Medical Imaging: X-Ray

Question 1

True Positive

Answer 1

test detects something that is really there

Question 2

False Positive/Type I Error

Answer 2

test detects something not really there

Question 3

True Negative

Answer 3

test detects nothing, and nothing is there

Question 4

False Negative/Type II error

Answer 4

test detects nothing, but there is something there

Question 5

Sensitivity

Answer 5

test’s ability to identify the presence of a condition

Question 6

Specificity

Answer 6

test’s ability to identify the absence of a condition

Question 7

Conventional Radiographs are also

Answer 7

plain films or x-rays

Question 8

Conventional Radiographs are ___-order diagnostic modality

Answer 8

first-order

Question 9

Advantages of x-rays

Answer 9

• time & cost efficient
• Non-invasive
• Low risk
• Good for screening

Question 10

Disadvantages of x-rays

Answer 10

poor sensitivity (presence of pathology)

Question 11

What is attenuation?

Answer 11

Reduction in strength/density of x-ray beam as it passes through a medium

Question 12

What is Permeability?

Answer 12

the degree to which x-ray beams can pass through a substance to reach the film plate

Question 13

What is radiodensity?

Answer 13

an object’s x-ray absorption capacity

Question 14

What is an x-ray absorption capacity based on?

Answer 14

composition
density
thickness

Question 15

What is the relationship between radiodensity of object vs radiographic film?

Answer 15

inversely related

Question 16

Highly radiodense objects result in more or less radiodensity on film?

Answer 16

less- more white

Question 17

Radiolucent means

Answer 17

low attenuation

Question 18

Radioopaque means

Answer 18

high attenuation

Question 19

What shade of gray would fat appear on film?

Answer 19

gray-black

Question 20

What shade of gray would bone appear on film?

Answer 20

gray-white

Question 21

What shade of gray would soft tissue appear on film?

Answer 21

gray

Question 22

Soft tissue also has the same radiodensity to what?

Answer 22

Water, difficult to look at w/o contrast media

Question 23

What color would contrast media appear on film?

Answer 23

white

Question 24

What color would heavy metals appear on film?

Answer 24

solid white

Question 25

How many views are ideal for looking at x-rays?

Answer 25

at least two views | ideally at 90 deg angle to each other

Question 26

Photographic qualities refer to what of an image?

Answer 26

visibility

Question 27

What is density refer to of an image?

Answer 27

amount of blackening on the radiograph | affected by distance, exposure time, and radiation quality

Question 28

What is contrast refer to of an image?

Answer 28

differences between adjacent tissue densities | affected by material density, composition, and radiation quality

Question 29

Geometric qualities refer to what of an image?

Answer 29

clarity

Question 30

What is detail refer to of an image?

Answer 30

sharpness or resolution | maximized by placing structure closest to film plate

Question 31

What is distortion caused by in an image?

Answer 31

distance b/t beam source, patient, and image receptor | misalignment/position issues

Question 32

Magnification

Answer 32

structures further from film appear larger

Question 33

Foreshortening

Answer 33

image appears shorter than actual structure

Question 34

Elongation

Answer 34

image appears longer than structure

Question 35

Image is sharply define and less distorted when structures are closer or farther to film plate?

Answer 35

closer

Question 36

AP/PA radiographs are named based on what?

Answer 36

Direction the beam traveled through patient - PA: posterior to anterior - AP: anterior to posterior

Question 37

Lateral/Oblique views are named for the side farther or closer to film plate?

Answer 37

closer

Question 38

(A)ABCs of Radiology

Answer 38

``` Adequacy Alignment Bone Cartilage Soft Tissue ```

Question 39

Adequacy criteria

Answer 39

- bony structures well visualized - appropriate exposure - joints above and below area of concern visualized

Question 40

Alignment characteristics

Answer 40

- gross bone size - number of bones - shape and contour of cortical outline - joint position and alignment

Question 41

Bone characteristics

Answer 41

- cortical margin dense - cancellous bone + medullary cavity lower density - weight-bearing surfaces higher density - "washed-out" suggests osteoporosis - excessive sclerosis suggests arthritis/RA

Question 42

Cartilage characteristics

Answer 42

- joint space width - subchondral bone - joint margins - epiphyses and growth plates in children

Question 43

Soft Tissue characteristics

Answer 43

- gross size of musculature - outline of joint capsules - periosteum