Chapter 08: Image Postprocessing and Visualization Tools

Gray-level mapping belongs to the class of:

a.

point processing technique.

b.

local processing technique.

c.

global processing technique.

d.

geometrical processing technique.

a.

point processing technique.

Windowing in CT is an example of:

a.

a local processing operation.

b.

convolution.

c.

gray-level mapping.

d.

an image reconstruction algorithm.

c.

gray-level mapping.

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

a.

Window level (WL)

b.

Window width (WW)

c.

Contrast controls on the television monitor

d.

Filtered back-projection (FBP) algorithm

b.

Window width (WW)

The WW in CT is the:

a.

center of a range of CT numbers.

b.

pixel depth.

c.

range of CT numbers.

d.

dimension of the matrix.

c.

range of CT numbers.

The WL in CT is the:

a.

center of a range of CT numbers.

b.

pixel depth.

c.

range of CT numbers.

d.

center of the CT matrix.

a.

center of a range of CT numbers.

If the WW setting is 200 and the WL is 0, which of the following occurs?

a.

CT numbers greater than +100 appear white

b.

CT numbers less than 100 appear gray

c.

CT numbers between 0 and +200 appear black

d.

Only those numbers between +100 and +200 appear gray

a.

CT numbers greater than +100 appear white

An examination of the abdomen has a WW of 400 and a WL of 0. Which of the following is true given these settings?

a.

All structures between -200 and 200 will spread through the gray scale

b.

All structures between -200 and 200 will be white

c.

All structures between -200 and 200 will be black

d.

Only those structures above 400 will have different shades of gray

a.

All structures between -200 and 200 will spread through the gray scale

Which of the following controls the contrast of the CT image?

a.

Peak kilovoltage (kVp)

b.

Milliamperage

c.

WL

d.

WW

d.

WW

Which of the following optimizes the image display for a particular structure?

a.

kVp

b.

Milliamperage

c.

WW

d.

WL

d.

WL

What happens to a CT image when the WL moves toward the lower CT numbers?

a.

Appears darker

b.

Appears white

c.

Longer gray scale

d.

Shorter gray scale

b.

Appears white

A large WW indicates that there is a relatively ______________ gray scale.

a.

long

b.

short

c.

narrow

d.

curved

a.

long

Which of the following generates sagittal, coronal, and paraxial images from transaxial slices?

a.

Back-projection reconstruction

b.

FBP reconstruction

c.

Multiplanar reconstruction

d.

Radiation treatment planning CT

c.

Multiplanar reconstruction

Which of the following is a plot of the pixel values as a function of their frequency of occurrence?

a.

Region of interest (ROI) statistics

b.

CT histogram

c.

Highlighting

d.

Multiple windowing

b.

CT histogram

Which of the following basic visualization tools allows for the mean and standard deviation within a given ROI?

a.

ROI statistics

b.

CT histogram

c.

Highlighting

d.

Multiple windowing

a.

ROI statistics

Which of the following are not categories of three-dimensional rendering?

a.

Surface-shaded display

b.

Volume rendering

c.

Maximum and minimum intensity projections

d.

Windowing

d.

Windowing

Which advanced tool in CT allows users to view a large set of images very quickly?

a.

Cine visualization

b.

Advanced quantitative measurement

c.

Interactive visualization

d.

Virtual reality visualization

a.

Cine visualization

In which of the following are pixels in a certain region of the image made to appear brighter?

a.

Highlighting

b.

Image magnification

c.

ROI transfer

d.

Point-to-point imaging

a.

Highlighting

Which of the following belongs to the class of nonlinear image manipulation techniques?

a.

Image enhancement

b.

Image smoothing

c.

Gray-scale manipulation

d.

Linear smoothing

c.

Gray-scale manipulation

As the WW increases, picture contrast:

a.

increases.

b.

decreases.

c.

remains unchanged.

d.

is optimized to show the specific anatomical structures.

b.

decreases.

One industry standard in data transfer and connectivity is:

a.

Digital Imaging and Communications in Medicine (DICOM).

b.

hospital information system.

c.

radiology information system.

d.

picture archiving and communications system.

a.

Digital Imaging and Communications in Medicine (DICOM).