Deck 5: Image Reconstruction

Question 1

Image data are obtained:

A) after convolution.
B) after preprocessing.
C) after back-projection.
D) before back-projection.

Answer 1

after back-projection.

Question 2

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.

Answer 2

convolution.

Question 3

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

Answer 3

Fourier transform

Question 4

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

Question 5

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

A) perpendicular
B) parallel
C) long
D) short

Question 6

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

Question 7

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

Question 8

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.

Question 9

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

Question 10

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

A) Algorithm
B) Fourier transform
C) Interpolation
D) Convolution

Question 11

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

Question 12

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

Question 13

A set of ray sums is referred to as a:

A) ray sum.
B) projection.
C) total ray projection.
D) view.

Question 14

FBP is also referred to as the ______________ _______________.

A) convolution method
B) interpolation method
C) algorithm method
D) iterative method

Question 15

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

Question 16

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

Question 17

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

Question 18

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

Question 19

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

Question 20

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

A) Hounsfield
B) convolution
C) Fourier
D) Ambrose

Question 21

The new generation of MSCT scanners requires modified image reconstruction algorithms.

Question 22

The signals that leave the CT detectors are subject to preprocessing.

Question 23

Please match the image reconstruction concepts. All answer selections will be used just once.

Fourier transform

A)Set of directions for getting a specific output from a specific input
B)Mathematical technique of value estimation
C)Converts signals in the spatial domain to the frequency domain
D)Digital image processing technique to modify images through filter function
E)Generation of multiple attenuated measurements

Question 24

The algorithms for the single-slice (SCCT) and MSCT scanners with four detector rows are referred to as spiral/helical fan-beam approximation algorithms.

Question 25

Please match the image reconstruction concepts. All answer selections will be used just once.

Interpolation

A)Set of directions for getting a specific output from a specific input
B)Mathematical technique of value estimation
C)Converts signals in the spatial domain to the frequency domain
D)Digital image processing technique to modify images through filter function
E)Generation of multiple attenuated measurements

Question 26

The results of preprocessing are referred to as image data.

Question 27

Convolution kernels can be applied to any type of data.

Question 28

Please match the image reconstruction concepts. All answer selections will be used just once.

Projection

A)Set of directions for getting a specific output from a specific input
B)Mathematical technique of value estimation
C)Converts signals in the spatial domain to the frequency domain
D)Digital image processing technique to modify images through filter function
E)Generation of multiple attenuated measurements

Question 29

Please match the image reconstruction concepts. All answer selections will be used just once.

Convolution

A)Set of directions for getting a specific output from a specific input
B)Mathematical technique of value estimation
C)Converts signals in the spatial domain to the frequency domain
D)Digital image processing technique to modify images through filter function
E)Generation of multiple attenuated measurements

Question 30

Please match the image reconstruction concepts. All answer selections will be used just once.

Algorithm

A)Set of directions for getting a specific output from a specific input
B)Mathematical technique of value estimation
C)Converts signals in the spatial domain to the frequency domain
D)Digital image processing technique to modify images through filter function
E)Generation of multiple attenuated measurements

Question 31

A large cone beam will result in cone-beam artifacts.

Question 32

The Fourier transform is a technique for estimating a function from known values on both sides of it.

Question 33

An algorithm is a set of rules for solving a problem.

Question 34

The algorithms for three-dimensional imaging are based on those used in computer graphics and visual perception science.

Question 35

The measurement of the total X-ray absorption of a particular ray is defined as a view.