Question 1

Windowing in computed tomography is an example of:

Accepted Answer

Gray-level mapping is also popularly referred to as contrast enhancement, contrast stretching, histogram modification, histogram stretching, or windowing.

Question 2

When the window length is centered on the lungs, the image display is optimized for the lungs.

Accepted Answer

As graphically illustrated in Figure 8-12, when the window length is centered on the lungs (lower computed tomography numbers), the image display is optimized for that structure, and the liver (soft tissue) and pelvis (bone) are displayed as white.

Question 3

One major disadvantage of multiplanar reconstruction is that images are not as good as those obtained in transaxial images.

Accepted Answer

One major disadvantage of multiplanar reconstruction relates to image quality. Image detail is not as good as that obtained in transaxial images.

Question 4

Image smoothing is an example of a linear image manipulation technique.

Accepted Answer

Linear techniques include such processes as image smoothing and image enhancement.

Question 5

The window width in computed tomography is the:

Accepted Answer

The range in computed tomography in the image is referred to as the window width.

Question 6

Which of the following fall into the category of a linear image manipulation technique(s)? 
I. image enhancement
II. contrast stretching
III. image smoothing

Accepted Answer

Linear techniques include such processes as image smoothing and image enhancement.

Question 7

Which of the following determines the maximum number of gray shades to be displayed on the television monitor?

Accepted Answer

Window width determines the maximum number of shades of gray that can be displayed on the computed tomography monitor.

Question 8

A large window width means a long gray scale.

Accepted Answer

A large window width indicates that there is a relatively long gray scale.

Question 9

Windowing does not make use of the computed tomography numbers.

Accepted Answer

Windowing refers to a method by which the computed tomography image gray scale can be manipulated by using the computed tomography numbers of the image.

Question 10

Windowing is an example of a linear image manipulation technique.

Accepted Answer

Windowing is an example of gray-scale mapping.

Question 11

As the window width decreases, the image contrast increases.

Accepted Answer

As the window width decreases, the contrast becomes greater.

Question 12

Windowing is the most common image processing technique in computed tomography.

Accepted Answer

Windowing is the most common image processing technique used in computed tomography.

Question 13

Reconstruction synthesis operations create images from other images or nonimage data.

Accepted Answer

Image synthesis operations create images from other images or nonimage data.

Question 14

A narrow window width implies that the transition from black to white will take place over a wide range of computed tomography numbers.

Accepted Answer

A narrow window width implies that the transition from black to white will take place over relatively few computed tomography numbers.

Question 15

Through the manipulation of computed tomography numbers of the various tissues, the picture can be changed to show soft tissues and dense structures such as bone.

Accepted Answer

Through the manipulation of computed tomography numbers of the various tissues, the picture can be changed to show soft tissues and dense structures such as bone.

Question 16

The range of computed tomography numbers is the window length.

Accepted Answer

The range of CT numbers is the WW.

Question 17

Gray-level mapping belongs to the class of:

Accepted Answer

One common algorithm of interest used in computed tomography routinely by technologists and radiologists alike is based on a point processing technique, also referred to as gray-level mapping.

Question 18

Multiplanar reconstruction creates three-dimensional images from the transaxial data set.

Accepted Answer

Multiplanar reconstruction is a computer program that can create coronal, sagittal, and paraxial images from a stack of contiguous transverse axial scans.

Question 19

The computed tomography number for water is +1000.

Accepted Answer

The midpoint of the range (window length) is 0; this is referred to as a reference point because it represents water.

Question 20

A narrow window width means fewer computed tomography numbers.

Accepted Answer

A narrow window width implies that the transition from black to white will take place over relatively few computed tomography numbers.

Quiz 8: Image Postprocessing and Visualization Tools

Windowing in computed tomography is an example of:

When the window length is centered on the lungs, the image display is optimized for the lungs.

One major disadvantage of multiplanar reconstruction is that images are not as good as those obtained in transaxial images.

Image smoothing is an example of a linear image manipulation technique.

The window width in computed tomography is the:

Which of the following fall into the category of a linear image manipulation technique(s) ? I. image enhancement II. contrast stretching III. image smoothing

Which of the following determines the maximum number of gray shades to be displayed on the television monitor?

A large window width means a long gray scale.

Windowing does not make use of the computed tomography numbers.

Windowing is an example of a linear image manipulation technique.

As the window width decreases, the image contrast increases.

Windowing is the most common image processing technique in computed tomography.

Reconstruction synthesis operations create images from other images or nonimage data.

A narrow window width implies that the transition from black to white will take place over a wide range of computed tomography numbers.

Through the manipulation of computed tomography numbers of the various tissues, the picture can be changed to show soft tissues and dense structures such as bone.

The range of computed tomography numbers is the window length.

Gray-level mapping belongs to the class of:

Multiplanar reconstruction creates three-dimensional images from the transaxial data set.

The computed tomography number for water is +1000.

A narrow window width means fewer computed tomography numbers.