MICC PRACTICE TEST CH.2

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 transform.
D. Integration of the area under the curve.

Answer 1

B - Filtered back projection.

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.

Answer 2

C - use filtered back projections as their method of image reconstruction.

Question 3

The X-ray beam used in CT scanning is __________ the patients tissues.
1. reflected off of.
2. Attenuated by.
3. Generated by.

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

Answer 3

B - 2 only.

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.

Answer 4

B - CT raw 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, and 3.

Answer 5

B - Helical.

Question 6

The actual attenuation data measured by the detectors from all projections during a scan is contained in CT _________ data.
A. Image.
B. Convolved.
C. Raw.
D. All of the above.

Answer 6

C - Raw.

Question 7

Using __________ reconstruction filter would decrease the appearance of noise in a CT image.
A. No.
B. a sharp.
C. A smooth.
D. A sharp & smooth.

Answer 7

C - A smooth.

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.

Answer 8

D - filter applied to the CT raw data.

Question 9

Iterative reconstruction is:

A. A 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.

Answer 9

B - a complex cycle of correction calculations applied during image reconstruction in order to reduce noise in the image.

Question 10

From which of the following can the most diagnostic Multiplanar reconstruction be generated?
A. Stacked transverse images from a helical scan.
B. Stacked transverse images from a conventional, serial scan.
C. Stacked localizer images.
D. All of the above.

Answer 10

A - Stacked transverse images from a helical scan.

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.

Answer 11

C - Single 2D picture element within the image plane.

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.

Answer 12

B - MIP.

Question 13

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

Answer 13

129,600

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, and 3.

Answer 14

C - 1 & 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.

Answer 15

B.

Question 16

A helical scan performed on a 64 slice MDCT scanner is reconstructed with:
A. Back projection.
B. Simple reconstruction b/c it is a single projection scan.
C. No reconstruction filter.
D. Cone beam reconstruction.

Answer 16

D - Cone beam reconstruction.

Question 17

What is a convolution?

Answer 17

When a reconstruction filter is applied to the raw data during image reconstruction.

Question 18

A filter applied to the raw data during image reconstruction is called a:

Answer 18

Reconstruction filter or Kernel.

Question 19

Sharp Reconstruction Filter

Answer 19

Improves the definition of the edges of structures but does NOT minimize the grainy or speckled appearance in the image.

Question 20

Smooth Reconstruction Filter

Answer 20

Minimizes the grainy appearance of “noise” in the image so that the contrast between tissues can be better distinguished.
- it does NOT improve upon the edge definition.

Question 21

Sharp Filters

Answer 21

used when examining predominantly high contrast regions, such as musculoskeletal studies.

Question 22

Smooth Filters

Answer 22

Used when examining low contrast regions, such as the brain or abdomen.

Question 23

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?
A. The number of projection is doubled.
B. The number of rays in a single projection is doubled.
C. The pt dose is halved.
D. All of the above.

Answer 23

A - the number of projection is doubled.

Question 24

A __________ scan uses only a single projection.
A. Conventional, or serial.
B. Helical.
C. Localizer.
D. All of the above.

Answer 24

C - Localizer.

Question 25

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

Answer 25

It enhances important characteristics of attenuation profiles thus reducing streak & star artifacts.

Question 26

The __________ move(s) during a helical scan on a third-generation scanner. A. X-ray tube. B. Pt table. C. Detector elements. D. All of the above.

Answer 26

D - All of the above.

Question 27

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.

Answer 27

C - Retrospective reconstruction. (Accomplished AFTER the reconstruction of CT images!!).

Question 28

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.

Answer 28

D - Internal auditory canals. Low-pass helps visualize contrast between structures like the pituitary, kidneys, or liver. The auditory canals do not need contrast but need high spatial resolution from a sharper filter.

Question 29

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 beast image quality for a brain exam.

Answer 29

D- Offers the beast image quality for a brain exam. Advantages include: shorter exam times, minimal gaps between slices, minimal misregistration if completed in a single breathe hold.

Question 30

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. A. Contrast resolution. B. Edge enhancement. C. The appearance of noise. D. All of the above.

Answer 30

A. Contrast resolution. When a sharp, or high-pass reconstruction filter is convolved with the raw data, it greatly enhances the edges of the attenuation profiles. It does this at the expensive of contrast resolution, which is decreased.

Question 31

Which of the following utilizes convolution? A. 3D SSD. B. Fourier transform. C. Filtered Back Projection. D. All of the above.

Answer 31

C. Filtered back projection.

Question 32

__________ yields an image that appears 3D but also shows anatomical details above & below the 3D surface.

Answer 32

VR (Volume rendering).

Question 33

Which type(s) of storage media may hold CT image data? (Pick one or more answers). 1. Internal hard disk. 2. DVD. 3. Re-writable optical disk.

Answer 33

1, 2, and 3.

Question 34

__________ may have to be edited from the data set to get a diagnostic MIP of a CTA exam.

Answer 34

Bones.

Question 35

In which technique are tissues other than the surface of a structure excluded by setting a threshold value and eliminating pixels above/below that threshold?

Answer 35

3D shaded surface display.

Question 36

Which of the following statements is TRUE (click 1 or more) 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.

Answer 36

1, 2, and 3.

Question 37

Multi-planar reconstructions are performed on which of the following? (click 1 or more) 1. image data. 2. raw data. 3. attenuation profile.

Answer 37

1 only.

Question 38

__________ allows helical data to be converted into planar raw data.

Answer 38

Interpolation.