Chapter 5: Digital Image Processing, Display, and Data Management

What is the communication standard for information sharing between PACS and imaging modalities?

DICOM

Decreasing the window level will result in an image with:

Decreased brightness

A value that reflects the difference between the desired or target exposure to the IR and the actual exposure to the IR is the:

Deviation index (DI)

A communication standard for information sharing between PACS and imaging modalities

Digital Imaging and Communications in Medicine (DICOM)

The DICOM recommended standard for consistent display characteristics, such as grayscale appearance and image quality.

grayscale standard display function (GSDF)

Display monitors used for soft-copy viewing of digital images should have _________________.

high luminance

Graphic display of the distribution of pixel values. Each image has is own, and it is evaluated to determine the adequacy of the IR exposure to x-rays.

histogram

The computer analyzes the histogram using processing algorithms and compares it with a pre-established (reference) histogram specific to the anatomic part being imaged.

histogram analysis

A facility's system to collect and store personal patient information gathered that will assist in his/her care.

hospital information system (HIS)

The location of the histogram along the x-axis represents:

image brightness levels

Involves data management for radiology services both within and outside the health care system.

imaging informatics

The y-axis of the histogram graph represents:

incidence (frequency) of pixel values

A postprocessing technique that reverses the grayscale from the original image

inversion

Image compression where there is no loss of image data (lossless) at the end user.

irreversible compression

Initiative by health care professionals and industry to improve the way computer systems in health care share information.

Integrating the Healthcare Enterprise (IHE)

What digital process alters image brightness and grayscale to improve the visibility of anatomic structures?

LUTs

The __________ provides a method of altering the brightness and grayscale of the digital image.

Look up table

Increasing the window width will result in an image with:

Lower contrast

_______________ is a measurement of the light intensity (brightness) emitted from the surface of the display monitor.

Luminance

A technique that can remove superimposed structures so that the anatomic area of interest becomes more visible. Because the image is in digital format, the computer can subtract selected brightness values to create and image without superimposed structures.

dual-energy subtraction

A postprocessing technique that improves the visibility of small, high-contrast structures

edge enhancement

The system for patient health information (PHI) that can be shared outside the facility and among many health care systems.

electronic health record (EHR)

Also known as shuttering, A postprocessing function that can remove regions of the digital image.

electronic masking

A postprocessing function whereby underexposed areas (light areas) are made darker and overexposed areas (dark areas) are made lighter. The effect is an image that appears to have lower contrast so that dense and lucent structures can be better seen within the same image.

equalization

A numeric value that is displayed on the processed image to indicate the level of x-ray exposure received on the digital image receptor.

exposure indicator

The number of different shades of gray that can be stored and displayed by a computer system.

grayscale

Determines the range of the histogram data set included in the displayed image

values of interest (VOIs)

allows for images and data from different systems and in different formats to be stored using a singular system on a common infrastructure

vendor neutral archives (VNAs)

sets the midpoint of the range (center) of brightness visible in the digital image

window level

The range or number of shades of gray visible on the digital image.

window width

The histogram is a graphic representation of the ___________.

Range and incidence of pixel values

This post processing technique improves the visibility of image noise.

Smoothing

What postprocessing technique suppresses image noise?

Smoothing

Overexposing a digital image receptor may result in a quality image, but:

The ALARA principle has not been followed

Health information that can be linked to an individual must be secured and protected. (T/F)

True

Maintaining a low level of ambient lighting can improve soft-copy viewing of digital images. (T/F)

True

Once the data is in digital format, there is no difference between image processing and display between CR and DR. (T/F)

True

The deviation index (DI) is a value that reflects the difference between the desired or target exposure to the IR and the actual exposure to the IR. (T/F)

True

Transmission devices need to have the capacity to handle the volume of images, delivered within a reasonable timeframe and, can check for errors. (T/F)

True

The range of the histogram data set that should be included in the displayed image is determined by the:

VOIs

The width to height dimensions of a display monitor

aspect ratio

Occurs during histogram analysis and is used to maintain consistent image brightness despite overexposure or underexposure of the digital image receptor.

automatic rescaling

Digital image processing refers to:

computer manipulations applied to digital data

A postprocessing technique that alters the pixel values to increase image contrast

contrast enhancement

The ability of the IR to distinguish between objects having similar subject contrast.

contrast resolution

A complex system-wide effort to ensure that people, equipment, and processes are in place to expand health care communication and improve patient outcomes.

data management

Wider window width _____________.

decreases contrast

A value that reflects the difference between the desired or target exposure to the image receptor and the actual exposure to the IR

deviation index (DI)

Various computer algorithms (mathematical computations) applied to digital data for the purpose of optimizing the image for display

digital image processing

A requirement to duplicate all files in a remote location so that recovery is possible in the event of a disaster and the primary files are lost.

disaster recovery

A desktop computer that allows for the retrieval and viewing of medical images from one of the modalities or storage components of the PACS.

display workstation

Which of the following may impact the location and shape of the histogram? 1. Exposure technique 2. Positioning 3. Collimation

1, 2, and 3

Which of the following may occur as a result of the DI value greater than +3.0? 1. Excessive noise visible 2. Saturation 3. Patient overexposure

2 and 3 only

Source of digital imaging artifacts include: A. All options are correct B. Scratches on the IP and calibration of DR detector elements C. Scratches on the IP and malfunction of IP transport mechanisms D. Malfunction of IP transport mechanism and calibration of DR detector elements

A. All options are correct

What process is employed to maintain consistent digital image brightness for over or underexposure? A. Automatic rescaling B. Histogram C. Exposure indicator D. Lookup tables (LUTs)

A. Automatic rescaling

In order to improve the quiality of the displayed image, LUTs:

Alter the pixel values of the exposure histogram to match the reference histogram

Because of the electronic components of a DR image receptor, imperfections can lead to _____________:

Artifacts and malfunctioning pixels

Soft copy viewing means that the image is being viewed:

At a computer

What process is employed to maintain consistent digital image brightness for over or underexposure?

Automatic rescaling

Factors that affect the location and shape of the histogram include: A. Positioning and anatomic area imaged B. All options are correct C. Collimation and positioning D. Commination and anatomic area imaged

B. All options are correct

The number of bits that determines the amount of precision in digitizing the analog signal and the number of gray shades that can be displayed in the image is the:

Bity depth

Which of the following deviation index (DI) values indicate excessive exposure: A. 2.5 B 2000 C. +3 D. 300

C. +3

Which of the following is defined as a graphic representation of the pixel values? A. Automatic rescaling B. Values of interest C. Histogram D. Exposure Indicator

C. Histogram

Which of the following is not a numerical value indicating the level of radiation exposure to a digital image receptor (IR)? A. Sensitivity number B. Exposure indicator C. Window level D. Exposure index

C. Window level

To transmit and store large amounts of imaging data, what may occur?

Compression

This post processing technique improves the visibility of small, high contrast structures.

Edge enhancement

The numerical value indicating the level of radiation exposure to the digital IR is the:

Exposure indicator

A DI of -0.75 reflects insufficient exposure to the IR. (T/F)

False

Standards established to protect the privacy and confidentiality of patient's information is known as:

Health Insurance Portability and Accountability Act

National standards for electronic health care transactions and national identifiers for providers, health insurance plans, and employers.

Health Insurance and Portability and Accountability Act (HIPAA)

What standard was enacted to protect privacy and confidentiality of patient's health information?

Health Insurance and Portabilityand Accountability Act

A communication standard for medical information

Health Level Seven standard (HL7)

The process that uses computer algorithms to compare with stored (reference) histograms is known as:

Histogram analysis

Which of the following is not a function during postprocessing of a displayed digital image? A. Histogram analysis B. Electronic masking C. Windowing D. Edge enhancement

Historgram analysis

What digital image processing stage prepares the raw data for processing and display?

Pre-processing

A mechanism for the radiographer to reprocess the image data by selectin and alternative anatomical region or projection to improve its presentation at the display monitor.

alternative algorithms

Provide a method of altering the image to change the display of the digital image in a variety of ways

lookup table (LUTs)

The emission of light from the screen when stimulated by radiation

luminance

The greater the pixel bit depth, the _________ the digitization of the analog signal, and the _________ the number of shades of gray available for image display.

more precise; greater

A computer system designed for digital imaging that can receive, store, distribute, and display digital images

picture archival and communication system (PACS)

Postprocessing function that provides calculation of selected pixel values within the area of interest to provide quantitative information about the tissue.

region of interest (ROI)

Image compression where there is no loss of image data (lossless) at the end user.

reversible compression

A postprocessing technique that suppresses image nosie (quantum noise). However, spatial resolution is degraded.

smoothing

A postprocessing operation to combine multiple images into one image for viewing anatomic areas such as for a scoliosis series.

stitching

The practice of diagnostic image interpretation outside the facility (offsite) from where the imaging data is acquired.

teleradiology