MIC Ch8 CT Artifacts

Card Set Information

Author:
sully79
ID:
308465
Filename:
MIC Ch8 CT Artifacts
Updated:
2015-09-24 14:04:55
Tags:
MIC CT Registry Review Artifacts
Folders:

Description:
CT Artifacts
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user sully79 on FreezingBlue Flashcards. What would you like to do?


  1. 28. Which of the following may reduce the out-of-field artifact?
    A. increasing the scan field-of-view
    B. reducing the slice thickness
    C. increasing the matrix
    D. reducing the reconstruction field-of-view
    A. increasing the scan field-of-view
    (this multiple choice question has been scrambled)
  2. 8. A cone beam artifact may look like stars:
    A. at the center of the image
    B. coming from structures around the edge of the image
    C. coming from con-shaped structures
    D. from all structures with high CT numbers
    B. coming from structures around the edge of the image
    (this multiple choice question has been scrambled)
  3. 36. Which of the following affects beam hardening?
    1. the types of tissues the beam passes through
    2. the thickness of the tissues traversed by the beam
    3. the energies of the photons in the beam
    A. 1, 2 and 3
    B. 3 only
    C. 1 only
    D. 2 only
    A. 1, 2 and 3
    (this multiple choice question has been scrambled)
  4. 10. A CT artifact is:
    A. a parameter used to control the brightness of the image
    B. always a reason to call for repair of the CT scanner
    C. used to time the injection of contrast media
    D. an anomaly in the CT image
    D. an anomaly in the CT image
    (this multiple choice question has been scrambled)
  5. 16. Which of the following would desplay the greatest amount of partial volume artifact?
    A. a 5 mm slice from a 20 slice study
    B. a 10 mm slice from a 20 slice study
    C. a 5 mm slice from a 40 slice study
    D. a, b and c would experience the same amount of partial volume artifact
    B. a 10 mm slice from a 20 slice study
    (this multiple choice question has been scrambled)
  6. 29. Which of the following is a result of reducing the slick thickness to reduce partial volume effects?
    1. increased appearance of noise
    2. increased spatial resolution
    3. decreased anatomical coverage with the same number of slices
    A. 2 only
    B. 1, 2 and 3
    C. 1 only
    D. 3 only
    B. 1, 2 and 3
    (this multiple choice question has been scrambled)
  7. 20. Which of the following is a possible manifestation of beam hardening?
    1. CT number inaccuracies
    2. streaks in the image
    3. cupping artifact
    A. 3 only
    B. 1 only
    C. 2 only
    D. 1, 2 and 3
    D. 1, 2 and 3
    (this multiple choice question has been scrambled)
  8. 38. Which of the following would result if the filter at the aperture of the x-ray tube removed even more low energy x-ray photons?
    A. partial volume artifact would decrease
    B. beam hardening artifact would increase
    C. beam hardening artifact would decrease
    D. partial volume artifact would increase
    C. beam hardening artifact would decrease
    (this multiple choice question has been scrambled)
  9. 21. What is the cause for the cupping artifact?
    A. the tissues of the body attenuate low energy photons
    B. the central tissues are not penetrated by the x-ray beam
    C. the interface between tissues with different densities causes the high energy photons to be absorbed
    D. the mean energy of the photons that comprise the x-ray beam is lowered
    A. the tissues of the body attenuate low energy photons
    (this multiple choice question has been scrambled)
  10. 13. Which of the following would make noise in the image appear less noticeable?
    1. increased window widths
    2. increased mAs
    3. increased slice thickness
    A. 1 only
    B. 3 only
    C. 2 only
    D. 1, 2 and 3
    D. 1, 2 and 3
    (this multiple choice question has been scrambled)
  11. 22. Which of the following may be the cause of two parallel lines seen on a localizer image?
    A. a problem with the reconstruction algorithm
    B. cone beam artifact
    C. two faulty detector elements
    D. tube arcing
    C. two faulty detector elements
    (this multiple choice question has been scrambled)
  12. 30. How would we expect metal to affect the appearance of a localizer image?
    A. the metal object will be represented by high CT numbers and there will be no streaks
    B. the CT numbers of the tissues in the image will be misrepresented
    C. the entire image will appear blurry
    D. streaks will emenate from the metal object in the image
    A. the metal object will be represented by high CT numbers and there will be no streaks
    (this multiple choice question has been scrambled)
  13. 40. Why must we choose a scan field-of-view which is larger than the anatomy to be scanned?
    1. to achieve the highest spatial resolution
    2. to minimize partial volume artifacts
    3. to avoid out-of-field artifacts
    A. 1 only
    B. 3 only
    C. 2 only
    D. 1, 2 and 3
    B. 3 only
    (this multiple choice question has been scrambled)
  14. 32. Which of the following may be the cause of a metal artifact?
    1. earrings
    2. a zipper
    3. dental fillings
    A. 1, 2 and 3
    B. 3 only
    C. 1 only
    D. 2 only
    A. 1, 2 and 3
    (this multiple choice question has been scrambled)
  15. 11. Beam hardening refers to:
    1. the increase in the number of photons reaching the detectors
    2. the increase in the number of low energy photons reaching the detectors
    3. the increase in the average energy of the photons that reach the detectors
    A. 1 and 3
    B. 2 only
    C. 3 only
    D. 1 only
    C. 3 only
    (this multiple choice question has been scrambled)
  16. 37. Which of the following might increase the possibility of motion artifacts occuring?
    A. immobilizing the patient
    B. using a helical scanning technique to acquire the necessary slices in a single breath-hold (assuming the patient can refrain from breathing for the required time)
    C. using no straps or pads so that the patient feels comfortable and unrestricted
    D. explaining the procedure to the patient
    C. using no straps or pads so that the patient feels comfortable and unrestricted
    (this multiple choice question has been scrambled)
  17. 31. What is the cause of cone beam artifacts?
    A. hardening of the x-ray beam on multi-row detector scanners
    B. inefficient x-ray tubes used on multi-row detector scanners
    C. faulty detector elements
    D. the use of a standard filtered back projection reconstruction when the x-ray beam is more than 20 mm thick
    D. the use of a standard filtered back projection reconstruction when the x-ray beam is more than 20 mm thick
    (this multiple choice question has been scrambled)
  18. 23. Which of the following would reduce the partial volume effect?
    A. decreased matrix
    B. decreased slice thickness
    C. increased mAs
    D. increased reconstruction field-of-view
    B. decreased slice thickness
    (this multiple choice question has been scrambled)
  19. 19. Which of the following would increase the severity of the edge gradient effect?
    1. a scanner with a small detector aperture
    2. a scanner with a low data sampling rate
    3. using thin slices
    A. 2 only
    B. 1, 2, and 3
    C. 1 only
    D. 3 only
    A. 2 only
    (this multiple choice question has been scrambled)
  20. 1. Which of the following affects the severity of metal artifacts?
    1. the quantity, composition and shape of the metal
    2. the slice thickness
    3. the number of data sampling points
    A. 3 only
    B. 1 only
    C. 1, 2 and 3
    D. 2 only
    C. 1, 2 and 3
    (this multiple choice question has been scrambled)
  21. 18. Which of the following would eliminate a ring artifact?
    A. decreased matrix
    B. removal of metal
    C. increased mAs
    D. recalibration of the detector elements
    D. recalibration of the detector elements
    (this multiple choice question has been scrambled)
  22. 6. _____ in the image is a possible manifestation of patient motion
    1. Ghosting
    2. Blurring
    3. Streaks
    A. 1 only
    B. 1, 2 and 3
    C. 3 only
    D. 2 only
    B. 1, 2 and 3
    (this multiple choice question has been scrambled)
  23. 4. CT x-ray tue arcing can occur because of _____ the x-ray tube.
    1. impurities in the oil outside
    2. tungsten gas inside
    3. tungsten solids in the oil inside
    A. 2 and 3
    B. 2 only
    C. 1 only
    D. 1 and 2
    D. 1 and 2
    (this multiple choice question has been scrambled)
  24. If an algorithm to correct for the cupping artifact is applied too aggressively to the data for a head image, the _____ of the image would be too bright.
    1. top and bottom
    2. center
    3. edges
    A. 3 only
    B. 2 only
    C. 1 only
    D. 1 and 3
    B. 2 only
    (this multiple choice question has been scrambled)
  25. 2. Which of the following may occur if the patient's arms are placed at their sides during a chest exam if the scan field-of-view is 33 cm?
    1. beam hardening
    2. out-of-field artifact
    3. cone beam artifact
    A. 1 and 2
    B. 3 only
    C. 1 only
    D. 2 only
    A. 1 and 2
    (this multiple choice question has been scrambled)
  26. 12. Which of the following could allow for a reduction of partial volume artifact while not increasing the appearance of the noise in the image?
    A. decreasing slice thickness while increasing mAs
    B. decreasing slice thickness while decreasing mAs
    C. increasing slice thickness while increasing mAs
    D. increasing slice thickness while decreasing kVp
    A. decreasing slice thickness while increasing mAs
    (this multiple choice question has been scrambled)
  27. 9. A variation in which of the following will affect the hardening of an x-ray beam?
    1. tissue density
    2. tissue thickness
    3. kVp
    A. 1 only
    B. 2 only
    C. 3 only
    D. 1, 2 and 3
    D. 1, 2 and 3
    (this multiple choice question has been scrambled)
  28. 26. In which direction are streaks from the edge gradient effect oriented?
    A. parallel to the direction of the sharp density defference interface
    B. in a herringbone pattern across the image
    C. radially outward from the center of the image
    D. perpendicular to the direction of the sharp density difference interface
    A. parallel to the direction of the sharp density defference interface
    (this multiple choice question has been scrambled)
  29. 7. On a CT image of the brain a cupping artifact would appear brighter:
    A. at the periphery of the brain
    B. immediately around dense structures
    C. at the anterior and posterior aspects of the brain
    D. in the center of the brain
    A. at the periphery of the brain
    (this multiple choice question has been scrambled)
  30. 33. Which of the following may be a result of partial volume averaging?
    1. decreased sharpness of edges
    2. inaccurate CT numbers
    3. ghosting of tissue boundaries
    A. 1 only
    B. 2 only
    C. 1 and 2
    D. 3 only
    C. 1 and 2
    (this multiple choice question has been scrambled)
  31. 14. The service engineer should be notified about which of the following?
    1. frequent bad streaks on the inferior slices of head scans
    2. a consistent circle on the images
    3. frequent bad streaks throughout the entire image
    A. 2 only
    B. 3 only
    C. 2 and 3
    D. 1 only
    C. 2 and 3
    (this multiple choice question has been scrambled)
  32. 35. How would the artifact from a faulty detector element appear on a localizer image?
    A. a circle in the center of the image
    B. a line parallel to the long axis of the patient table
    C. it depends on the orientation in which the localizer image is performed
    D. a line perpendicular to the long axis of the patient table
    B. a line parallel to the long axis of the patient table
    (this multiple choice question has been scrambled)
  33. 39. Which of the following is TRUE as the slice thickness is decreased?
    A. partial volume artifacts and edge gradient artifacts decrease
    B. partial volume artifacts and edgte gradient artifacts increase
    C. partial volume artifacts increase while edge gradient artifacts decrease
    D. partial volume artifacts decrease while edge gradient artifacts increase
    A. partial volume artifacts and edge gradient artifacts decrease
    (this multiple choice question has been scrambled)
  34. 25. A(n) _____ artifact is a streak artifact which arises from a high spatial frequency interface between tissues with a great diference in density.
    A. ring
    B. edge gradient
    C. tube arcing
    D. cone beam
    B. edge gradient
    (this multiple choice question has been scrambled)
  35. 24. Which of the following would decrease the effects of beam hardening artifacts?
    1. increased kVp
    2. increased mAs
    3. increased scan time
    A. 2 only
    B. 1 only
    C. 1 and 2
    D. 3 only
    B. 1 only
    (this multiple choice question has been scrambled)
  36. 27. Which of the following strategies would NOT help us differentiate possible pathology from a partial volume artifact?
    1. inspection of adjacent slices
    2. collect additional thinner slices through suspicious region
    3. rescan and decrease pitch (without changing slice thickness)
    A. 1 only
    B. 2 only
    C. 1, 2 and 3
    D. 3 only
    D. 3 only
    (this multiple choice question has been scrambled)
  37. 15. Which of the following strategies minimizes beam hardening artifact from dense contrast media?
    1. the contrast solution can be diluted
    2. the scan can be performed with a slight delay
    3. the scan can be performed in the opposite direction
    A. 3 only
    B. 2 only
    C. 1, 2 and 3
    D. 1 only
    C. 1, 2 and 3
    (this multiple choice question has been scrambled)
  38. 34. Tube arcing might cause _____ on the images.
    A. shading and inaccurate CT numbers
    B. an appear of a cirlce or ring
    C. an increased appearance of noise
    D. star-like artifacts at the edges
    C. an increased appearance of noise
    (this multiple choice question has been scrambled)
  39. 5. Which of the following will have the least likelihood of producing edge gradient artifacts?
    A. thin slices iwth partial scan
    B. thin slices with full scan
    C. thick slice with full scan
    D. thick slices with partial scan
    B. thin slices with full scan
    (this multiple choice question has been scrambled)
  40. 17. Which of the following strategies will minimize metal artifacts?
    1. remove as much metal from the patient as possible
    2. orient slices such that the metal is avoided if possible
    3. inspect the localizer for any metal on the patient and remove any metal or avoid imaging it as much as possible
    A. 1 only
    B. 3 only
    C. 2 only
    D. 1, 2 and 3
    D. 1, 2 and 3
    (this multiple choice question has been scrambled)
  41. Which of the following will help reduce edge gradient effect?
    1. move structure causing artifact
    2. reposition patient
    3. increase data sampling
    4. use thinner slices
    A. 3 and 4 only
    B. 1 only
    C. 1 and 2 only
    D. 1, 2, 3, and 4
    D. 1, 2, 3, and 4
    (this multiple choice question has been scrambled)
  42. 3. A(n) ____ artifact can be created when attempting to correct for a cupping artifact by applying a correction algorithm too agressively to the data for a head image. This results in the ___ of the image appearing too bright.
    A. edge gradient, edges
    B. capping, center
    C. capping, edges
    D. edge gradient, center
    B. capping, center
    (this multiple choice question has been scrambled)

What would you like to do?

Home > Flashcards > Print Preview