Question 1

Algorithms for sliding thin slabs include all of the following except:

Accepted Answer

The algorithms for sliding thin slabs (or thickening of multiplanar reconstruction images) include average intensity projection, maximum intensity projection, and minimum intensity projection.

Question 2

Limitations of maximum intensity projections include: 
I. artifacts from pulsating vessels
II. inability to show superimposed structures
III. images are three-dimensionally ambiguous unless depth cues are provided

Accepted Answer

Limitations of maximum intensity projection images include artifacts, the inability to show superimposed structures, and the images are three-dimensionally ambiguous unless depth cues are provided.

Question 3

Three-dimensional rendering algorithms include: 
I. virtual rendering
II. surface rendering
III. volume rendering

Accepted Answer

Two types of three-dimensional rendering algorithms are used in radiology: surface rendering and volume rendering.

Question 4

The processing of an object-based model into a simulated three-dimensional image involves: 
I. object delineation
II. rendering
III. segmentation

Accepted Answer

The processing of an object-based model into a simulated three-dimensional image involves all of the above: object delineation, rendering, and segmentation.

Question 5

Stages of volume rendering include: 
I. modeling
II. preprocessing
III. rendering

Accepted Answer

The two stages to volume rendering are preprocessing the volume and rendering.

Question 6

All of the following are tissue types used for voxel classification except:

Accepted Answer

Three tissue types-fat, soft tissue, and bone-are used for voxel classification.

Question 7

Which of the following is an algorithm intended to create a thick multiplanar reconstruction by using the average of the attenuation through the tissues of interest?

Accepted Answer

The average intensity projection technique is an algorithm that is intended to create a thick multiplanar reconstruction image by using the average of the attenuation through the tissues of interest to calculate the pixel viewed on the computer.

Question 8

Describe the role of the radiological technologist in three-dimensional computed tomography imaging.

Accepted Answer

The answer of Describe the role of the radiological technologist...

Question 9

Which algorithm provides a valuable perspective in defining lesions for surgical planning or detecting subtle small airway diseases?

Accepted Answer

Minimum intensity projection images may be useful in providing a valuable perspective in defining lesions for surgical planning or detecting subtle small airway diseases.

Question 10

All of the following are major elements of a typical three-dimensional imaging system except:

Accepted Answer

A typical three-dimensional imaging system consists of four major elements: input, workstation, output, and the user. The detector array is not a major element of the three-dimensional imaging system.

Question 11

Which of the following can be used to evaluate hollow structures such as the colon and the bronchi and can create an approach that allows for a "fly through"?

Accepted Answer

Perspective volume rendering is used to examine hollow structures such as the colon (computed tomographic colonoscopy) and the bronchi (computed tomographic bronchoscopy) and can create an approach that allows the operator to "fly through" the hollow structure.

Question 12

Clinical applications of three-dimensional imaging in computed tomography include all of the following except:

Accepted Answer

To date, clinical applications of three-dimensional imaging in computed tomography have been in the craniomaxillofacial complex, musculoskeletal system, central nervous system, cardiovascular system, pulmonary system, gastrointestinal system, and genitourinary system, as well as in radiation treatment planning for therapy.

Question 13

Which of the following algorithms uses only the tissues with the greatest attenuation?

Accepted Answer

In maximum intensity projections, the algorithm is such that only the tissues with the greatest attenuation will be displayed for viewing by an observer.

Question 14

All of the following are volume imaging methods except:

Accepted Answer

Volume imaging methods include holography, stereoscopic displays, anaglyphic methods, varifocal mirrors, synthalyzers, and rotating multidiode arrays. Polygonal methods are not involved in volume imaging.

Question 15

Which of the following uses voxel information to transform the images into a collection of objects with subsequent processing concentrating on the display of the objects?

Accepted Answer

Object-based processing uses voxel information to transform the images into a collection of objects with subsequent processing concentrating on the display of the objects.

Question 16

Anatomy missed as a result of patient respiration can have what type of appearance on the final three-dimensional image?

Accepted Answer

One of the fundamental problems of slice-by-slice computed tomographic scanning is that certain portions of the anatomy may be missed because motion caused by the patient's respiration can interfere with scanning or be inconsistent from scan to scan. This problem can lead to the appearance of steplike contours known as the stairstep artifact.

Question 17

Which type of three-dimensional imaging approach produces a true three-dimensional visualization?

Accepted Answer

Volume imaging produces a true three-dimensional visualization mode.

Question 18

Typical three-dimensional processing techniques include software to perform all of the following except:

Accepted Answer

Computer-aided diagnosis is not software for three-dimensional processing.

Question 19

Equipment for three-dimensional image processing includes: 
I. computed tomography or magnetic resonance imaging scanner console
II. memory and archiving computer
III. stand-alone computer workstations

Accepted Answer

Equipment for three-dimensional image processing falls into two categories: the computed tomography or magnetic resonance imaging scanner console and stand-alone computer workstations.

Question 20

An internal representation of surfaces that will be visible in the displayed image and then "lights" according to a standard protocol describes:

Accepted Answer

In surface rendering, the computer creates an internal representation of surfaces that will be visible in the displayed image. It then "lights" them according to a standard protocol and displays an image according to its calculation of how the light rays would be reflected to the viewer's eye.

Quiz 14: Three-Dimensional Computed Tomography: Basic Concepts