CT Comprehensive Final Exam

What is the purpose of the host computer in a digital image processing system?

The host computer performs several functions that ranges reading and writing in the image storage and provides for archival storage on tape and disk storage systems. The host computer also plays a significant role in applications that involve the transmission of images to another location.

The output digital image must first be converted into an analog signal. True or False

True

The sine wave is an example of an analog signal. True or False

True

Which of the following are dual-source computed tomography scanners primarily used for imaging?

cardiac imaging

The detectors convert the attenuation data into ____________ signals.

electrical

Which of the following is not an imaging application of the computer? Film library functions magnetic resonance imaging computed tomography digital radiography

film library functions

The use of graphic symbols to indicate the sequence of operations needed to solve a problem is called a:

flow chart

The radiation used by Hounsfield in his original experiments was

gamma rays

A computer system consists of:

hardware, software, and people (3)

Which of the following refers to modifying computed tomographic data to make the images more useful to the observer?

image manipulation

Star networks can be applied to which of the following?

local area network

When a beam of x rays passes through the patient, the relative transmission or penetration measurement can be calculated by use of which of the following? 1. ratio of the source intensity to the detector intensity 2. ratio of the detector intensity to the source intensity 3. log of the ratio of the detector intensity to the source intensity 4. log of the ratio of intensity of x-rays at the source to the intensity of the dector

log of the ratio of intensity of x rays at the source to the intensity of the detector

The contraction for "picture element" is: 1. matrix 2. pixel 3. address 4. voxel

pixel

Which of the following best describes the term "data acquisition geometry" in computed tomography? 1. the size and shape of the xray beam 2. the stationary ring of detectors 3. the arrangement of the xray tube and detectors 4. the rotation of the x-ray tube

the arrangement of the x-ray tube and detectors

The center or mid point of the range of computed tomography numbers is called the: 1. window level 2. contrast factor 3. region of interest 4. window width

window level

If the linear attenuation coefficients for bone and water are 0.380 and 0.190, respectively, and the scaling factor of the scanner is 1000, the computed tomography number for bone is: 1. +380 2. +1000 3.+190 4. 1000

+1000

The computed tomography number for water is: 1. -100 2. 0 3. 100 4. -1000

0

Which analog-to-digital converter (ADC) is more accurate with respect to sampling an analog signal? 1. 2- bit ADC 2. 16-bit ADC 3. 8-bit ADC 4. 4-bit ADC

16-bit ADC

Which of the following is a limitation of computed tomography compared with conventional radiography? 1. A decreased spatial resolution 2. increased contrast resolution 3. decreased patient dose 4. decreased visualization of artifacts

A decreased spatial resolution

Explain briefly what is meant by convolution.

A technique of filtering in the spatial domain rather than in the frequency domain

Which acronym has been established by the Radiological Society of North America for use in major American radiology journals?

CT

Which of the following is best used to describe patient dose in computed tomography?

CTDI and MSAD

A group of 16 bits equals 1 byte.

False

Computed tomography is not well established in the study of diseases of the central nervous system.

False

Determining tissue types in computed tomography slices is referred to as volume formation.

False

Digitization consists of four steps: scanning, sampling, quantization, and digital-to-analog conversion True or False

False

The arithmetic-logic unit is part of the control unit. True or False

False

The keyboard is an example of output hardware.

False

What contribution did Cormack make to the development of clinical computed tomography?

He developed the solutions to the mathematical problems in computed tomography.

Who developed the first clinically useful computed tomography scanner?

Hounsfield

The photoelectric effect occurs more frequently in tissues with a: I. high atomic number II. low atomic number III. high Z number IV. low Z number

I and III

Which type(s) of image compression results in no loss of information in the compressed image data? I. lossless II. lossy III. reversible IV. irreversible

I and III

A digital image: 1.cannot be processed by a digital computer 2. is a numerical representation of an object 3. is a nonvisible physical image 4. is a continuous image

Is a numerical representation of an object

The following are examples of applications software Framework Microsoft works Ms-Dos First Choice

MS-DOS

Which of the following chips provide temporary storage of data and programs to be processed by the central processing unit? PROM chips ROM chips EEPROM chips RAM chips

RAM chips

The origin of digital image processing stems from: 1. General Electric 2. the Mayo Clinic 3. Hounsfield 4. the space program

Space program

A bit is a contraction for binary digit. true or false

True

A limitation of conventional radiography is that it is qualitative rather than quantitative. True or False

True

A technique of filtering in the spatial domain rather than in the frequency domain is convolution. True or False

True

Aliasing results in an artifact that appears as a moiré pattern in the image. True or False

True

An analog-to-digital converter consists of a sampler, a quantizer, and a coder.

True

Computed tomography has been applied to the study of internal log defects and Egyptian mummies.

True

Computers are now used in radiology to process images. True or false

True

Conversion of the attenuation readings into a computed tomography image is accomplished by reconstruction algorithms. True or false

True

Digital image processing can be defined as "subjecting numerical representations of objects to a series of operations to obtain a desired result." True or False

True

Digital image processing techniques have been applied successfully in not only the space program but also in medical imaging. True or False

True

In 1996, the U.S. Food and Drug Administration approved real-time computed tomography fluoroscopy as a clinical tool for use in radiology

True

Isodose curves are a dose descriptor used in reporting radiation doses in computed tomography.

True

PACS is an acronym for picture archiving and communications systems.

True

Quality control is well established in computed tomography.

True

The British Department of Health and Social Security assisted in the development of the first clinically useful computed tomography scanner

True

The British Department of Health and Social Security assisted in the development of the first clinically useful computed tomography scanner.

True

The Compton effect occurs largely in soft tissues. True or False

True

The Fourier transform is used to transform one image domain into another image domain.True or False

True

The window width controls the image contrast and the window level controls the image brightness. True or False

True

Three-dimensional algorithms, or rendering techniques, transform the transaxial computed tomography data into simulated three-dimensional images.

True

A histogram in digital image processing is: 1 a plot of the number of pixels as a function of the number of gray levels 2 a spatial frequency filter 3 a local operation 4 a windowing level

a plot of the number of pixels as a function of the number of gray levels

Which type of artifact will appear on a digital image as a result of poor sampling of the analog signal? 1. partial volume 2. beam hardening 3. aliasing 4. poor sampling does not create artifacts

aliasing

Which of the following is not true of a homogeneous beam of radiation? 1. equal thicknesses of the absorber remove equal amounts of radiation 2. all the photons have different energies 3. all the photons have the same energy 4. equal thicknesses of the absorber remove different amounts of radiation

all the photons have different energies

The reduction of the intensity of a beam of x rays as it passes through the patient is:

attenuation

The computer science application that deals essentially with the display of pictures on a computer screen is called:

computer graphics

Which of the following uses software as a tool to provide additional information to the radiologist to make a diagnosis?

computer-aided detection (CAD)

Which of the following directs the activities of the computer using instructions stored in memory? inernal memory arithmetic-logic unit control unit registers and buses

control unit

In which of the following are slices taken at specific locations on the patient? 1. spiral computed tomography 2. helical computed tomography 3. volumetric computed tomography 4. conventional slice-by-slice computed tomography

conventional slice-by-slice computed tomography

All these elements can be used during data acquisition to reduce patient dose except

decreased pitch

In which of the following are numerical representations of objects subjected to a series of operations to produce a desired result? 1. analog-to-digital conversion 2. pattern recognition 3. digital image processing 4. digital-to-analog conversion

digital image processing

Data from the computed tomography detectors are first sent to the _________ before going to the computer. 1. array processor 2. host computer 3. digitizers 4. back projector

digitizers

A computed tomography image of 12 bits per pixel means: 1. the voxel size is 12mm 2. each pixel can have a total of 4096 shades of gray 3. the pixel size is 12mm 4. the matrix is 4096 x 4096

each pixel can have a total of 4096 shades of gray

Which type of image processing technique is intended to modify the spatial position of the pixels in an image? 1. geometric processing operation 2. local processing operation 3. global processing operation 4. point processing operation

geometric processing operation

Data processing includes all of the following except: 1. raw data preprocessing 2. image storage 3. analog to digital conversion 4. image reconstruction

image storage

An increase of matrix size (with no change in field of view) will ____________ detail. 1. not change 2. have no effect on 3. increase 4. deacrease

increase

Computer processing involves, in order programming, output, and input input, output, and processing input, programming, and output input, processing, and output

input, processing, and output

Which image processing hardware is responsible for high-speed processing of the input digital data? 1. digitizer 2. internal image processor 3. host computer 4. image memory

internal image processor

The unit of the linear attenuation coefficient (m) is: 1. per cm-2 2. per centimeter 3. cm 1 4. 1/cm

per centimeter

Secondary storage refers to Optical disks read only-memory magnetic tapes magneic disks

read-only memory

An example of a local operation that concerns brightness information on an image is called: 1 histogram modication 2 spatial frequency filtering 3 convolution 4 area processes

spatial frequency filtering

In which of the following data acquisition methods is a volume of tissue (rather than a single slice) scanned during a single breath hold? 1. spiral/helical computed tomography 2. conventional radiograph computd tomography 3. slice-by-slice computed tomography 4. conventional computed tomography

spiral/helical computed tomography

The following developments in computed tomography were introduced during the period between 1973-1983 except 1. spiral/helical compued tomography 2. detectors 3. image quality improvements 4. quality control

spiral/helical computed tomography

The limitations of conventional tomography include all of the following except: 1. a superimposition of structures above and below the focal plane 2. the presence of ghost images on the film 3. image blur from movement of the tube and film 4. conrast degradation from the open beam geometry

the presence of ghost images on the film

The field of view is: 1. a mathematical technique 2. a digital processing technique 3. the region of interest 4. the reconstruction circle

the reconstruction circle

The purpose of image enhancement is: 1 to allow measurments and statistics to be performed 2 to reduce the size of the image 3 to improve the quality of images that have distortions 4 to generate an image more pleasing to the observer

to generate an image more pleasing to the observer

Which of the following became the first commercially available computer? abacus difference engine universal automatic computer electronic tabulator

universal automatic computer

A 10 x 10 matrix consists of ______ pixels. 1. 100 2. 20 3. 120 4. 10

100

An eight-bit microprocessor can represent 64 numbers 8 numbers 256 numbers 16 numbers

256 numbers

How many pixels make up a computed tomography image whose matrix size is 512 x 512?

262,144

The most obvious difference between computed tomography and radiography is that: 1. radiograph shows cross-sectional images 2. radiograpy uses sodium iodide detectors 3. A computed tomography shows cross sectional images or transaxial anatomy 4. A computer is used to produce the film in radiography

A computed tomography shows cross-sectional images or transaxial anatomy

Natural languages include acronyms such as BASIC, COBOL, and FORTRAN. True or False

False

Attenuation of a beam of radiation depends on: I. the atomic number II. the electrons per gram of tissue III. the energy if the radiation

I, II, and III

Who developed the first whole-body computed tomography scanner?

Ledley

The process of dividing a picture into small regions called pixels is referred to as: 1 sampling 2 analog-to-digital conversion 3 scanning 4 quantization

Scanning