4) Image Display
1. The DICOM Grayscale Standard Display Function (GSDF) uses principles derived from Barten's characterization of which property of the human visual system?
A) spatial resolution
B) uneven distribution of rods and cones in the retina
C) contrast sensitivity
D) color vision
E) all of the above
F) a and c
Answer:
C) contrast sensitivity
2. A purpose of calibrating a display is to:
A) Keep the luminance stable
B) Increase the perceived contrast resolution
C) Avoid artifacts
D) Provide consistent image presentation
E) a and d
F) b and d
Answer:
F) b and d
3. For optimal viewing in the digital reading room, ambient room lights should be:
A) 0 – 20 lux
B) 20- 40 lux
C) 40 – 60 lux
D) turned off completely
Answer:
B) 20- 40 lux
4. The 20-20-20 rule
A) limits noise amplification in image processing
B) refers to an easy way to reduce eye fatigue
C) shorthand for the ACR control limits for white-level, black-level and ambient lighting
D) is the time from acquisition to completion to finalization of an examination
Answer:
B) refers to an easy way to reduce eye fatigue (every 20 minutes look at something 20 feet away for 20 seconds)
5. CAD is most effective
A) for expert readers
B) at identifying true negatives
C) at increasing detection efficiency
D) both a and c
Answer:
C) at increasing detection efficiency (its more effective for inexperienced readers than expert readers)
6. CADe and CADx are computer-aided schemes designed respectively to:
A) segment and delineate lesions
B) pre-process and extract lesions
C) measure and define lesions
D) detect and classify lesions
Answer:
D) detect and classify lesions
7. Manufacturers typically describe the viewing angle of a display by the angle at which contrast is ___________ of on-axis viewing.
A) 90%
B) 60%
C) 40%
D) 10%
Answer:
D) 10%
8. Medical grade displays for radiology typically vary from consumer grade displays in which characteristics?
A) luminance stabilization
B) LCD panel (IPS vs PVA)
C) Viewing angle
D) DICOM calibration
E) All of the above
F) b and d
Answer:
E) All of the above
9. An iPhone would be a suitable platform for reading MSK digital radiographic images
A) True
B) False
Answer:
B) False
10. LCDs work by:
A) Pixels of a TFT arrays signal liquid crystals to rotate the polarization of light. Polarizing filters preferentially absorb light which isn’t polarized along its axis.
B) Pixels of a TFT arrays signal liquid crystals to shift the frequency (color) of the light, and different color filters absorb different colors of light.
C) Pixels of a TFT arrays trigger lights to turn on and off in different places on the display.
Answer:
A) Pixels of a TFT arrays signal liquid crystals to rotate the polarization of light. Polarizing filters preferentially absorb light which isn’t polarized along its axis.
11. According to the ACR, the maximum luminance for a primary display (other than for mammography) should be
A) 200 times the black-level
B) In a comfortable range for the radiologist
C) greater than 171 cd/m2
D) stable
Answer:
C) greater than 171 cd/m2
12. According to the ACR, a display used primary viewing should account for no more than __________of the image noise.
A) 1/2
B) 1/3
C) 1/10
D) 1/20
Answer:
B) 1/3
13. The primary intent of medical image processing is to:
A) Quantify specific image characteristics
B) Modify the optical characteristics of the image in order to enhance the estimation of specific physical parameters of the image subject
C) provide images to patients to take with them
D) All of the above
Answer:
B) Modify the optical characteristics of the image in order to enhance the estimation of specific physical parameters of the image subject
14. The use of virtual endoscopy:
A) Gives the ability to fly through human hollow structures non-invasively
B) can provide biopsy specimens from specific tissues
C) Needs extensive computer skills to perform
D) All of the above
Answer:
A) Gives the ability to fly through human hollow structures non-invasively
15. It is best to view images on a display that:
A) Is as large as space and budget permit
B) Is portable
C) Can either match the matrix size of your image or provide efficient access to the full resolution image
D) Is made by the same manufacturer as the workstation.
Answer:
C) Can either match the matrix size of your image or provide efficient access to the full resolution image
16. The three types of motion for tomosythesis systems are:
A) parallel, sequential, partial isocentric
B) parallax, partial isocentric, full isocentric
C) parallel, partial isometric, full isometric
D) parallel, partial isocentric, full isocentric
Answer:
D) parallel, partial isocentric, full isocentric
17. One of the main goals of tomosynthesis is to:
A) reduce the amount of overlapping anatomic structure in a given plane
B) reduce the dose to the patient
C) increase the dose to the pastient
D) increase image blur
Answer:
A) reduce the amount of overlapping anatomic structure in a given plane
18. The Quality Control (QC) workstation
A) is used by the radiologist for primary diagnoses
B) allows the technologist to see how the images should appear to the radiologist
C) allows the patient to view their images
D) used by medical physicists to calibrate diagnostic displays
Answer:
B) allows the technologist to see how the images should appear to the radiologist
19. The contrast ratio of a display is
A) the ratio of maximum luminance, or white-level, to minimum luminance, or black-level
B) the proportion of black pixels compared to white pixels
C) not related to image quality
D) cannot be adjusted by the user
Answer:
A) the ratio of maximum luminance, or white-level, to minimum luminance, or black-level
20. The three main variables optimized in tomosynthesis acquisition are:
A) patient size, patient weight, patient height
B) number of projected images, number of tubes, number of detectors
C) dose, exposure, DQE
D) number of projection images, total angle of tube movement, and number of reconstructed planes
Answer:
D) number of projection images, total angle of tube movement, and number of reconstructed planes