Imaging Worksheets for Chapters 31, 32, and 33

Even with the most sensitive digital imaging systems, true saturation requires at least _______ times the normal exposure to occur. A) B) C) D)

8

A loss of image data is reflected in the characteristic curve of the histogram showing ______________. A) B) C) D)

a shallower slope

High- pass filtering only allows _____________ to pass through processing to the final displayed image. A) B) C) D)

high frequencies

Which of the following is associated with the digital imaging edge-enhancement features? A) B) C) D)

high-pass filtering

On most digital systems, image brightness can be increased by ______________. A) B) C) D)

holding the mouse button down and moving the cursor to the right and/or downward

The weakest link in the radiographic imaging chain is usually the ____________. A) B) C) D)

image display system

What problem can over-use of edge-enhancement features cause in a digital image? A) B) C) D)

increased noise

In a digital image, low frequencies represent ____________. A) B) C) D)

large objects

For gradation (gradient) processing, the S values from the rescaled data set are fed into a(n) _______________. A) Anatomical LUT B) Permanent LUT C) Band-pass filter D) Kernel E) DAC

A) Anatomical LUT

For the gradation processing curves developed early on by Fuji, the shape of a particular curve which a particular algebraic formula generates is represented by the parameter __________. A) GT B) GS C) GA D) GC

A) GT

The CareStream CR system uses a logarithmic scale for its exposure indicator, with an ideal index number of 2000. If a radiograph is produced with an exposure index of 2300, what change in radiographic technique would bring it back to the ideal amount? A) Reduce to one half B) Double C) Reduce to one third D) Triple E) Reduce mAs by 300

A) Reduce to one-half

Which is the most appropriate term when describing the capabilities of a hardware device such as a display monitor? A) Bit depth B) Dynamic range C) Gray Scale D)Compression ratio

A) bit depth

In any digital image, the distance from the center of one pixel to the center of the next adjacent pixel is the _________. A) pixel pitch B) pixel span C) spatial frequency D) average detail sze

A) pixel pitch

Noise in the image caused y electronic malfunctions is normally periodic, occurring at regular intervals across the image, (rather than random, such as quantum mottle). This periodic type of noise is best eliminated from a digital image using __________. A) processing in the frequency domain B) processing in the spatial domain C) gradation processing D) histogram analysis

A) processing in the frequency domain

A more accurate term describing what dynamic range compression really does is gray scale ____________. A) truncation B) lengthening C) shortening D) Compression E) leveling

A) truncation

Tissue equalization or dynamic range compression can improve _______________. A) under penetrated portions of the image B) light areas of cortical bone in the image C) dark areas of lung tissue in the image D) computer memory storage space

A) under penetrated portions of the image

A histogram is the result when a digital image is sorted by the _____________. A) Values contained by each pixel B) Size of the structures within it C) Location of each pixel D) Location of each structure within it

A) values contained by each pixel

All of the following are general domains in which a digital image can be processed except: A) intensity B) amplitude C) frequency D) spatial

B) Amplitude

Sorting an image by the size of the structures within it results in a(n) ____________. A) LUT B) frequency distribution C) histogram D) matrix

B) frequency distribution

In digital image processing, high-pass and low-pass filtering are methods of ___________. A) histogram analysis B) frequency processing C) re-scaling D) partitioned pattern recognition

B) frequency processing

In any image, the very smallest details present can be collectively represented as _______________. A) short waves with low frequencies B) short waves with high frequencies C) long waves with low frequencies D) long waves with high frequencies

B) short waves with high frequencies

What would an example of an area operation? A) A windowing width adjustment B) Darkening the image overall C) Zoom (magnification) D) Unsharp mask filtering

C) Zoom (magnification)

Inverting an image top-for-bottom would be a(n) _________ operation. A) Point B) Area C) Global D) Kernel

C) Global

What default process is reapplied whenever a displayed image is windowed? A) Band-pass filtering B) Uniformity correction C) Gradation processing D) Detail processing E) Dynamic range compression

C) Gradation processing

The wave functions of details within an image most closely resemble ______________. A) gradation processing curves B) histograms C) density trace diagrams D) look up tables

C) density trace diagrams

From a selected mid-point in the various gray levels of a digital image, lighter areas in the image are progressively darkened, while darker areas are progressively lightened. What does this describe? A) multiscale processing B) normalization C) dynamic range compression D) rescaling of brightness E) flat-field uniformity correction

C) dynamic range compression

To demonstrate soft tissue structures on a digital image, which of the following windowing combinations is the best? A)High window width, high window level B)Low window width, high window level C)high window width, low window level D)low window width, low window level

C) high window width, low window level

One main reason that the dynamic range of a digital image processing system must be much greater than the actual gray scale used in the image is to prevent data clipping when the _________________. A) image is acquired B) histogram is constructed C) image is windowed for brightness or contrast D) image is rescaled for brightness or contrast E) image is compressed

C) image is windowed for brightness or contrast

A smaller "core" matrix of mathematical values which is passed though the entire image matrix multiplying the value of each pixel sequentially by the nubers in it, is called a(n) ____________. A) region of interest B) look up table C) kernel D) fourier transform E) interpolation chart

C) kernel

For the "black bone" processing feature, which inverts all brightness values within the image, the gradation curve is _______________. A) shifted to the left of the y axis of the graph B) shifted under the x axis of the graph C) reversed D) shifted to the right

C) reversed

Which manufacturer refers to its exposure indicator as the exposure index? A) B) C) D)

CareStream (Kodak)

Every image begins and ends in the __________ domain. A) Intensity B) Amplitude C) Frequency D) Spatial

D) Spatial

Point, area, and global operations are all subcategories within the _________ domain. A) Intensity B) Amplitude C) Frequency D) Spatial

D) Spatial

When routine radiographic techniques are used, which are dramatic benefits of dynamic range compression (DRC) or tissue equalization? 1) Computer memory space is saved 2) Lung tissue is better demonstrated 3) Soft tissues are better demonstarted A) 2 & 3 only B) 1 & 3 only C) 1 & 2 only D) 1 ,2, & 3

D) computer memory space is saved, lung tissue is better demonstrated, soft tissues are better demonstrated

A high window level will result in which of the following on the displayed digital image? A)High Contrast B) Long gray scale C) Bright Image D) Dark Image

D) dark image

If dynamic range of a digital processing system is too limited, it is possible for ________ to occur when the displayed image is later windowed. A) Quantum mottle B) Electronic Noise C) Image reversal D) Data Clipping E) Excessive Contrast

D) data clipping

Sorting an image by the location of its pixels results in a (n): A) LUT B) frequency distribution C) histogram D) matrix

D) matrix

The application of a single mathematical operation equally to each and every pixel in the images is a(n) ____________. A) frequency processing operation B) gradation processing operation C) normalization operation D) point processing operation

D) point processing operation

Which manufacturer uses the S-number to adjust brightness in the image? A) B) C) D)

Fuji

The standardized exposure indicator recommended by the AAPM in 2009 is based on actual exposure to the image detector measured in ________________. A) B) C) D)

Kerma

Display magnification of a digital image is controlled by all of the following except ___________. A) B) C) D)

SID/OID ratio

What concept is defined as the difference in signal contribution (intensity) between two specific tissue areas, divided by the background noise level? A) B) C) D)

Signal-to-noise ratio (SNR)

For GE's look feature, a "hard", "normal", or "soft" look can be applied to the image. The soft look actually applies a ____________ algorithm. A) B) C) D)

Smoothing

The end result of unsharp mask filtering is that ___________ are suppressed in the final image A) B) C) D)

gross structures

Which of the following methods preserves the original data set for an image while allowing modifications in its appearance on the display monitor to be made? A) B) C) D)

alternate algorithms

Which of the following may use a bar code from the CR cassette? A) B) C) D)

assigning an image to a study

True saturation is a phenomenon that occurs ________________. A) B) C) D)

at the electronic DR detector plate

For each image in the PACS, the exposure indicator is to be permanently stored as part of the DICOM _____________. A) B) C) D)

header

Default settings for smoothing and edge enhancement features _________________________. A) B) C) D)

can be excessive enough to cause misdiagnosis

For most CR systems, dragging the cursor vertically on the display screen can be used to adjust the displayed image _____________. A) B) C) D)

contrast

Agfa's MUSICA digital processing suite uses the finest detail (highest frequency) image layer to derive a(n) ___________ image, which is later used to distinguish between actual noise and similar details. A) B) C) D)

contrast to noise ratio (CNR)

The rescaling (processing) step is best considered as a subset of the preprocessing category because rescaling can be thought of as making ______________. A) B) C) D)

corrections for flaws in an image acquisition

Which of the following features would be generally recommended for all images being viewed. A) B) C) D)

dark masking

How is the "speed" of the CR system determined? A) B) C) D)

department management and QC technologist decide what will be upon installation

Which of the following is to be prominently displayed immediately after every exposure to indicate how far off the radiographic technique was from an ideal exposure level? A) B) C) D)

deviation index

The use of low-pass filtering (smoothing) will tend to ______________. A) B) C) D)

eliminates the appearance of high-attenuation artifacts from the image

For dual energy subtraction to produce bone only and soft tissue only images, it must first use either variable filters or variables kVp settings to obtain high and low - ___________ images. A) B) C) D)

energy

Which of the following is a possible ill effect of edge enhancement? A) B) C) D)

excessive noise

Anything that can result in a histogram error can result in _____________. A) B) C) D)

exposure indicator error

Mottle is likely to appear in the computerized image any time the ______________. A) B) C) D)

exposure indicator is very low

When edge enhancement is applied to an image that already possesses high contrast, an artifact may be caused in which the dark and light sides of edges are exaggerated. This artifact is called _____________. A) B) C) D)

halo effect

One of the main advantages of multi-scale digital processing is that a narrow band of _______________ can be separate and have its signal boosted to enhance visualization of specific size of structures. A) B) C) D)

frequencies

The normal acceptable range of exposure readings is 100 to 400 for which brand? A) B) C) D)

fuji

Carestream Health's perceptual tone scaling uses human psychophysical models in final preparation of the digital image for display, and is also unique in that it maps ______________ against these models to obtain final output pixel values. A) B) C) D)

input exposure value

Mottle in a CR or DR image can result from ______________. A) B) C) D)

insufficient mAs

An anatomical LUT is a table generated by applying a(n) __________ to the incoming data set. A) Intensity transformation formula B) Algebraic formula C) Algebraic function curve D) Any of these E) None of these

intensity transformation formula, algebraic formula, algebraic function curve

The speed of a digital imaging system is ___________ to the amount of exposure required to produce adequate signal for processing. A) B) C) D)

inversely proportional

During unsharp mask filtering, what problem can the use of too small a kernel cause? A) B) C) D)

loss of diagnostic detail

To subtract grid lines from an image produced with a stationary grid, grid lines suppression software defines and treats these lines as _________. A) B) C) D)

low-frequency structures with a single pixel

For unsharp mask filtering in the spatial domain, the larger the size of the kernel used for averaging pixel values, the ___________ the resulting mask image. A) B) C) D)

more blurry

True saturation presents an area of the image with ________________. A) B) C) D)

no details at all present

As part of post-processing, after detail processing and noise reduction are completed, the image has an alien look on it. In final preparation for display, in order to conform the image to human perception, it is subjected to an additional round of _____________. A) B) C) D)

normalization

The exposure indicator is _______________ related to the brightness of the image displayed on the monitor screen. A) B) C) D)

not

While a histogram graph plots the number of pixels against each pixel value, a frequency distribution plots the number of ___________ against their size. A) B) C) D)

objects

Fore all manufactures, the acceptable range of exposure indicator values is determined by the original x-ray exposure falling within what range of the "ideal" exposure level? A) B) C) D)

one-half to double

Dual-energy subtraction takes advantage of marked differences in __________ absorption between soft tissues and bone. A) B) C) D)

photoelectric

If an entire digital image was composed only of low frequencies, the image would have _____________. A)

poor sharpness

For a radiograph, image reversal ______________ and is _____________. A) B) C) D)

produces a black on white image present only subjective visual changes to the image

An inverse Fourier transform is used to __________. A) B) C) D)

re-assembles the different wavelengths in an image

When windowing the displayed image, extreme reduction of contrast may ___________ the image. A) B) C) D)

reverse

No overexposed digital image should ever be repeated, no matter the EI, unless ______________ has occurred. A) B) C) D)

saturation

When an alternate algorithm has been used to successfully improve an image, the best follow-up for PACS storage is to ___________________. A) B) C) D)

save both the original and the copy as separate files

When approving CR images, why should the radiographer generally not save adjustments made to the brightness and contrast of a "sub-optimal" original image into the PACS? A) B) C) D)

saving the changes into PACS permanently erases some image data

For a quality digital image, the highest possible _______________ should be achieved. A) B) C) D)

signal-to-noise ratio

Which of the following features suppresses image noise (mottle) with an attendant slight decrease in contrast throughout the image? A) B) C) D)

smoothing

Nearly all modern CR and DR systems can be operated at a ___________ of 350 or 400 without the appearance of substantial mottle in the image. A) B) C) D)

speed class

For all digital imaging systems, a lower limit for exposure to the receptor is imposed by ________________. A) B) C) D)

the appearance of quantum mottle

Which of the following is determined by the computer by finding the mid-point between Smin and Smax in the main lobe of the generated histogram image? A) B) C) D)

the exposure indicator

The mathematical method by which a complex wave form representing one line of digital image can be broken down into a set of different individual wavelengths that make it up is known as ___________. A) B) C) D)

the fourier transformation

During pyramidal decomposition of an image, the lowest-frequency image, the "bottom image in the stack" requires ____________. A) B) C) D)

the least amount of storage space

for systems using an inverted scale for their exposure index, a high original "S'' number indicates _____________. A) B) C) D)

too low original exposure