Image Processing and Display
What term in digital imaging is used to describe the process the computer uses to produce a uniform brightness and contrast regardless of the exposure?
Automatic rescaling
What should a radiologic technologist do when the optical path of the computed radiography imaging system is dirty due to dust?
Call a professional service.
Which process helps reduce the heel effect on digital radiographic images?
Collimation
What is the function of window width?
Controlling contrast
What is a standard method of data storage that was developed by ACR and NEMA?
DICOM
Which term is used to describe the random scattering of light on a digital display device
Diffuse reflection
Which term is used to describe the random scattering of light on a digital display device?
Diffuse reflection
What is the purpose of image compression in digital radiography?
Easy file transfer
Which postprocessing function increases noise that is already present in an image?
Edge enhancement
The radiologic technologist can change how many shades of gray are visible by using what postprocessing technique?
Window and level
Which process helps to increase the gray scale visibility of a radiographic image?
Window and level adjustment
What are the post-processing functions associated with the fluoroscopic technique? Select all that apply.
Windowing Spatial filtering Image annotation
Where would a radiologic technologist most likely encounter the RIS?
Worklist in the radiographic exam room
What effect is observed in a digital radiographic image after window and level adjustment?
Amplified image contrast
Which is a characteristic histogram of cervical spine?
1
What is the acceptable lossless compression for a digital radiographic image?
3:1
An x-ray image shows the presence of dark and bright areas upon exposure to raw x-ray beams. Which process helps correct this defect in the radiographic image?
Flat fielding
Offset images and gain images are automatic calibration images designed to make the response of the image receptor uniform. What are these preprocessing calibration techniques identified as?
Flatfielding
Which preprocessing procedure converts an undesired effect, shown in image A, into a corrected form, as shown in image B?
Flatfielding
____________ spatial frequency indicates better spatial resolution, which is good to show _____________ objects.
Higher; smaller
Which postprocessing technique is helpful in rotating a digital radiographic image of the wrist, horizontally or vertically, as shown in the image?
Image Flip
Liquid crystal displays (LCDs) are designed to better reduce the influence of ambient light on what image characteristic?
Image contrast
A radiologic technologist finds it difficult to identify a patient's disease after seeing the radiographic film, which shows the bones as white in color. Which process helps the radiologic technologist change the color of the bones to black in the radiographic image?
Image inversion
Which postprocessing technique is used to manipulate the radiograph as seen in the image?
Image inversion
What phenomenon can be troublesome when switching from high-dose to low-dose techniques, such as switching from digital subtraction angiography (DSA) to fluoroscopy?
Image lag
Aperture ratio is a measure of what characteristic of liquid crystal displays (LCDs)?
Image luminance
What is the name of the preprocess that occurs to correct for dead pixels?
Interpolation
Which is true regarding partitioning in digital radiography? Select all that apply.
It helps in proper separation of the images. It results in proper collimation of the images. It helps in proper projection of multiple fields onto a single imaging plate.
What is a histogram?
It is a plot between frequencies of occurrence versus the digital value of each pixel.
What preprocessing actions are automatically applied with most systems? Select all that apply.
Lag correction Noise correction Pixel interpolation
The lower jaw and associated teeth are radiographed in a patient complaining of a toothache. Which post-processing technique is useful for improving the visibility of the minutest roots of the teeth?
Magnification
Which process helps to improve the visibility of a digital image?
Magnification
Which association provides the guidelines to transfer a radiographic image to various DICOM-compatible display devices without altering its gray scale?
National Electrical Manufacturers Association (NEMA)
Name the principle components of a picture archiving and communication system (PACS). Select all that apply.
Network Display system Storage system Acquisition system
The Radiology Information System (RIS), which is responsible for functions including message and mail utilities, calendar reporting, storage of text data, and financial accounting and planning, is the information management and database portion of what system?
PACS
How can the effects of a patient's undesired motion during image acquisition of a subtracted image be rectified after imaging has occurred?
Pixel shift
What postprocessing technique would be used to reregister an image to correct for patient motion?
Pixel shift
What is used in quantitative radiography for detection of some pathology types?
ROI
Which provides the optimal viewing conditions for a radiographic study?
Radiologist interpretation room
Quantitative radiology, which is finding application in bone mineral assay, calcified lung nodule detection, and renal stone identification, requires what process to determine the numeric value of pixels to help in diagnosis?
Region of interest identification
What is the best thing a radiologic technologist can do in the event that an imaging plate is substantially scratched?
Replace the imaging plate.
Which postprocessing function helps with viewing small anatomical parts by removing image noise?
Smoothing
Which position is suitable for the best viewing of a radiographic image without reduction in the contrast?
Straight towards the device
Which is the application that will improve image contrast?
Subtraction
Why is the window level adjusted during postprocessing of an image?
To control image brightness
How are signals created in computed radiography converted to a viewable image?
Using an ADC
