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Vascular II & Physics II > Physics Ch. 15 & 16 > Flashcards

Physics Ch. 15 & 16 Flashcards

1
Q

Composed of 2 shades, black and white

A

bistable images

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2
Q

Gray scale displays multiple

A

levels of brightness: white, black and gray

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3
Q

What are the two display user controls for video monitors

A

contrast, brightness

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4
Q

Determines range of brilliancies within displayed image

A

contrast

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5
Q

Bistable images are _____ contrast

A

high

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6
Q

Gray scale images are _____ contrast

A

low

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7
Q

Determines brilliance of the displayed image

A

brightness

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8
Q

Store information and display it

A

scan converter

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9
Q

Used in early days of two-dimensional imaging

A

analog scan converter

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10
Q

Used in modern day A-D imaging

A

digital scan converter

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11
Q

Can have an unlimited and continuous range of values

A

analog numbers

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12
Q

Discrete values

A

Digital numbers

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13
Q

Spatial resolution (imaging detail) of an analog scan converter is

A

excellent

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14
Q

Limitation of analog scan converter

A

image fade, image flicker, instability, deterioration

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15
Q

Use computer technology to convert images into numbers

A

digitizing (1s and 0s)

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16
Q

Advantages of digital scan converters

A

uniformity, stability, durability, speed, accuracy

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17
Q

Two important elements of digital scan converters

A

pixel, bit

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18
Q

Picture element, smallest building block of a digital picture

A

pixel

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19
Q

Number of pixels per inch

A

pixel density

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20
Q

Higher pixel density is achieved with

A

smaller pixels (more pixels per inch)

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21
Q

What improves with high pixel density and creates an image with greater detail

A

spatial resolution

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22
Q

Binary digit, smallest amount of computer memory, bistable

A

bit

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23
Q

Group of bits and a series of 0s and 1s, digital

A

binary number

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24
Q

A group of 8 bits of computer memory

A

byte

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25
Q

Computer memory that consists of 2 bytes

A

word

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26
Q

Many shades of gray have better

A

contrast resolution

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27
Q

How many shades of gray are displayed with 5 bits of memory

A

32

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28
Q

Converting information from analog to digital is advantageous because

A

digital information is far less susceptible to contamination

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29
Q

What is the 5 step process from analog to digital

A
  1. A-to-D converter, 2. preprocessing, 3. post processing, 4. D-to-A converter, 5. Analog form is displayed
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30
Q

Manipulation of image data BEFORE storage in the scan converter

A

pre processing

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31
Q

Can preprocessing be reversed

A

no

32
Q

Manipulation of image data AFTER storage in the scan converter

A

post processing

33
Q

Can post processing be reversed

A

yes

34
Q

Sonographer can improve visualization of anatomic detail by enlarging a portion of an image to fill the enter screen

A

magnification/zoom

35
Q

What are the 2 types of magnification

A

read, write

36
Q

Which magnification occurs in postprocessing? Preprocessing?

A

read, write

37
Q

In read, the number of pixels in the magnified image is _____ as the original

A

the same

38
Q

In read, spatial resolution _______ because the number of pixels are _______

A

does not change, unchanged

39
Q

In write, the number of pixels in the magnified image is ______ that that of the ______

A

greater than, original

40
Q

In write, spatial resolution is ______ as there is an _____ number of pixels

A

improved, increased

41
Q

Method of improving image quality. Developed within context of bioeffects

A

coded excitation

42
Q

Creates very long pulses containing a wide range of frequencies

A

coded excitation

43
Q

Coded excitation occurs in the

A

pulser

44
Q

Advantages of coded excitation

A
  1. higher signal to noise ratio, 2. improved axial res, 3. improved spatial res, 4. improved contrast res, 5. deeper penetration
45
Q

Method of using sonographic information from different imaging angles to produce a single image

A

spatial compounding

46
Q

Is spatial compounding pre or post processing

A

pre

47
Q

Reduces speckle and minimizes shadowing artifact

A

compound images

48
Q

Do compound images improve spatial resolution? Temporal resolution?

A

yes, no

49
Q

______ steering of the sound beam is used in compound imaging

A

electronic

50
Q

Advanced technique that reduces speckle artifact and noise in the ultrasound images

A

frequency compounding

51
Q

Preprocessing method that makes pictures look sharper

A

edge enhancement

52
Q

Occurs in preprocessing, commonly known as persistence, processing technique that continues to display information from older images

A

temporal compounding, persistence, temporal averaging

53
Q

Temporal compounding/persistence creates a _____ image with ______ noise, ______ signal to noise ratio and _____ image quality. It ______ temporal resolution

A

smoother, reduced, higher, improved, reduces

54
Q

With sector shaped images, the scan lines separate at increasing depths. Gaps or missing information exists between the scan lines and this interprets it

A

fill-in interpolation

55
Q

Fill-in interpolation ______ spatial resolution and is a form of _________

A

improves, pre processing

56
Q

Images are related to mechanical properties of the tissue, will deform differently following the application of a force, stiffness data

A

elastography

57
Q

Elastography ________ spatial resolution

A

does not improve

58
Q

What does PACS stand for

A

picture archiving and communications system

59
Q

Describes the digital ultrasound lab in which images and additional medical information are digitized and stored on a larger computer network

A

PACS

60
Q

What does DICOM stand for

A

Digital Imaging and Computers in Medicine

61
Q

Set of rules and protocols that allows imaging systems to share information on a network

A

DICOM

62
Q

Method of describing the extent to which a signal can ary and still maintain accuracy

A

dynamic range

63
Q

Units of dynamic range

A

dB

64
Q

Comparison ratio between the largest and smallest signal that are measured accurately

A

dynamic range

65
Q

As a general rule, the dynamic range of information _____ the more it is processed

A

decreases

66
Q

Eliminates the potential errors when moving from on component to another

A

compression of dynamic range

67
Q

If an image has high contrast, it has ____ shades of gray

A

few

68
Q

Represents the level below which information will not be displayed

A

threshold

69
Q

A _____ pixel density improves spatial resolution

A

high

70
Q

Are the following procedures usually pre or post processing? Modifying a frozen image, read zoom, write zoom, adjusting brightness on the monitor, increasing the receiver gain

A

post, post, pre, post, pre

71
Q

With frequency compounding, how many pulses are transmitted down each scan line

A

1

72
Q

An uncompressed image signal within the receiver of an ultrasound system has a dynamic range of 110dB. The signal undergoes 40dB of compression. What is the dynamic range of the compressed signal?

A

70dB

73
Q

An uncompressed signal has a dynamic range of 85dB. The signal undergoes 30dB of compression. What is the dynamic range of the compressed signal

A

55dB

74
Q

After compression, a signal within the ultrasound system has a dynamic range of 70dB. The original signal was compressed by 40dB. What is the dynamic range of the original, uncompressed signal

A

110dB

75
Q

A signal within a system’s receiver has a dynamic range of 60dB after compression. The original signal was compressed by 50dB. What is the dynamic range of the original, uncompressed signal

A

110dB

76
Q

Narrow dynamic range has ____ contrast

A

high

77
Q

Wide dynamic range has _____ contrast

A

low

Vascular II & Physics II (21 decks)

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