Ch 4 Foreign Bodies

Question 1

What is a foreign body?

Answer 1

Anything inside the body that originated outside of the body

Question 2

List examples of organic, inorganic + metallic foreign bodies?

Answer 2

Organic:
-Plant material (thorn, wood)
-Animal products (bee stinger)

Inorganic:
-Glass, gravel, plastic, pencil lead, graphite

Metallic:
-Wire, needle, fish hooks

Question 3

Differentiate b/w radiolucent + radiopaque?

Answer 3

Radiolucent:
-Tissue or material that allows the transmission of x-rays + appears DARK on a radiograph

Radiopaque:
-Tissue, contrast or material that attenuates/blocks radiation + appears BRIGHT on a radiograph

Question 4

___ is the m/c used imaging modality for the evaluation of foreign bodies in the ER?

Answer 4

Radiography

Question 5

Radiographic imaging relies on the ___ of the foreign body?

Answer 5

Density

Question 6

Does radiography have a high or low sensitivity for radiopaque objects (gravel, glass, metal)?

Answer 6

High (98%)

Question 7

Does radiography have a high or low sensitivity for radiolucent objects (wood, plastic, organic materials)?

Answer 7

Low (15%)

Question 8

___ can detect foreign bodies with both high sensitivity + specificity?

Answer 8

U/s

Question 9

Which probe do we use to evaluate FBs?

Answer 9

High frequency linear probe (remember to be as perpendicular to the FB as possible)

Question 10

What should we do before beginning to scan the pt?

Answer 10

-Obtain thorough pt history
-Use palpation techniques
-Review x-rays + previous imaging

Question 11

List 2 tips that help with scanning superficial lesions?

Answer 11

-Use stand off pad or a thick amount of gel
-Use water bath

Question 12

What 4 things must we evaluate when assessing a FB?

Answer 12

-Composition (organic, metal, inorganic)
-Location
-Age
-Appearance

Question 13

List 3 helpful artifacts when scanning a FB?

Answer 13

-Shadowing
-Reverb
-Comet tail (metallic glass)

Question 14

List the dates for acute, intermediate + chronic phases?

Answer 14

Acute: < 3 days
Intermediate: 3-10 days
Chronic: > 10 days

Question 15

List the SFs for an acute, intermediate + chronic aged foreign body?

Answer 15

Acute:
-Echogenic structure with shadowing (air)
-Hypoechoic halo around FB within 24 hours (inflammation)

Intermediate:
-Fluid now replaces air
-Pronounced hypoechoic halo
-Hyperemic

Chronic:
-“Walling off”
-Granular material develops + encapsulates the FB
-May have shadow

Question 16

Which stage has a pronounced hypoechoic halo + fluid?

Answer 16

Intermediate

Question 17

Which stage has granuloma formation + shadowing?

Answer 17

Chronic (this is how the body keeps infections from spreading)

Question 18

Which stage appears echogenic with air?

Answer 18

Acute

Question 19

What is a granuloma?

Answer 19

-Tiny cluster of white blood cells and other tissue
-Due to infections, inflammation, irritants or foreign objects

Question 20

List 4 limitations of u/s when imaging foreign bodies?

Answer 20

-Operator dependence
-Size of FB (<2mm)
-Location of FB (deep or posterior to bone/air)
-False positives (calcifications, scar tissue, fresh hematomas, trapped air in soft tissue)

Question 21

___ is the m/c complication of a FB?

Answer 21

Infection

Question 22

___ can be used for guidance in the removal of a FB?

Answer 22

U/s