Deck 9: Image Quality and Characteristics

Question 1

What digital characteristics affects the number of shades of gray available for image display?

A) pixel size
B) pixel density
C) pixel pitch
D) pixel bit depth

Answer 1

pixel bit depth

Question 2

The overall quality of the radiographic image is determined by

A) sharpness
B) visibility of anatomic structures
C) accuracy of structural lines
D) all of these

Answer 2

all of these

Question 3

Which of the following refers to the absorption characteristics of the anatomic tissues radiographed and the quality of the x-ray beam?

A) brightness levels
B) subject contrast
C) grayscale
D) differential absorption

Answer 3

subject contrast

Question 4

Which of the following contribute to subject contrast?

A) Differences in tissue thickness.
B) Differences in tissue density.
C) Effective atomic number.
D) All of these.

Question 5

The ability of the imaging system to distinguish between small objects that attenuate the x-ray beam similarly is known as:

A) grayscale
B) spatial frequency
C) contrast resolution
D) brightness

Question 6

The control that adjusts the contrast by adjusting the visible range of brightness levels on the image is the

A) window level
B) window width
C) window pane
D) all of these

Question 7

Who evaluates the overall brightness on the image to determine if it is sufficient to visualize the anatomic area of interest?

A) Patient
B) Radiologist
C) Supervisor
D) Radiographer

Question 8

The amount of light emitted from the display monitor is

A) brightness
B) contrast resolution
C) spatial resolution
D) noise

Question 9

Visibility of the anatomic structures is accomplished by balancing
1) contrast
2) distortion
3) brightness

A) contrast and distortion only
B) contrast and brightness only
C) distortion and brightness only
D) contrast, distortion, and brightness

Question 10

Making the digital image appear with high contrast, more black and white, is done by

A) raising the window level
B) lowering the window level
C) increasing the window width (wide WW)
D) decreasing the window width (narrow WW)

Question 11

A radiographic image that has brightness levels that are very different from each other

A) has high contrast
B) has low contrast
C) has long-scale contrast
D) has low contrast and has long-scale contrast

Question 12

Making the digital image appear with low contrast, many shades of gray, is done by

A) raising the window level
B) lowering the window level
C) increasing the window width (wide WW)
D) decreasing the window width (narrow WW)

Question 13

A radiographic image that has brightness levels that are very similar to each other

A) has high contrast
B) has low contrast
C) has long-scale contrast
D) has low contrast and has long-scale contrast

Question 14

The midpoint of the range of brightness levels visible on the digital image is determined by

A) window level
B) window width
C) window pane
D) all of these

Question 15

What may happen when the digital image receptor is extremely over exposed?

A) excessive density
B) increased distortion
C) excessive contrast
D) saturation

Question 16

Radiographic contrast

A) produces sharper structural lines in the image
B) improves the magnification of the image
C) allows visibility of anatomic structures
D) produces sharper structural lines in the image and allows visibility of anatomic structures

Question 17

If there were no contrast, the radiographic image would include

A) only the same shade of gray
B) black and white
C) light gray and dark gray
D) black and light gray

Question 18

A radiographic image that is too light has ________________ to visualize the anatomic structures.

A) excessive brightness
B) excessive contrast
C) insufficient brightness
D) sufficient contrast

Question 19

What important feature provides a numeric value indicating the level of radiation exposure to the digital image receptor?

A) optical density
B) detective quantum efficiency
C) modulation transfer function
D) exposure indicator

Question 20

Which of the following is correct regarding the display feature windowing?

A) changing the window level will change the brightness level
B) increasing the window width will increase contrast
C) decreasing the window width will decrease contrast
D) changing the window level has no effect on the brightness level

Question 21

__________________ is a term used to evaluate accuracy of the anatomic structural lines recorded.

A) Contrast resolution
B) Spatial frequency
C) Spatial resolution
D) Detective quantum efficiency

Question 22

The radiographic misrepresentation of either the size (magnification) or the shape of the anatomic part is called

A) brightness
B) contrast
C) sharpness
D) distortion

Question 23

An increase in the image size of an object compared with its true, or actual, size, is called

A) size distortion
B) shape distortion
C) sharpness distortion
D) size distortion and sharpness distortion

Question 24

Objects that are being imaged can be misrepresented radiographically by distortion of their shape. This is called

A) size distortion
B) shape distortion
C) sharpness distortion
D) size distortion and sharpness distortion

Question 25

When the image of a structure appears shorter than the actual structure there is

A) size distortion
B) elongation
C) magnification
D) shape distortion

Question 26

Which of the following is correct regarding spatial frequency.
1) small objects have lower spatial frequency
2) small objects have higher spatial frequency
3) large objects have lower spatial frequency

A) small objects have lower spatial frequency and small objects have higher spatial frequency only
B) small objects have lower spatial frequency and large objects have lower spatial frequency only
C) small objects have higher spatial frequency and large objects have lower spatial frequency only
D) small objects have lower spatial frequency, small objects have higher spatial frequency, and large objects have lower spatial frequency

Question 27

The distance from the center of one pixel to the center of the one next to it is

A) grayscale
B) pixel pitch
C) pixel density
D) contrast resolution

Question 28

To measure resolution, a ______________ is necessary.

A) sensitometer
B) densitometer
C) resolution test pattern
D) resolution camera

Question 29

Which of the following combinations would result in an image with the least amount of magnification?

A) Decreased OID and decreased source-to-image receptor distance (SID).
B) Decreased OID and increased SID.
C) Increased OID and decreased SID.
D) Increased OID and increased SID.

Question 30

A line pair is made up of

A) a line
B) two lines
C) a space
D) a line and a space

Question 31

An imaging system that can resolve a greater number of line pairs within 1 mm is said to have ___________________.

A) improved spatial resolution
B) decreased spatial resolution
C) improved brightness
D) decreased brightness

Question 32

Increasing the matrix size for a fixed field of view (FOV) results in:

A) smaller pixel sizes
B) larger pixel sizes
C) increased spatial resolution
D) smaller pixel sizes and increased spatial resolution

Question 33

Resolution is typically measured in

A) line pairs per millimeter
B) line pairs per meter
C) line pairs per inch
D) line pairs per foot

Question 34

Spatial resolution can be increased by:
1) Increasing the pixel pitch
2) Increasing the pixel density
3) Decreasing the pixel pitch

A) Increasing the pixel pitch and increasing the pixel density only
B) Increasing the pixel pitch and decreasing the pixel pitch only
C) Increasing the pixel density and decreasing the pixel pitch only
D) Increasing the pixel pitch, increasing the pixel density, and decreasing the pixel pitch

Question 35

When the image of a structure appears longer than the actual structure, there is

A) size distortion
B) foreshortening
C) magnification
D) elongation

Question 36

The number of pixels per unit area is

A) grayscale
B) pixel pitch
C) pixel density
D) contrast resolution

Question 37

Size distortion is also called

A) elongation
B) magnification
C) shape distortion
D) foreshortening

Question 38

In order to minimize shape distortion in the image, what three factors should be properly aligned?
1) x-ray tube.
2) image receptor.
3) object-to-image distance.
4) anatomic part.

A) x-ray tube, image receptor, and object-to-image distance.
B) x-ray tube, object-to-image distance, and anatomic part.
C) image receptor, object-to-image distance, and anatomic part.
D) x-ray tube, image receptor, and anatomic part.

Question 39

What is a measure of the imaging system's ability to display the contrast of anatomic objects varying in size?

A) detective quantum efficiency
B) spatial resolution
C) spatial frequency
D) modulation transfer function

Question 40

Shape distortion is caused by

A) increasing the OID
B) angling the x-ray tube
C) angling the patient
D) angling the x-ray tube and angling the patient

Question 41

Distortion is misrepresentation of the size or shape of the anatomy being imaged.

Question 42

When the foot is placed directly on the image receptor, there is no OID.

Question 43

It is impossible to produce a radiographic image without unsharpness.

Question 44

Scatter radiation

A) is the result of photoelectric interactions
B) decreases the visibility of anatomic structures
C) results in higher radiographic contrast
D) is the result of photoelectric interactions and decreases the visibility of anatomic structures

Question 45

The higher the detective quantum efficiency (DQE) of a system, the lower the radiation exposure required to produce a quality image.

Question 46

Quantum noise is a result of

A) too few x-ray photons reaching the image receptor
B) too many x-ray photons reaching the image receptor
C) x-rays with energy that is too high reaching the image receptor
D) too few x-ray photons reaching the image receptor and x-rays with energy that is too high reaching the image receptor

Question 47

When the image is distorted, spatial resolution is also decreased.

Question 48

Which of the following will increase the ability to visualize anatomic tissues?
1) Increasing the contrast-to-noise ratio
2) Increasing the signal-to-noise ratio
3) A higher modulation transfer function

A) Increasing the contrast-to-noise ratio and increasing the signal-to-noise ratio only
B) Increasing the contrast-to-noise ratio and a higher modulation transfer function only
C) Increasing the signal-to-noise ratio and a higher modulation transfer function only
D) Increasing the contrast-to-noise ratio, increasing the signal-to-noise ratio, and a higher modulation transfer function

Question 49

Artifacts can make diagnosis of pathologic conditions difficult or impossible.

Question 50

Tissues that attenuate the x-ray beam very differently are said to be high subject contrast.

Question 51

With digital imaging, the intensity of radiation reaching the image receptor determines the brightness of the image.

Question 52

An artifact that is imaged within the patient's body is a

A) anatomic anomaly
B) foreign body
C) double exposure
D) none of these

Question 53

Decreasing the contrast-to-noise ratio will increase image quality.

Question 54

Scatter radiation is not a significant concern with digital imaging because the computer can adjust the image brightness and contrast.

Question 55

The radiographer should evaluate the exposure indicator value along with the quality of the digital image before determining whether a repeat image is warranted.

Question 56

Which of the following is a method of describing the strength of the radiation exposure compared with the amount of noise apparent in a digital image?

A) contrast-to-noise ratio
B) detective quantum efficiency
C) modulation transfer function
D) signal-to-noise ratio

Question 57

Brightness fluctuations on the image is called

A) brightness
B) contrast resolution
C) spatial resolution
D) quantum noise

Question 58

The resolution of the monitor used to display the digital image has an enormous effect on spatial resolution.

Question 59

Because it reduces spatial resolution, it is always best to minimize shape distortion in radiographic imaging.