Question 1

In surface rendering, surface formation is the first step, and it involves the operation of contouring.

Accepted Answer

Surface rendering involves essentially two steps: surface formation and depiction on a computer screen. Surface formation involves the operation of contouring.

Question 2

The most familiar coordinate system is the:

Accepted Answer

The most familiar system is the xyz, the scene or cartesian coordinate system, as it is commonly called.

Question 3

The purpose of three-dimensional imaging is to use large amounts of data collected from the patient to provide both qualitative and quantitative information.

Accepted Answer

The purpose of three-dimensional imaging is to use the vast amounts of data collected from the patient by volume computed tomography scanning (and other imaging modalities such as magnetic resonance imaging, for example) to provide both qualitative and quantitative information in a wide range of clinical applications.

Question 4

Computer-aided diagnosis helps the observer view three-dimensional space by displaying the front, back, top, and bottom of an object.

Accepted Answer

Computer software helps the observer to view three-dimensional space by displaying the front, back, top, and bottom of the object, providing a perspective from the observer's vantage point, a technique known as computer-aided visualization or three-dimensional visualization.

Question 5

Ray tracing involves a mathematical ray sent from the observer's eye through the two-dimensional computer screen to pass through the three-dimensional volume that contains opaque and transparent objects.

Accepted Answer

During ray tracing, a mathematical ray is sent from the observer's eye through the two-dimensional computer screen to pass through the three-dimensional volume that contains opaque and transparent objects.

Question 6

In the scene (xyz) coordinate system, the axes are positioned at __________ angles.

Accepted Answer

In this system, the x, y, and z-axes are positioned at right angles (orthogonal) to one another.

Question 7

The x, y, and z coordinates define a space in which multidimensional data are represented, which is called the: 
I. three-dimensional space
II. cartesian space
III. scene space

Accepted Answer

The x, y, and z coordinates define a space in which multidimensional data (a set of slices) are represented, which is called the three-dimensional space or scene space.

Question 8

Only some of the information collected from the voxels that compose each of the scanned slices goes to the computer for image reconstruction.

Accepted Answer

All information collected from the voxels that compose each of the scanned slices goes to the computer for image reconstruction.

Question 9

__________ information is used to assess the three elements of technique of the three-dimensional imaging procedure.

Accepted Answer

Quantitative information is used to assess three elements of the technique: precision (reliability), accuracy (true detection), and efficiency (feasibility) of the three-dimensional imaging procedure.

Question 10

Which modeling technique transforms a two-dimensional profile into a three-dimensional object?

Accepted Answer

In extrusion, one of the most common techniques, computer software is used to transform a two-dimensional profile into a three-dimensional object.

Question 11

Three-dimensional imaging has found applications in all of the following except:

Accepted Answer

In radiology, three-dimensional imaging has found applications in radiation therapy, craniofacial imaging for surgical planning, orthopedics, neurosurgery, cardiovascular surgery, angiography, and magnetic resonance imaging. Another use of three-dimensional imaging has been in the visualization of ancient Egyptian mummies without destroying the plaster or bandages.

Question 12

The generation of a three-dimensional object by using computer software is called:

Accepted Answer

The generation of a three-dimensional object with computer software is called modeling.

Question 13

Virtual endoscopy allows the viewer to "fly through" structures such as: 
I. colon
II. tracheobronchial tree
III. vessels

Accepted Answer

Three-dimensional imaging has created virtual endoscopy, a technique that allows the viewer to "fly through" the body in an effort to examine structures such as the brain, tracheobronchial tree, vessels, sinuses, and the colon.

Question 14

The zero point is also called the:

Accepted Answer

Use of the coordinate system allows description of an object by measuring distances from the point of intersection, or zero point.

Question 15

Volume rendering produces three-dimensional images that have a better image quality and provide more information compared with surface rendering.

Accepted Answer

Volume rendering is a more sophisticated technique and produces three-dimensional images that have a better image quality and provide more information compared with surface-rendering techniques.

Question 16

The creation of the simulated three-dimensional image from data collected from the object space is called:

Accepted Answer

Rendering is the final step in the process of generating a three-dimensional object. It involves the creation of the simulated three-dimensional image from data collected from the object space.

Question 17

Voxel-based processing makes determinations about each voxel and decides to what degree each should contribute to the final three-dimensional image.

Accepted Answer

Voxel-based processing makes determinations about each voxel and decides to what degree each should contribute to the final three-dimensional display.

Question 18

Slice imaging is the most complex of all three-dimensional imaging.

Accepted Answer

Slice imaging is the simplest method of three-dimensional imaging.

Question 19

The development of computed tomographic angiography and three-dimensional imaging has not proved effective in the evaluation of cerebral aneurysms and arteriovenous malformations.

Accepted Answer

The development of computed tomographic angiography opened up additional avenues for the use of three-dimensional imaging in the evaluation of cerebral aneurysms and arteriovenous malformations.

Question 20

All of the following are shading algorithms except:

Accepted Answer

There are several shading algorithms, including wireframe shading, flat shading, Gouraud shading, and Phong shading. Polygonal shading is not a shading algorithm.

Quiz 14: Three-Dimensional Computed Tomography: Basic Concepts