Digital Imaging Review

Front 1

Failure of the reader to find the collimation edges of an image

Back 1

May cause the image to be too bright or too dark

Front 2

If the entire range of exposure were digitized, pixel values representing ______ would be digitized.

Back 2

Scatter, diagnostic and extreme values

Front 3

Data collected within the collimator are represented by a

Back 3

Histogram

Front 4

A histogram displays the useful signal by locating

Back 4

Maximum and minimum signal

Front 5

The higher the kilovoltage peak, the

Back 5

Narrower the histogram

Front 6

True or False. The shape of the histogram is anatomy specific.

Back 6

True

Front 7

The Nyquist theorem states that

Back 7

The sampling frequency must be twice the input signal bandwidth

Front 8

If too few pixels are sampled, the result will be

Back 8

Low resolution

Front 9

Raw data used to form the image histogram are compared with

Back 9

A normal histogram referenced by the computer

Front 10

Loss of detail in a digitally processed image

Back 10

Occurs because of the number of conversions

Front 11

The longer an image is stored in the CR cassette, the

Back 11

More energy is lost by the electrons

Front 12

A wraparound image or image aliasing occurs when

Back 12

Sampling occurs less than twice per cycle

Front 13

True or False. Imaging aliasing is similar to moire effect caused by grid error.

Back 13

True

Front 14

In an effort to display the pixels for the area of interest when exposure is greater or less than what is needed to produce an image, ______ occurs.

Back 14

Automatic Rescaling

Front 15

Automatic resealing means that images are produced, regardless of the amount of exposure, with

Back 15

Uniform contrast and density

Front 16

True or False. Automatic resealing can be substituted for appropriate technical factors

Back 16

False

Front 17

A look up table is not used as a reference to

Back 17

Set appropriate kilovoltage peak and milliampere seconds values

Front 18

Changing the slope of the look up table graph will increase or decrease

Back 18

contrast

Front 19

The amount of error that can be made and still result in the capture of a quality image refers to

Back 19

latitude

Front 20

True or False. Exposure latitude for digital imaging is less than that of film/screen imaging.

Back 20

False. Digital has slightly greater exposure latitude.

Front 21

The Kodak process that allows increased latitude while preserving detail is known as

Back 21

EVP

Front 22

"The sum of the components in a recording system cannot be greater than the system as a whole" defines

Back 22

Modulation transfer function

Front 23

A perfect image processing system would have an MTF of

Back 23

100%

Front 24

True or False. It is possible to achieve an MTF of 100%.

Back 24

False

Front 25

The more light spread, the ______ the MTF.

Back 25

lower

Front 26

If all of the shades were left in an image after processing, the contrast would be

Back 26

Too low

Front 27

Changing the steepness of the exposure gradient

Back 27

Controls image contrast

Front 28

Focal spot and OID affect image sharpness

Back 28

In both film/screen and digital imaging

Front 29

The improper algorithm application may result in

Back 29

Repeat examinations and degradation of the image

Front 30

The more manipulation of the image, the greater the

Back 30

Loss of information

Front 31

Amplification of the frequencies of the areas of interest is known as

Back 31

Edge enhancement

Front 32

Suppressing frequencies in the areas of interest is known as

Back 32

masking

Front 33

Low pass filtering is also known as

Back 33

smoothing

Front 34

High pass filtering is useful for enhancing

Back 34

Organs and soft tissue

Front 35

Averaging the frequency of each pixel with surrounding pixel values to remove high-frequency noise is called

Back 35

Low pass filtering or smoothing

Front 36

Image level parameters control image

Back 36

Brightness, density

Front 37

The brightness or darkness of an image is controlled by

Back 37

level

Front 38

Excessive light entering the eye when viewing an image is known as

Back 38

Veil glare

Front 39

An image manipulation process that fills in the background so that it is darkened is known as

Back 39

shuttering

Front 40

True or False. Shuttering removes the dark exposed border, reducing the amount of information to be stored.

Back 40

False

Front 41

The image reader scans and reads the image from the

Back 41

Leading edge of the imaging plate to the opposite side

Front 42

The process of joining two or more images into one continuous image is known as image

Back 42

stitching

Front 43

The workstation function that allows selection of preset terms and/or manual text input is termed

Back 43

Image annotation

Front 44

Input of annotation for identification of the patient's left or right side

Back 44

Should be used in conjunction with the technologists markers

Front 45

Magnification of the entire image at the workstation is termed

Back 45

zoom

Front 46

Proper patient demographic input ensures

Back 46

Linking of all the patient's files

Front 47

The ability to send images to local network stations can be accomplished using the

Back 47

Manual send function

Front 48

True or False. Historical Study of patient examinations can be accomplished through the manual send function

Back 48

False

Front 49

Proper patient demographic input is the responsibility of the

Back 49

technologist

Front 50

True or False. No matter where the orientation stickers or labels exist on a digital cassette, the image will display correctly.

Back 50

False. It is displayed how its read, but we can turn in.

Front 51

Window Level

Back 51

Controls image brightness/density post processing, move the mouse vertical and horizontal

Front 52

Window Width

Back 52

Controls image contrast post processing, move the mouse down

Front 53

Density

Back 53

Brightness of monitor, directly controlled by mAs

Front 54

Contrast

Back 54

Different shades of gray, controlled by look up table in digital, controlled by kvp in film/screen

Front 55

Look up Table

Back 55

LUT, controls contrast, responsible for assigning values/ numbers to pixels in image

Front 56

Algorithm

Back 56

Mathematical formula used to construct histogram

Front 57

Histogram

Back 57

Graphical display of digital data

Front 58

Spatial Resolution (Spatial Frequency)

Back 58

Digitally recording data

Front 59

Smoothing can be applied to a digital image to mask

Back 59

Noise/quantum mottle

Front 60

Smoothing can also be called

Back 60

Low pass filtering or noise suppression tool

Front 61

Edge enhancement can be applied to a digital image to improve

Back 61

contrast

Front 62

What does Edge enhancement do

Back 62

improve visibility of small detail, controls contrast at edge of exam

Front 63

Applying to much edge enhancement has what effect on a digital image

Back 63

Halo Effect

Front 64

What happens when the post processing technique of equalization is applied to an image

Back 64

Equals out brightness/density

Front 65

Direct Digital vs. Indirect Digital

Back 65

DDR goes from x-ray to image, IDR goes from x-ray to light to image

Front 66

Algorithms determine the image

Back 66

Histogram

Front 67

If an image displays low contrast, what type of scale and latitude is this

Back 67

Long scale, wide latitude

Front 68

What is the problem with a technologist using post-processing techniques on an image and saving them and sending them to the Radiologist

Back 68

Once that is done, the images cannot be manipulated, limits the post processing for radiologist

Front 69

Preprocessing refers to

Back 69

Image correctness, anything prior to exam being preformed (raw data

Front 70

Who has control over preprocessing

Back 70

technologist selects, but computer software does the rest

Front 71

Post processing refers to

Back 71

Image refinement, Manipulating numbers on final image

Front 72

Who has control over post processing

Back 72

Technologist and Radiologist solely

Front 73

The look up table is primarily responsible for controlling

Back 73

contrast

Front 74

What effect does automatic rescaling have on an image

Back 74

Fixes technical errors

Front 75

Raw digital images have

Back 75

Low contrast

Front 76

What is the relationship between density and brightness on a display monitor vs density and brightness on a printed film

Back 76

On display monitor it is inversely related. When you increase brightness, density decreases. On printed film, it is proportional. When you increase brightness, density increases (gets darker)

Front 77

Image enhancement techniques or post processing techniques primarily affect what aspect of the digital image

Back 77

Spatial resolution

Front 78

Visibility of detail refers to

Back 78

Brightness (density) and contrast

Front 79

Visibility of sharpness or sharpness of detail refers to

Back 79

Spatial resolution and distortion

Front 80

What does the post processing technique of Subtraction do

Back 80

Removes superimposed structures

Front 81

What does the post processing technique of contrast enhancement do

Back 81

Enhances/equals out contrast on entire images (makes more uniform)

Front 82

What does the post processing technique of black/white reversal do

Back 82

Reverses gray scale

Front 83

Using too much of a post processing technique, can create _____ information on your image.

Back 83

false

Front 84

In digital subtraction, which image is usually used for the mask?

Back 84

First image right before the contrast is applied

Front 85

How is the moire effect made

Back 85

When grid lines and scanning frequency run parallel

Front 86

What can Aliasing cause

Back 86

Moire Effect because of Nyquist Theorem

Front 87

Direct Digital

Back 87

1 step process, increased dose, 0.5 mR exposure needed to make quality image, x-ray photons to electronic signal

Front 88

Indirect Digital

Back 88

2 step process, decrease patient dose (because light helps create electronic signal), 1.0 mR exposure needed to make quality image, x-ray photons to light to electronic signal

Front 89

When excess ________ is used noise can appear in low exposure areas and saturation in high exposure areas

Back 89

Equalization

Front 90

Contrast on monitor adjusted by

Back 90

Window width

Front 91

What is the advantage of digital over film screen

Back 91

More exposure latitude

Front 92

CR reader scans plates at what frequency

Back 92

2000 by 2000

Front 93

Image brightness on a display monitor is controlled by

Back 93

Window level

Front 94

What allows automatic rescaling numbers from histogram to proper contrast

Back 94

Look up table

Front 95

Dynamic Range

Back 95

number of shades of gray that can be shown.

Front 96

Amount of detail in a digital image

Back 96

Spatial resolution

Front 97

What could cause digital image to display low contrast

Back 97

Overexposure of imaging plate by 4 times

Front 98

Grid cutoff appears as

Back 98

Low contrast and quantum mottle

Front 99

Nyquist frequency refers to

Back 99

Sampling frequency of digital data

Front 100

Dirt on light guide of reader causes

Back 100

White lines

Front 101

The difference in image gray scale between closely adjacent regions on an image

Back 101

contrast

Front 102

Post processing technique primarily affects what aspect of an image

Back 102

resolution

Front 103

High contrast is ______ latitude

Back 103

narrow

Front 104

Wide dynamic range is ________ latitude

Back 104

wide

Front 105

Takes place in computer where software automatically functions to control what happens

Back 105

preprocessing

Front 106

Increasing Window level does what to the digital image

Back 106

Increase density

Front 107

Long scale contrast is

Back 107

Low contrast

Front 108

Highest spatial frequency that can be recorded by a digital detector by the DEL size is known as

Back 108

Nyquist Frequency

Front 109

Alters pixel values so they demonstrate different contrast levels

Back 109

Contrast enhancement

Front 110

4 steps to preprocessing

Back 110

1. Construct a histogram. 2. Automatic Rescaling. 3. Processing algorithms are used to formulate image reconstruction to specific type of exam preformed. 4. Algorithm determines final image histogram.

Front 111

Wide latitude, ______ shades of grays

Back 111

Lots

Front 112

Aliasing occurs when

Back 112

Spatial frequency is greater than the Nyquist frequency

Front 113

Wraparound image

Back 113

Image appears as two superimposed images slightly out of alignment (like a 3D movie without glasses)

Front 114

Gradient Processing looks at

Back 114

Density and contrast, puts color on image, gray scale (visibility of detail)

Front 115

Levels between minimum and maximum density is

Back 115

Contrast (the ranges are contrast)

Front 116

Increasing window width does what to contrast

Back 116

More shades of gray so its low contrast

Front 117

Decreasing window width does what to contrast

Back 117

Less shades of gray so its high contrast

Front 118

Pixel Depth/ Bit Depth

Back 118

Amount of shades of gray a pixel can demonstrate

Front 119

Wide latitude has ____ Shades of gray

Back 119

more

Front 120

In CR if exposure is more than _____ below ideal exposure, you will receive quantum mettle.

Back 120

50%

Front 121

If the exposure is more than ______ above ideal exposure, you will start receiving saturation and lose contrast

Back 121

200%

Front 122

Black and White reversal is used in

Back 122

Surgery situations to better visualize, PIC lines, fluoro, etc

Front 123

Window level controls

Back 123

How light and dark the image is

Front 124

Window Width controls

Back 124

Ratio of black to white