Physics 2

Question 1

What are the 5 imaging modalities?

Answer 1

Radiography
Ultrasonography
Nuclear scintigraphy
Computed tomography
Magnetic resonance imaging

Question 2

What are Roentgen (imaging) signs?

Answer 2

A visual clue or signal that is produced by a pathologic change of tissue and may be detected in a medical image

Question 3

What are the 6 observations made with Roentgen signs?

Answer 3

Size
Shape
Margin
Opacity
Number 
Location

Question 4

What are the 5 opacities?

Answer 4

Gas
Fat
Soft tissue = fluid
Mineral
Metal

Question 5

What are some additional imaging signs?

Answer 5

Function
Alignmeent
Through-transmission
Contrast uptake

Question 6

What are the 5 diagnostic pitfalls of DI?

Answer 6

Error rates are high
Interpretation is the result of complex perceptual mechanisms
Previous experience provides a large portion of perceived image
Attitude affects interpretation
Multiple readings reduce errors

Question 7

What are some visual disabilities of DI (5)?

Answer 7

Dark adaptation 
Glare
Length, angle, size are hard to 'see'
Mach phenomenon
Contrast background effect

Question 8

What is the Mach phenomenon

Answer 8

Mach lines are false white or black lines that appear at sharp boundaries. These optical illusions enhance boundaries but can mimic lesions

Question 9

What is the contrast background effect?

Answer 9

The eye is a poor judge of absolute brightness–based on the background color, the shade of an object can appear lighter/darker than it really is

Question 10

What is the difference between vision and perception?

Answer 10

Vision = what the eye sees
Perception = what the brain sees
Previous experience influences your perception; visual signals are compared to memory and most likely explanations are ‘seen’

Question 11

Radiographs

Answer 11

Images of shades: 2-dimensional contours of 3-dimensional objects
Complex summations of several categories of shades; perception of contours is primary visual mechanism used to ‘see’ radiographs

Question 12

Contours

Answer 12

Perceived when there is change in brightness or color between adjacent objects; can occur without changes–results from mental completion of partial lines to form something expected

Question 13

T/F: False masses (even kidneys) can be created by loops of bowel

Answer 13

TRUE

Question 14

What are the 6 key concepts to radiographic interpretation?

Answer 14

Opacity
Summation
Silhouetting
Orientation
Conventions
Systematic approach

Question 15

What are the 5 opacities?

Answer 15

Gas opacity
Fat opacity
Fluid = soft tissue opacity
Bone = mineral opacity
Metal opacity

Question 16

What determines the opacity (5 factors)?

Answer 16

Molecular structure
Atomic elements
Thickness
Density
Manifested as "shades of gray" on film or computer monitor

Question 17

What is an analog gray scale?

Answer 17

Continuous scale from black to white

Question 18

Blackest images = ___; whitest images = ____.

Answer 18

gas;

dense bone to metal

Question 19

What does difference in opacity determine?

Answer 19

Contrast

Question 20

Summation

Answer 20

An area of increased radiopacity (‘whiteness’) occurring when two OVERLAPPING objects are in the path of the x-ray beam and are NOT in contact with one another

Question 21

Silhouette sign

Answer 21

Margins of 2 objects cannot be distinguished because of similar opacity and margins are IN CONTACT

Question 22

What must you consider when interpreting radiographs (5)?

Answer 22

Technical characteristics
Normal or normal anatomic variation or age-related change
True lesions: incidental or clinically relevant
Conclusions about findings
Recommendations or the ‘next step’

Question 23

T/F: A systematic approach to interpretation is fundamental

Answer 23

TRUE

Question 24

How are radiographic projections named?

Answer 24

Named according to the direction of the primary x-ray beam as it penetrates the area of a body–from point of entrance to point of exit

Question 25

How are oblique/special radiographic views named?

Answer 25

Should be named in the same method used in naming the standard views
Can add angles of obliquity
Angle, measured in degrees is added after the first directional designation
Clinical jargon can be added, and any special positioning should be mentioned