Quiz

Question 1

____________ is the mathematical process used by single-row detector scanners to reconstruct CT images from raw data.

A. Weighted averaging
B. Filtered back projection
C. The Fourier form
D. Integration of the area under the curve

Question 2

MDCT scanners capable of collecting 64 slices in a single rotation do NOT:

A. Perform conventional CT scans
B. Perform helical CT scans
C. Use filtered back projection as their method of image reconstruction
D. Perform localizer scans

Question 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. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3

Question 4

A retrospective reconstruction, in which the reconstruction field-of-view is varied, uses:

A. A reconstructed image in the sagittal plane
B. CT raw data
C. More photons
D. CT image data

Question 5

CTA images come from a ______________ scan.
1. Conventional, or serial
2. Helical
3. Localizer

A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3

Question 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. 2 only
C. 3 only
D. 1, 2, & 3

Question 7

Using ____________ reconstruction filter would decrease the appearance of noise in a CT image.
1. No
2. A sharp
3. A smooth

A. 1 only
B. 2 only
C. 2 & 3
D. 3 only

Question 8

A kernel is a:

A. Component in the x-ray tube
B. Post-processing filter applied to image data
C. Type of detector
D. Filter applied to the CT raw data

Question 9

Iterative reconstruction is:

A. 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
C. A second reconstruction process performed after the initial reconstruction in which a set of modified parameters is used
D. Typically performed on helical image data, to generate images in orientations other than those that can easily be directly acquired with CT

Question 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. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3

Question 11

A pixel is a:

A. Bright artifact on a film
B. Single 3D volume element within a volume of anatomical data
C. Single 2D picture element within the image plane
D. Range of gray levels on a CT image

Question 12

In a ____________, the highest pixel values from a stack of CTA images are projected along many “rays”.

A. SSD
B. MIP
C. PR
D. VR

Question 13

If an image matrix has 360 rows and 360 columns, how many pixels are there in the image?

A. 21,600
B. 129,600
C. 259,200
D. 379,800

Question 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 only
B. 2 & 3
C. 1 & 3
D. 1, 2, & 3

Question 15

Which of the following statements is FALSE regarding 3D SSD?

A. Helical image data is well suited for 3D SSD because there is minimal misregistration or gaps
B. The volume data, from which the 3D SSD is generated, is created by combining transverse, sagittal, and coronal reconstructions
C. The tissue surface may be selected by using a threshold value equal to the tissue’s CT number
D. Patient motion during the scan is detrimental to the quality of the 3D images

Question 16

A helical scan performed on a 64 slice MDCT scanner is reconstructed with:

A. back projection
B. Simple reconstruction because it is a single projection scan
C. No reconstruction filter
D. Cone beam reconstruction

Question 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 processing a single focal spot?
1. The number of projections is doubled
2. The number of rays in a single projection is doubled
3. The patient dose is halved

A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3

Question 18

A _____________ scan uses only a single projection.
1. Conventional, or serial
2. Helical
3. Localizer

A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3

Question 19

What does convolution do to the image quality when it is added to the back projection reconstruction process?

A. Normalizes the attenuation coefficients to ensure tissues are displayed with correct CT numbers
B. Increases the number of projections thereby reducing streaking artifacts
C. Improves contrast resolution by reducing scatter radiation
D. Enhances important characteristics of attenuation profiles thus reducing streak and star artifacts

Question 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 only
B. 2 only
C. 3 only
D. 1, 2, & 3

Question 21

Which of the following is a reconstruction technique applied to the raw data after the primary reconstruction has already been accomplished?

A. Maximum intensity projection
B. Volume rendering
C. Retrospective reconstruction
D. Multi-planar reconstruction

Question 22

A smooth, or low-pass, reconstruction filter is typically NOT selected for a(n) ___________ exam.

A. pituitary
B. Kidneys
C. Liver
D. Internal auditory canals

Question 23

Which of the following is NOT an advantage of a helical study compared to a conventional, serial CT study?

A. Minimal anatomical misregistration sometimes caused by inconsistent breath-holding
B. Shorter total exam time
C. Can retrospectively reconstruct a slice at any arbitrary position
D. Offers the best image quality for a brain exam

Question 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. Contrast resolution
2. Edge enhancement
3. The appearance of noise

A. 1 only
B. 2 only
C. 3 only
D. 1, 2, & 3

Question 25

Which of the following utilizes convolution? 1. 3D SSD 2. Fourier transform 3. Filtered back projection A. 1 only B. 2 only C. 3 only D. 1, 2, & 3

Question 26

_____________ yields an image that appears 3D but also shows anatomical details above and below the 3D surface. A. SSD B. VR C. MIP D. Multi-planar reconstruction

Question 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, & 3

Question 28

_____________ may have to be edited from the data set to get a diagnostic MIP of a CTA exam. A. Iodinated contrast media B. Vessels of interest C. Air D. Bones

Question 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. Volume rendering B. Multi-planar reconstruction C. Maximum intensity projection D. 3D shaded surface display

Question 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 only B. 2 only C. 3 only D. 1, 2, & 3

Question 31

Multi-planar reconstructions are performed on which of the following? 1. Image data 2. Raw data 3. Attenuation profiles A. 1 only B. 2 only C. 3 only D. 1, 2, & 3

Question 32

_____________ allows helical data to be converted into planar raw data. A. Retrospective reconstruction B. Interpolation C. Cone beam reconstruction D. Convolution

Question 33

DIAGRAM QUESTION - SKIP

Answer 33

SKIPPED

Question 34

Which of the following may occur during the interscan delay of a conventional, or serial, CT scan performed on a continuous rotation 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 only B. 2 only C. 3 only D. 1, 2, & 3

Question 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. 643,500 C. 715,000 D. 845,000

Question 36

The ____________ determines the intensity of the laser beam in a laser camera. 1. Intensifying grid 2. Pixel values in the image data 3. Magnifying power of the lens A. 1 only B. 2 only C. 3 only D. 1, 2, & 3

Question 37

The pencil thin section of the x-ray fan beam that strikes a single detector is called a: A. Line B. Projection C. View D. Ray

Question 38

3D shaded surface displays are performed on CT: 1. Image data 2. Raw data 3. Attenuation profiles A. 1 only B. 2 only C. 3 only D. 1, 2, & 3

Question 39

Which of the following is TRUE regarding the slice thickness of an image reconstructed from a helical scan? 1. On a multi-row detector scanner, the thickness is equal to the beam collimation 2. On a single-row detector scanner, the thickness is equal to the beam collimation 3. On a single-row detector scanner, the thickness can be varied retrospectively A. 1 only B. 2 only C. 2 & 3 D. 1, 2, & 3

Question 40

MIP images: A. Are most frequently used for visualizing air-filled spaces B. Can NOT be run in a cine loop C. Are most accurate when a large volume of interest is selected D. Do NOT demonstrate detail beneath the brightest pixel