Image Analysis

Question 1

A post-processing manipulation that can be added to digital projections as a means of helping the viewer to better evaluate contrast resolution in the selected area is a:

Answer 1

Contrast mask

Question 2

Additive disease processes that would require at least a 35% increase in mA include all of the following except:

Answer 2

Paget’s disease

Question 3

T/F: Using the smallest possible IR and covering at least 50% of it is a guideline for producing optimal image histograms

Answer 3

False

Question 4

All of the following are true about histogram analysis errors except:
a. histogram analysis errors result in erroneous exposure indicator numbers.
b. selecting the wrong body part or projection in the workstation menu will cause a histogram analysis error.
c. fog values outside the exposure field, but included in the VOI, do not cause widening of the histogram.
d. histogram analysis errors may occur as a result of poor central ray centering.

Answer 4

C

Question 5

All of the following are true about quantum noise except:
a. quantum noise is demonstrated as a blotchy appearance on the image.
b. quantum noise is visualized when the exposure indicator number is higher than the ideal exposure values.
c. quantum noise results in excessive patient dose when present on the image.
d. when present, quantum noise requires an increase in exposure factors to reduce its visualization on the image.

Answer 5

B

Question 6

All of the following are true about windowing except:
a. windowing is referred to as a post-processing manipulation procedure.
b. window level adjustments change the contrast of the image.
c. saving adjusted windowing settings to the PACS system narrows the dynamic range for future viewers.
d. windowing occurs after the image is displayed on the monitor.

Answer 6

B

Question 7

Best practice guidelines for the use of automatic exposure control include all of the following except:
1. set the optimum kV for the body part.
2. set the backup timer to 150% to 200% of the expected manual exposure.
3. set the highest mA station for the focal spot size needed.
4. wide collimation will ensure IR coverage.

Answer 7

4

Question 8

Examples of artifacts that must be accepted include all of the following except
1. pacemakers.
2. dental bridges.
3. pleural drainage tubes secured with safety pins.
4. endotracheal tubes.
5. heart monitoring lines.

Answer 8

3 and 5

Question 9

How many shades of gray can each pixel in a digital matrix display?

Answer 9

One

Question 10

The exposure indicator number represents all of the following except the:
a. measure of dose to the patient.
b. amount of exposure to the patient.
c. amount of light given off by the imaging plate.
d. amount of exposure to the imaging plate.

Answer 10

A

Question 11

What is the location on a histogram graph of fat?

Answer 11

Right

Question 12

What is the location on a histogram graph of bone?

Answer 12

Left

Question 13

Which technical factor listed below is primarily used to regulate density?

Answer 13

mAs

Question 14

Which of the following technical factors is primarily used to regulate subject contrast?

Answer 14

kVp

Question 15

Which of the following is true about image markers?
1. They are radiopaque.
2. They should be reversed before being placed on the IR.
3. They should be positioned as close to the median plane as possible.
4. They will be magnified if positioned on the imaging table or patient.

Answer 15

1 and 4

Question 16

Which of the following may occur as a result of the DI value greater than +3.0?
1. Excessive noise visible
2. Saturation
3. Patient overexposure

Answer 16

2 and 3

Question 17

T/F: A DI of −0.75 reflects insufficient exposure to the IR.

Answer 17

False

Question 18

T/F: The deviation index (DI) is a value that reflects the difference between the desired or target exposure to the IR and the actual exposure to the IR.

Answer 18

True

Question 19

Which of the following may impact the location and shape of the histogram?
1. Exposure technique
2. Positioning
3. Collimation

Answer 19

1, 2 and 3

Question 20

Which of the following is not a numerical value indicating the level of radiation exposure to a digital image receptor (IR)?

Answer 20

Window level

Question 21

What process is employed to maintain consistent digital image brightness for over- or underexposure?

Answer 21

Automatic rescaling

Question 22

Image artifacts can be caused by
1. dirty CR IPs.
2. low sampling frequency.
3. increased pixel density.

Answer 22

1 and 2

Question 23

T/F: Decreasing the displayed FOV for a given matrix size will decrease the size of the pixels and increase spatial resolution.

Answer 23

True

Question 24

T/F: A lower signal-to-noise ratio (SNR) improves the quality of a digital image.

Answer 24

False

Question 25

______ refers to the range of exposures that should be used to produce a diagnostic image.

Answer 25

Exposure latitude

Question 26

Small anatomic detail has:
A. decreased pixel density
B. increased spatial resolution
C. high spatial frequency
D. low signal to noise ratio

Answer 26

C

Question 27

Which of the following pixel bit depths would display a greater range of shades of gray to represent anatomic tissues?
A. 8 bit
B. 10 bit
C. 14 bit
D. 16 bit

Answer 27

D

Question 28

What is the process of assigning a numerical value to represent a brightness value?

Answer 28

quantization

Question 29

Which of the following would improve the spatial resolution of the digital image for a given field of view (FOV)?

A. A fixed matrix size and larger IP
B. A decreased sampling frequency and larger IP
C. A small matrix size and larger pixel size
D. A fixed matrix size and small IP

Answer 29

D

Question 30

Which of the following will improve the spatial resolution of the digital image?
A. Decreased sampling frequency and increased sampling pitch
B. Decreased sampling frequency and decreased sampling pitch
C. Increased sampling frequency and increased sampling pitch
D. Increased sampling frequency and decreased sampling pitch

Answer 30

D

Question 31

What is a measurement of the efficiency of an IR in converting the x-ray exposure it receives to a quality radiographic image?

Answer 31

DQE

Question 32

A higher sampling frequency during CR latent image digitization will:

Answer 32

Increase spatial resolution

Question 33

1. Which of the following would improve spatial resolution?
   A. Small matrix and large pixel size
   B. Decreased pixel density and increased pixel pitch
   C. Large matrix and large pixel size
   D. Large matrix and increased pixel density

Answer 33

D

Question 34

If the matrix size is increased for a fixed FOV:

Answer 34

the pixel size decreases

Question 35

Window and leveling changes the digital images:

Answer 35

Brightness and contrast

Question 36

What increases as matrix size increases?

Answer 36

Spatial resolution

Question 37

What digital process alters image brightness and grayscale to improve the visibility of anatomic structures?

Answer 37

LUTs

Question 38

T/F: Maintaining a low level of ambient lighting can improve soft-copy viewing of digital images.

Answer 38

True

Question 39

Display monitors used for soft-copy viewing of digital images should have __________.
A. increased ambient lighting
B. decreased matrix size
C. high pixel pitch
D. high luminance

Answer 39

D

Question 40

8. Which of the following is not a function during postprocessing of a displayed digital image?
   A. Histogram analysis
   B. Electronic masking
   C. Windowing
   D. Edge enhancement

Answer 40

A

Question 41

Wider window width __________.
A. increases brightness
B. decreases brightness
C. increases contrast
D. decreases contrast

Answer 41

D

Question 42

What postprocessing technique suppresses image noise?

Answer 42

Smoothing