Chapter 3- Digital Radiographic Image Processing and Manipulation

Failure of the reader to find the collimation edges of an image:

A. will result in image cutoff.

B. may cause the image to be too bright or too dark.

C. will eliminate all scatter.

D. will have no effect on the resultant image.

B

If the entire range of exposure were digitized, pixel values representing ______ would be digitized.

A. scatter

B. only diagnostic values

C. only the extreme values

D. all values

D

Data collected within the collimator are represented by a:

A. histogram.

B. characteristic curve.

C. pixel graph.

D. matrix graph.

A

A histogram displays the useful signal by locating:

A. all pixel values.

B. maximum and minimum signal.

C. maximum signal only.

D. minimum signal only.

B

The higher the kilovoltage peak, the:

A. wider the histogram.

B. narrower the histogram.

C. higher the frequency.

D. lower the frequency.

B

The Nyquist theorem states that the:

A. sampling frequency must be equal to the input signal bandwidth.

B. input signal bandwidth must be twice the sampling frequency.

C. sampling frequency must be twice the input signal bandwidth.

D. input signal bandwidth must be sampled twice.

C

If too few pixels are sampled, the result will be:

A. high resolution.

B. low resolution.

C. high contrast.

D. low contrast.

B

Raw data used to form the image histogram are compared with:

A. a normal histogram referenced by the computer.

B. all histograms stored for that anatomic part.

C. the last histogram of that anatomic part.

D. none of these.

A

Loss of detail in a digitally processed image:

A. occurs because of the number of conversions.

B. is extremely minimal compared with film/screen.

C. is equal to film/screen.

D. has almost no impact on the image

A

The longer an image is stored in the computed radiography (CR) cassette, the:

A. more detailed the processed image.

B. more energy is lost by the electrons.

C easier the image is to process.

D. slower the processing time.

B

A wraparound image or image aliasing occurs when:

A. sampling occurs twice per cycle.

B. spatial frequency is less than the Nyquist frequency.

C. sampling occurs less than twice per cycle.

D. spatial frequency is equal to the Nyquist frequency.

C

In an effort to display the pixels for the area of interest when exposure is greater or less than what is needed to produce an image, ______ occurs.

A. overexposure

B. underexposure

C. automatic collimation

D. automatic rescaling

D

Automatic rescaling means that images are produced, regardless of the amount of exposure, with:

A. uniform size and shape.

B. uniform contrast and density.

C. variable size and shape.

D. variable contrast and density.

B

A look-up table is not used as a reference to:

A. set appropriate kilovoltage peak and milliampere-seconds values.

B. evaluate raw luminance values.

C. correct luminance values.

D. provide appropriate brightness and contrast.

A

Changing the slope of the look-up table graph will increase or decrease:

A. density.

B. the number of pixels.

C. the matrix size.

D. contrast.

D

If all of the shades were left in an image after processing, the contrast would be:

A. too low.

B. too high.

C. sufficient.

D. unaffected.

A

Changing the steepness of the exposure gradient:

A. varies density.

B. determines spatial frequency.

C. controls image contrast.

D. has no effect on the image.

C

Focal spot and OID affect image sharpness _____ imaging.

A. only in film/screen

B. only in digital

C. in both film/screen and digital

D. in neither film/screen nor digital

C

The improper algorithm application may result in:

A. enhanced contrast.

B improved resolution.

C. repeat examinations.

D. degradation of the image.

D

The more manipulation of the image, the greater the:

A. amount of resolution.

B. loss of information.

C. quality of the image.

D. radiologist manipulation

B

Amplification of the frequencies of the areas of interest is known as:

A. algorithm application.

B. center enhancement.

C edge enhancement.

D. masking.

C

Suppressing frequencies in the areas of interest is known as:

A. algorithm application.

B. center enhancement.

C. edge enhancement.

D. masking.

D

Low-pass filtering is also known as:

A. evening.

B. smoothing.

C. masking.

D. marking.

B

High-pass filtering is useful for enhancing:

A. small structures.

B. fine bone tissues.

C. large bony structures.

D. organs and soft tissue.

D

Averaging the frequency of each pixel with surrounding pixel values to remove high-frequency noise is called:

A. high-pass filtering.

B. low-pass filtering.

C. edge enhancement.

D. noise enhancement.

B

Image level parameters control image:

A. brightness.

B. darkness.

C. contrast.

D. density.

A

Window width controls the ratio of black and white, also known as:

A. window.

B. level.

C. contrast.

D. matrix.

C

Excessive light entering the eye when viewing an image is known as ______ glare.

A. veil

B. window

C. level

D. none of these

A

An image manipulation process that fills in the background so that it is darkened is known as:

A. window.

B. level.

C. shuttering.

D. collimation.

C

The image reader scans and reads the image from the:

A. back edge of the imaging plate to the opposite end.

B. leading edge of the imaging plate to the opposite end.

C. right to left side.

D. left to right side.

B

The process of joining two or more images into one continuous image is known as image:

A. connection.

B. annotation.

C. stitching.

D. lacing.

C

The workstation function that allows selection of preset terms or manual text input is termed image:

A. connection.

B. annotation.

C. stitching.

D. lacing.

B

Input of annotation for identification of the patient's left or right side:

A. should take the place of the technologist's anatomy markers.

B. should be used in conjunction with the technologist's markers.

C. eliminates the need for any other type of anatomy markers.

D. none of the above.

B

Magnification of the entire image at the workstation is termed:

A. image intensification.

B. macroradiography.

C. enlargement.

D. zoom

D

Proper patient demographic input ensures:

A. multiple records on each patient.

B. linking of all the patient's files.

C. multiple versions of the patient's name.

D. an increase in the amount of data tracking.

B

The ability to send images to local network stations can be accomplished using the:

A. archive query.

B. patient demographic input.

C. QC query.

D. manual send function.

D

Proper patient demographic input is the responsibility of the:

A. technologist

B. QC manager.

C. radiologist.

D. transporter.

A

An archive query retrieves images from the PACS based on any of the following except:

A. patient name.

B. examination date.

C. anatomical area.

D. technologist anatomical number.

D

The shape of the histogram is anatomy specific.

True

False

True

Image aliasing is similar to the moiré effect caused by grid error.

True

False

False

Automatic rescaling can be substituted for appropriate technical factors.

True

False

False

Basic workstation functions include contrast manipulation, edge enhancement, and smoothing.

True

False

True

Shuttering removes the dark exposed border, reducing the amount of information to be stored.

True

False

False

Historical study of patient examinations can be accomplished through the manual send function.

True

False

False

No matter where the orientation stickers or labels exist on a digital cassette, the image will display correctly.

True

False

False