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Computed Tomography Questions and
Correct Answers/ Latest Update /
Already Graded
What is windowing?
Ans: A method in which the CT image gray scale can be manipulated in
order to enhance different structures of varying tissues
What are the 2 windowing mechanisms?
Ans: - Window width
- Window level
What is Window Width (WW)?
Ans: - The range of the CT numbers in the image
- Determines the maximum number of shades of gray that can be
displayed on the CT monitor
- Effects contrast
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What is Window Level (WL)?
Ans: - The center or midpoint of the range of CT numbers
- Effects brightness
Wide window widths (400 to 2000 HU) are necessary for ____?
Ans: Varying body tissues
Narrow window widths (50 to 350 HU) are necessary for ____?
Ans: Different tissues of similar densities
What are the effects of WW on image contrast?
Ans: - As the WW increases, the contrast decreases
- As the WW decreases, the contrast increases
What are the effects of WL on image brightness?
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Ans: - Moving the WL toward the higher CT numbers results in a darker
image
- Moving the WL toward the lower CT numbers results in a brighter image
What is a multi-slice scanner (MSCT)?
Ans: - CT system equipped with a multiple-row detector array to
simultaneously collect data at different slice locations
- Can scan up to 64 slices
In CT, the attenuated image-forming radiation is detected by what?
Ans: A solid state image receptor
What is Helical CT?
Ans: - Continuous gantry rotation + continuous table feed
- Scan data traces a helical path or spiral around patient
What is Isotropic Imaging?
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Ans: 2D pixel in a CT image represents a 3D voxel
Name the 3 types of Data acquisition systems?
Ans: - Conventional
- Helical single slice (spiral)
- Multi-slice
What is a Linear Attenuation coefficient?
Ans: Characterizes how easily a volume of material can be penetrated
by the x-rays
What is a bowtie filter?
Ans: Used to allow a uniform beam to reach detectors
What occurs with CT filtration?
Computed Tomography Questions and
Correct Answers/ Latest Update /
Already Graded
What is windowing?
Ans: A method in which the CT image gray scale can be manipulated in
order to enhance different structures of varying tissues
What are the 2 windowing mechanisms?
Ans: - Window width
- Window level
What is Window Width (WW)?
Ans: - The range of the CT numbers in the image
- Determines the maximum number of shades of gray that can be
displayed on the CT monitor
- Effects contrast
,2 | Page
What is Window Level (WL)?
Ans: - The center or midpoint of the range of CT numbers
- Effects brightness
Wide window widths (400 to 2000 HU) are necessary for ____?
Ans: Varying body tissues
Narrow window widths (50 to 350 HU) are necessary for ____?
Ans: Different tissues of similar densities
What are the effects of WW on image contrast?
Ans: - As the WW increases, the contrast decreases
- As the WW decreases, the contrast increases
What are the effects of WL on image brightness?
,3 | Page
Ans: - Moving the WL toward the higher CT numbers results in a darker
image
- Moving the WL toward the lower CT numbers results in a brighter image
What is a multi-slice scanner (MSCT)?
Ans: - CT system equipped with a multiple-row detector array to
simultaneously collect data at different slice locations
- Can scan up to 64 slices
In CT, the attenuated image-forming radiation is detected by what?
Ans: A solid state image receptor
What is Helical CT?
Ans: - Continuous gantry rotation + continuous table feed
- Scan data traces a helical path or spiral around patient
What is Isotropic Imaging?
, 4 | Page
Ans: 2D pixel in a CT image represents a 3D voxel
Name the 3 types of Data acquisition systems?
Ans: - Conventional
- Helical single slice (spiral)
- Multi-slice
What is a Linear Attenuation coefficient?
Ans: Characterizes how easily a volume of material can be penetrated
by the x-rays
What is a bowtie filter?
Ans: Used to allow a uniform beam to reach detectors
What occurs with CT filtration?
