MIC Ch2 CT Image Formation

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sully79
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308453
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MIC Ch2 CT Image Formation
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2015-09-24 12:53:52
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CT Registry Review MIC
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CT Image Formation
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  1. 7. Using _____ reconstruction filter would decrease the apparence of noise in a CT image.
    1. no
    2. a sharp
    3. a smooth
    A. 1 only
    B. 2 and 3
    C. 3 only
    D. 2 only
    C. 3 only
    (this multiple choice question has been scrambled)
  2. 18. A _____ scan uses only a single projection.
    1. conventional, or serial
    2. hilical
    3. localizer
    A. 1 only
    B. 2 only
    C. 3 only
    D. 1, 2 and 3
    C. 3 only
    (this multiple choice question has been scrambled)
  3. 15. Which of the following statements is FALSE regarding 3D SSD?
    A. patient motion during the scan is detrimental to the quality of the 3D images
    B. the tissue surface may be selected by using a threshold value equal to the tissue's CT number
    C. helical image data is well suited for 3D SSD because there is minimal misregistration or gaps
    D. the volume data, from which the 3D SSD is generated, is created by combining transverse, sagittal, and coronal reconstructions
    D. The volume data, from which the 3D SSD is generated, is created by combining transverse, sagittal, and coronal reconstructions
    (this multiple choice question has been scrambled)
  4. 27. Which type(s) of storage media may hold CT image data?
    1. internal hard disk
    2. CD
    3. re-writable optical disk
    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)
  5. 28. ____ may have to be edited fom the data set to get a diagnostic MIP of a CTA exam.
    A. Air
    B. Iodinated contrast media
    C. Vessells of interest
    D. Bones
    D. Bones
    (this multiple choice question has been scrambled)
  6. 23. Which of the following is NOT an advantage of a helical study compaired to a conventional, serial CT study?
    A. shorter total exam time
    B. offers the best image quality for a brain exam
    C. minimal anatomical misregistration sometimes caused by inconsistent breath-holding
    D. can retrospectively reconstruct a slice at any arbitrary position
    B. Offers the best image quality for a brain exam
    (this multiple choice question has been scrambled)
  7. 25. Which of the following utilizes convolution?
    1. 3D SSD
    2. Fourier transform
    3. filtered back projection
    A. 3 only
    B. 1 only
    C. 2 only
    D. 1,2 and 3
    A. 3 only
    (this multiple choice question has been scrambled)
  8. 29. In which technique are tissues other than the surface of a structure excluded by setting a threshold value and eliminating pixels above or below that threshold?
    A. 3D shaded surface display
    B. maximum intensity projection
    C. volume rendering
    D. multi-planar reconstruction
    A. 3D shaded surface display
    (this multiple choice question has been scrambled)
  9. 10. From which of the following can the most diagnostic multi-planar reconstructions be generated?
    1. stacked transverse images from a helical scan
    2. stacked transverse images from a conventional, serial scan
    3. stacked localizer images
    A. 2 only
    B. 1 only
    C. 1, 2 and 3
    D. 3 only
    B. 1 only
    (this multiple choice question has been scrambled)
  10. 6. The actual attenuation data measured by the detectors from all projections during a scan is contained in CT _____ data.
    1. image
    2. convolved
    3. raw
    A. 1 only
    B. 3 only
    C. 2 only
    D. 1,2 and 3
    B. 3 only
    (this multiple choice question has been scrambled)
  11. 39. Which of the following is TRUE regarding the slice thickness of an image reconstructed from a helical scan?
    1. on a multi-row scanner, the thickness is equal to the beam collimation
    2. on a single-row scanner, the thickness is wqual to the beam collimation
    3. on a single-row scanner, the thickness can be varied retrospectively
    A. 1,2 and 3
    B. 2 only
    C. 1 only
    D. 3 only
    B. 2 only
    (this multiple choice question has been scrambled)
  12. 4. A retrospective reconstruction, in which the reconstruction field-of-view is varied, uses:
    A. CT raw data
    B. a reconstructed image in the sagittal plane
    C. more photons
    D. CT image data
    A. CT raw data
    (this multiple choice question has been scrambled)
  13. Which of the following is common to both a localizer scan and a conventional, serial CT scan?
    A. they both produce digital images
    B. they both produce cross-sectional images
    C. the patient table moves at a constant velocity
    D. the x-ray tube make complete 360* rotations
    A. They both produce digital images
    (this multiple choice question has been scrambled)
  14. 30. Which of the following statements is TRUE?
    1. the amplified electrical signal obtained from the detectors must be digitized
    2. digital CT images are numerical representations of cross-sectional anatomy
    3. digital signals may be formed by sampling analog signals at discrete time intervals
    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. 1. ____ is the mathematical process used by single-row detector scanners to reconstruct CT images from raw data.
    A. Integration of the area under the curve
    B. Filtered back projection
    C. The Fourier transform
    D. Weighted averaging
    B. Filtered back projection
    (this multiple choice question has been scrambled)
  16. 38. 3D shaded surface displays are performed on CT:
    1. image data
    2. raw data
    3. attenuation profiles
    A. 1, 2 and 3
    B. 2 only
    C. 3 only
    D. 1 only
    D. 1 only
    (this multiple choice question has been scrambled)
  17. 11. A pixel is a:
    A. singe 2D picture element within the image plane
    B. range of gray levels on a CT image
    C. bright artifact on a film
    D. single 3D volume element within a volume of anatomical data
    A. Single 2D picture element within the image plane
    (this multiple choice question has been scrambled)
  18. 37. The pencil thin section of the x-ray fan beam that strikes a single detector is called a:
    A. view
    B. ray
    C. projection
    D. line
    B. Ray
    (this multiple choice question has been scrambled)
  19. 8. A kernel is a:
    A. post-processing filter applied to image data
    B. filter applied to the CT raw data
    C. component in the x-ray tube
    D. type of detector
    B. Filter applied to the CT raw data
    (this multiple choice question has been scrambled)
  20. 24. An increase in _____ does NOT occur in the resulting images when applying a sharp, or high-pass reconstruction filter during the image reconstruction of CT raw data
    1. contract resolution
    2. edge enhancement
    3. the appearance of noise
    A. 3 only
    B. 1 only
    C. 1, 2 and 3
    D. 2 only
    B. 1 only
    (this multiple choice question has been scrambled)
  21. 5. CTA images come from a _____ scan
    1. conventional, or serial
    2. helical
    3. localizer
    A. 3 only
    B. 2 only
    C. 1, 2 and 3
    D. 1 only
    B. 2 only
    (this multiple choice question has been scrambled)
  22. 13. If an image matrix has 360 rows and 360 columns, how manyu pixels are there in the image?
    A. 21,600
    B. 379,800
    C. 259,200
    D. 129,600
    D. 129,000

    a pixel is a 2-dimensional picture element defined by the rows and columns of the image matrix. f there are 360 rows and 360 columns in an image matrix, the total number of pixels in the image matrix is 360 x 360.
    (this multiple choice question has been scrambled)
  23. 36. The _____ determines the intensity of the laser beam in a aser camera.
    1. intensifying grid
    2. pixel values in the image data
    3. magnifying power of the lens
    A. 1, 2 and 3
    B. 3 only
    C. 1 only
    D. 2 only
    D. 2 only
    (this multiple choice question has been scrambled)
  24. 21. Which of the following is a reconstuction technique applied to the raw data after the primary reconstruction has already been accomplished?
    A. retrospective reconstruction
    B. volume rendering
    C. maximum intensity projection
    D. multi-planar reconstruction
    A. Retrospective reconstruction
    (this multiple choice question has been scrambled)
  25. 19. What does convolution do to the image quality when it si added to the back projection reconstruction process?
    A. increases the nubmer of projections thereby reducing streaking artifacts
    B. enhances important characteristics of attenuation profiles thus reducing streak and star artifacts
    C. normalizes the attenuation coefficients to ensure tissues are displayed with correct CT numbers
    D. improves contrast resolution by reducing scatter radiation
    B. Enhances important characteristics of attenuation profiles thus reducing streak and star artifacts
    (this multiple choice question has been scrambled)
  26. 34. Which of the following may occur during the interscan delay of a conventional, or serial, CT scan performed on a continuous ratation scanner?
    1. the table position is incremented
    2. the tube continues to rotate in the same direction as during the scan
    3. the tube assembly makes a 360* rotation
    A. 1, 2 and 3
    B. 2 only
    C. 3 only
    D. 1 only
    A. 1, 2, and 3
    (this multiple choice question has been scrambled)
  27. 32. _____ allows helical data to be converted into planar raw data.
    A. Retrospective reconstruction
    B. Interpolation
    C. Cone beam reconstruction
    D. Convolution
    B. Interpolation
    (this multiple choice question has been scrambled)
  28. What is the most common type of film used for recording CT images?
    A. double emulsion
    B. paper
    C. thermal
    D. single emulsion
    D. Single emulsion
    (this multiple choice question has been scrambled)
  29. 16. A helical scan performed on a 64 slice MDCT scanner is reconstruction with:
    A. simple reconstruction because it is a single projection scan
    B. no reconstruction filter
    C. back projection
    D. cone beam reconstruction
    D. Cone beam reconstruction
    (this multiple choice question has been scrambled)
  30. 26. _____ yields an image that appears 3D but also shoes anatomical details above and below the 3D surface.
    A. SSD
    B. VR
    C. MIP
    D. Multi-planar reconstruction
    B. VR
    (this multiple choice question has been scrambled)
  31. 2. MDCT scanners capable of collecting 64 slices in a single rotation do NOT:
    A. perform helical CT scans
    B. use filered back projection as their method of image reconstruction
    C. perform localizer scans
    D. perform conventional CT scans
    B. Use filtered back projection as their method of image reconstruction
    (this multiple choice question has been scrambled)
  32. 40. MIP images:
    A. are most accurate when a large volume of interest is selected
    B. do NOT demonstrate detail beneath the brightest pixel
    C. can NOT be run in a cine loop
    D. are most frequently used for visualixing air-filled spaces
    B. do NOT demonstrate detail beneath the brightest pixel
    (this multiple choice question has been scrambled)
  33. 31. Multi-planar reconstructions are performed on which of the following?
    1. image data
    2. raw data
    3. attenuation profiles
    A. 2 only
    B. 1, 2 and 3
    C. 1 only
    D. 3 only
    C. 1 only
    (this multiple choice question has been scrambled)
  34. 20. The _____ move(s) during a helical scan on a third-generation scanner,.
    1. x-ray tube
    2. patient table
    3. detector elements
    A. 1, 2 and 3
    B. 2 only
    C. 1 only
    D. 3 only
    A. 1, 2, and 3
    (this multiple choice question has been scrambled)
  35. 17. A CT system manufacturer has a scanner in which the focal spot of the x-ray beam can move to two, slightly separated, distinct locations. What benefit does the dual focal spot provide compared to an identical scanner possessing a single focal spot?
    1. the number of projections is doubled
    2. the nubmer of rays in a single projection is doubled
    3. the patient dose is halved
    A. 3 only
    B. 1 only
    C. 2 only
    D. 1, 2 and 3
    B. 1 only
    (this multiple choice question has been scrambled)
  36. 35. On a third-generation single-row detector scanner, if there are 715 detectors and there are 900 projections in a full rotation how many samples of attenuation data are collected for the raw data of a single slice if the scan calls for an overscan of a 400* rotation?
    A. 286,000
    B. 648,500
    C. 845,000
    D. 715,000
    D. 715,000

    There are 900 projections in a full rotation of 360*, but the question asks about an overscan of 400*. An overscan is sometimes used to decrease aliasing artifacts. 900 projections in 360* means that there are 900 / 360, or 2.5 projections per degree. There are 400-360, or 40 more degrees than a full scan. Multiplying 40 degrees by 2.5 projections per degree yields an additional 100 projections. Therefore, the total number of projections equals 900 + 100, or 1000 projecitons. The number of samples of attenuation profiles in the raw data equals thenumber of detectors time the number of projections 715 detectors x 1000 projections samples

    (this multiple choice question has been scrambled)
  37. 22. A smooth, or low-pass, reconstruction filter is typically NOT selected for a(n) _____ exam.
    A. liver
    B. kidneys
    C. internal auditory canals
    D. pituitary
    C. Internal auditory canals
    (this multiple choice question has been scrambled)
  38. 12. In a _____, the highest pixel values from a stack of CTA images are projected along many "rays"
    A. PR
    B. VR
    C. MIP
    D. SSD
    C. MIP
    (this multiple choice question has been scrambled)
  39. 3. The x-ray beam used in CT scanning is _____ the patient's tissues.
    1. reflected off of
    2. attenuated by
    3. generated by
    A. 3 only
    B. 1 only
    C. 1,2 and 3
    D. 2 only
    D. 2 only
    (this multiple choice question has been scrambled)
  40. How many samples of information comprising the raw data are there for a third generation, 64 row detector scanner with 850 detectors and 1700 projections acquired during a 360 degree rotation?
    a. 1,445,000
    b. 108,800
    c. 92,480,000
    d. unable to determine with these number
    • c. 92,480,000
    • 850 x 1700 x 64 = 92,480,000
  41. Reconstruction filter, or Kernel, is a filter that is applied to the raw date during image reconstruction. What is the process of applying this filter called?
    A. convolution
    B. filtered back projection
    C. interpolation
    D. multiplanar reconstruction
    A. convolution
    (this multiple choice question has been scrambled)
  42. What are the two basic types of reconstruction filters?
    Smooth and Sharp
  43. Which post-processing techniques use the image date?
    1. multi-planar reconstruction
    2. retrospective reconstruction
    3. 3D shaded surface display
    a. 1 only
    b. 2 only
    c. 1 and 2 only
    d. 1 and 3 only
    • d. 1 and 3 only
    • retrospective reconstruction uses raw image data
  44. The most accurate MIP results are obtained when a _____ volume of interest is selected.
    a. large
    b. small
    b. small
  45. Cone beam reconstruction is used when there are more than ____ slices in a single rotation being acquired.
    a. 1
    b. 4
    c. 16
    d. 64
    • b. 4
    • Filtered Back Projection is used when less than 4
  46. 9. Iterative reconstruction is:
    A. a second reconstruction process performed after the initial reconstruction in which a set of modified parameters is used
    B. a complex cycle of correction calculations applied during image reconstruction in order to reduce noise in the image
    C. typically performed on helical image data, to generate images in orientations other than those that can easily be directly acquired with CT
    D. the type of image reconstruction method used in CT before multi-row detector scanners became available
    B. a complex cycle of correction calculations applied during image reconstruction in order to reduce noise in the image
    (this multiple choice question has been scrambled)
  47. 14. Important clinical benefits of iterative reconstruction include:
    1. ability to reduce radiation dose without compromising image quality
    2. no longer needing to perform multi-planar reconstructions
    3. reduction in noise seen in the image
    A. 1, 2, & 3
    B. 2 & 3
    C. 1 only
    D. 1 & 3
    D. 1 & 3
    (this multiple choice question has been scrambled)

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