

What does this image demonstrate?

A

Aliasing

104
Q

What does this image below show?

A

Doppler slice thickness
Here velocities from multiple flows are seen within one flow envelope because of the beam width phenomenon

105
Q

What is Doppler reverberation similar to?

A

Reverberation on 2D scans and is seen as a buzzing or equidistant colour lines

106
Q

What is twinkle artifact? What is its effective in diagnosing?

A

A type of reverberation which is helpful to aid in diagnosing calculus

107
Q

The reverberation between the front and back wall of a stone will produce what during doppler?

A

A mosaic of colour deep to the stone

108
Q

What does this image demonstrate?

A

Doppler reverberation

109
Q

What do these images demonstrate?

A

Doppler reverberation

110
Q

Does mirror imaging effect both colour and spectral tracing?

A

Yes

111
Q

Spectral mirror has ____________ on both sides of the ____________ and is caused by what?

A
  1. Doppler flow
  2. Baseline
  3. Having an angle of incidence too close to 90 degrees
112
Q

With colour doppler what will appear deep to real one?

A

A false vessel will appear deep to the real one

113
Q

What does this image demonstrate?

A

Doppler mirror image

look at the spectral, there is no noise. This is how we know that we aren’t over gained but to perpendicular

114
Q

What does this image demonstrate?

A

Doppler mirror image

115
Q

How does doppler flash or clutter appear?

A

It appears as low level echoes in the colour flow seen in the tissue as the result of tissue movement like the heart wall, valve or vessel wall motion for example

116
Q

What is available to help with doppler flash or clutter?

A

Filter presents within the machine to help eliminate this motion as their velocities are usually lower then the flowing blood

117
Q

What is the disadvantages of setting our filters too high?

A

There is a risk of eliminating real flow information

118
Q

What does this image demonstrate?

A

Doppler flash and clutter

119
Q

When does doppler noise happen?

A

When doppler gains are set too high causing the colour to blossom outside the vessel or appear in anechoic structures that have no flow

120
Q

With spectral, the over gaining can do what in terms of doppler noise?

A
  1. Increase the peak systolic velocities which can impact the diagnosis
  2. It can also cause a halo effect that could result in the overestimation of velocity
121
Q

What does this image demonstrate?

A

Doppler noise

The black area, is the doppler noise

122
Q

What does this image demonstrate?

A

Doppler noise artifacts when the cystic lesions with the gain set too high

123
Q

There are other reasons why you may get artifacts while scanning related to malfunction of equipment what are they?

A
  1. Electronic interference
  2. Fault software
  3. Faulty scan converter
  4. Faulty equipment
124
Q

What is electronic interference? What does it look like?

A
  1. At times you may see an echo pattern either of low/high intensity that can be regular/ irregular
  2. This is usually radio frequency signals generated by other equipment that interfere with the ultrasound wave
125
Q

What does this image demonstrate?

A

Electronic interference

look at all the whispy things

126
Q

What is the 60 Hz bandwidth?

A

When radio frequency signal generated by other equipment that interfere with the ultrasound wave

127
Q

What does this image demonstrate?

A

The 60 Hz bandwidth

look at the faint bandwidth artifact

128
Q

Any one of the following things may also change the appearance of the image to something that is not real such as what?

A
  1. Malfunctioning crystal element
  2. Cracked damping material
  3. Defective recording device
  4. Improper transducer shielding
129
Q

What does the arrows point to from left to right?

A

Dead elements and weak/dead elements

Phys 254 (19 decks)

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