processing terms Flashcards

1
Q

raw data

A

is the exposure information prior to any processing algorithms
-raw data is converted into digital data using the analog to digital converter 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

quantization

A

assigns each pixel number
-each number has an assigned grayscale value.
- when does it happen: the same time as the analog to digital conversion. ( digital part is the number)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

bit depth

A

is the number of shades of gray that can be used to define each pixel higher, the bit depth higher the amount of information 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

grayscale 

A

Digital term for scale of contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is a histogram

A

A graphical display of the pixel intensity distribution for a digital image. Frequency of recorded exposure values. 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are VOI

A

values of interest
they are stored in histogram models

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what to VOI determine

A

The range of the histogram data set that should be included in the displayed image 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

look up table

A

it allows gray scale, values in the recorded image to be remapped to new values to improve the final image in someway, such as appropriate brightness and contrast.
LUT’s are specific to anatomic areas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

LUT is the controller for

A

digital contrast ***

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

rescaling

A

corrects the appearance of an image one small exposure Errors are present.
-compensates for minor over exposure. Errors made by the tech. 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is a dead pixel? 

A

A pixel with a malfunction or sensor error. Able to be seen on technologist panel. 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

dead pixel correction

A

using a software technique, dead pixels are identified in the matrix and then removed from all subsequent images. 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

flat fielding

A

Dead pixels are removed from the matrix by making a mask of the dead pixels. 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

edge ethancement

A

increases the contrast along the edges of the structures.
- It improves the visibility of details if excessive edge enhancement is used, it can cause a halo artifact around edges.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

equalization 

A

process by which soft tissue and bone are enhanced so all the information within a region of interest can be seen
example: chest images anatomy above, and below the diaphragm can be seen
**It can’t correct for severe under or over exposure 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

smoothing OR noise, suppression, low pass, filtering

A

is used to mask the quantum noise in an image remove random noise areas.
disadvantage : smoothing causes a loss of spatial resolution
Smoothing can’t correct for significant under exposure *

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

post processing

A

when the image appears on the screen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

windowing

A

ability to alter, the brightness and contrast of a digital image following processing.
It is done post processing. 

19
Q

window width

A

adjust image contrast in the grayscale representation of the tissue.
- wider width
-narrow width 

20
Q

wider width

A

Low contrast/long scale, (more shades of gray)
-elephants are wide**

21
Q

narrow width

A

High contrast, short scale, more black and white.

22
Q

region of interest

A

A technologist can utilize it during post processing to enhance certain areas of the image
-the ROI determines the average pixel value

23
Q

shuttering

A

removes white borders around the radiograph because it can cause eye, fatigue and radiologist, trying to read the image 

24
Q

electronic cropping or masking

A

crop and image afterwards
shouldn’t be done!!!
- electronic cropping should never be used to crop out anatomy.
- can use it to remove artifacts or errors (scratch on cr plate or a mat next to them)

25
Q

image inversion

A

used often for visualizing tubes or lines, -inverting the image of swap, white/block that is normally seen 

26
Q

image subtraction

A

Technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment removes the bones to look for blockages or obstructions. 

27
Q

annotation

A

writing on the image
- upright/ erect
-supine

28
Q

cropping

A

post exposure
removes areas of the image should not be used in place of collimation at the time of the procedure 

29
Q

Image stitching

A

The CR processing system uses a stitching application to connect the two images into one for the radiologist to view. Example.) scoliosis. 

30
Q

Display monitors 

A

Digital images are displayed on LCD (liquid crystal display monitors)
-The quality of the image and accuracy of the interpretation depends on the number of factors;
-Spatial resolution
-Luminance
-Contrast resolution 

31
Q

Monitor viewing conditions

A

Lumens is the amount of light that is emitted from the monitor lumens is important and detecting structures with low contrast, the brighter, the image, the better the contrast resolution 

32
Q

Monitor viewing angle 

A

refers to the maximal angle at which a display monitor can be viewed with acceptable visual performance
- radiologists should be reading it straight on!

33
Q

Lighting for monitors

A

ambient lighting, refers to the overall illumination of a room, natural light fluorescent light and lamps
-glare from lighting to bright can lead to an accurate reading, and eye fatigue -glare and reflections on the screen will cause the eyes to refocus. Each time vision is passed over the Brightened area
- remove lights!!

34
Q

Display monitor quality control test

A

radiology display monitors are checked as part of the quality control program
- a photometer measures the lumens of the monitor as a part of a quality control test
-SMPTE test pattern *

35
Q

luminance is measured in

A

candela per square meter

36
Q

display monitor what light comes off

A

luminance

37
Q

PACS stands for

A

Picture archival in communication system
- sends x rays to PACS. epic

38
Q

DICOM

A

Digital imaging and communications in medicine
enables the integration of scanners servers, workstations, printers in network hardware for multiple manufacturers 

39
Q

Teleradiology

A

The practice of a radiologist interpreting medical images, while not physically present in the location where the images are generated 

40
Q

HIS

A

hospital information system,
which is patient information stored in the hospital database 

41
Q

RIS

A

radiology information system
Radiology, modality, work list, and radiology orders 

42
Q

EMR

A

electronic medical record means entering a patient’s chart digitally
- never go looking into a patients chart unless it’s your patient

43
Q

EHR

A

electronic health record
includes information from various healthcare providers 

44
Q

signal to noise ratio

A

good parts of x rays signals
noise- bad grainy
-ideally high signal, low noise
-compares the good parts of your picture to the bad parts