Chapter 05: Image Reconstruction

Which of the following refers to a function that relates to the amplitude and phases of a sine wave and corresponds to a specific frequency?

a.

Fourier transform

b.

Algorithm

c.

Convolution

d.

Interpolation

Fourier transform

Which is a mathematical technique used to estimate the value of a function from known values on either side of the function?

a.

Convolution

b.

Interpolation

c.

Back-projection

d.

Projection ratio

Interpolation

Which of the following is a digital image processing technique used to modify images through a filter function?

a.

Convolution

b.

Interpolation

c.

Back-projection

d.

Projection filter

Convolution

A set of ray sums is referred to as a:

a.

ray sum.

b.

projection.

c.

total ray projection.

d.

view.

projection.

Hounsfield's first scanner used _________________ beam projections acquired through a 180-degree rotation.

a.

perpendicular

b.

parallel

c.

long

d.

short

parallel

All of the following describe basic problems with the back-projection algorithm except:

a.

the produced image is blurred.

b.

the image not useful for clinical CT.

c.

compares assumptions with measured values.

d.

the image suffers from a star pattern artifact.

compares assumptions with measured values.

Which algorithm belongs to the class of analytical algorithms for CT?

a.

Back-projection

b.

Filtered back-projection (FBP)

c.

Iterative reconstruction (IR)

d.

Fourier reconstruction

Filtered back-projection (FBP)

Which of the following reconstruction algorithms was used by Hounsfield in his original experiments?

a.

Back-projection

b.

Algebraic reconstruction technique

c.

Fourier transform

d.

FBP

Algebraic reconstruction technique

Which of the following algorithms is most commonly used in the state-of-the-art CT scanners?

a.

Iterative algorithms

b.

Back-projection

c.

FBP

d.

Fourier reconstruction

FBP

The result of the preprocessing of the signals from the CT detectors is called:

a.

convolved data.

b.

raw data.

c.

image data.

d.

back-projected data

raw data.

The first operation to which raw data is subjected is referred to as:

a.

convolution.

b.

back-projection.

c.

three-dimensional surface shading.

d.

interpolation.

convolution.

Image data are obtained:

a.

after convolution.

b.

after preprocessing.

c.

after back-projection.

d.

before back-projection.

after back-projection.

Which of the following describes the beam that diverges from the X-ray tube to the outer edges of the detectors?

a.

Cone beam

b.

Aperture beam

c.

Straight beam

d.

Fan beam

Cone beam

Which is a class of cone-beam algorithms available for use with the new generation of multislice CT (MSCT) scanners?

a.

Filtered cone-beam algorithms

b.

Convoluted cone-beam algorithms

c.

Exact cone-beam algorithms

d.

Three-dimensional cone-beam algorithms

Exact cone-beam algorithms

Which of the following refers to a defined set of instructions for solving a problem?

a.

Algorithm

b.

Fourier transform

c.

Interpolation

d.

Convolution

Algorithm

Which of the following will allow the user to interactively visualize, manipulate, and measure large three-dimensional objects on general-purpose workstations?

a.

Three-dimensional algorithms

b.

Interpolation algorithms

c.

Fourier transform

d.

Three-dimensional convolution

Three-dimensional algorithms

The use of __________ coefficients makes it possible to reconstruct an image in CT.

a.

Hounsfield

b.

Convolution

c.

Fourier

d.

Ambrose

Fourier

Which of the following algorithms compares an assumption with the measured values, makes corrections, and then repeats the process?

a.

Analytical reconstruction algorithms

b.

Back-projection

c.

IR algorithms

d.

Fourier reconstruction algorithms

IR algorithms

FBP is also referred to as the ______________ _______________.

a.

convolution method

b.

interpolation method

c.

algorithm method

d.

iterative method

convolution method

Which of the following removes the classical star pattern artifact of the back-projection algorithm?

a.

Interpolation

b.

Fourier reconstruction

c.

FBP

d.

Iterative algorithm

FBP