intro to MSK imaging

Question 1

What 3 things are required for X-ray?

Answer 1

1. beam source
2. patient
3. receptor - x ray film or digital receptor

Question 2

waht is an x ray (radio graph)?

Answer 2

• radiograph is a recorded image of an antomic part acquired by the passage of xrays through the body. a conventiona lradiograph is one made without contrast enhancement or other equipment modification

Question 3

What is radiation?

Answer 3

radiation is energy that is transmitted through space or matter

the different forms of energy used in medicine include: mechanical, electircal, thermal, nuclear, electromagnetic

Question 4

does MRI have radiation?

Answer 4

no

Question 5

What is the average dose of radiation exposure from
Whole body CT scan?
mammogram?
chest radiograph?
bone densitometry (DEXA)?
x ray security screening?

Answer 5

CT: 10 mSV
mammogram: 0.7 mSv
chest radiograph: 0.1 mSv
DEXA: 0.01mSv
x-ray security: 01 usV

DEXA is really high!!!

Question 6

What is radiodensity?
What is it determined by?

Answer 6

• refers to amount ofradiation an object absorbs from the x-ray beam
  determined by:
• composition -effective atomic number and volume density
• thickness
• the greater an objects effective atomic number, volume density and or thickness the greater its radiodensity

Question 7

What is lucency?

Answer 7

• lucent - clear, allows passage of light
  radiolucent:
• refers to how much of the beam is allowed to pass through
• appears darker

Question 8

what is opacity?

Answer 8

not transparent, does not allow passage of light

Question 9

What is radiolucent?

Answer 9

radiolucent:
- refers to how much of the beam is allowed to pass through
- appears darker

Question 11

what is radio-opaque?

Answer 11

• refers to how much of the beam is absorbed and does not pass through
  -appears lighter

Question 12

What tissue is the most radiodense natural tissue of the body?

Answer 12

bone

Question 13

Talk about the radiolucent/radio-opaque scale?

Answer 13

Question 14

radio graph evaluation (the abcs)

Answer 14

• alignment
• bone density
• cartilage spaces
• soft tissue

Question 15

4 things with radio graph alignment?

Answer 15

1. size of bone
2. number of bone
3. shape and contour of bone
4. bone and joint position

Question 16

3 things with radio graph bone density?

Answer 16

1. general bone density
2. focal bone density
3. trabecular alteration

Question 17

radio graph cartilage space. what are you looking for?

Answer 17

1. joint space
   - width
   - symmetry
2. subchondral bone
   - contour
   - density

Question 18

radio graph bone density. What are you looking for?

Answer 18

1. gross musculature
2. joint capsule
   - increase volume
   - fat pad sign
3. periosteum

Question 19

what is a fat pad sign in the soft tissue of a radio graph indicative of?

Answer 19

fracture

Question 20

what are the different positions you can ahve for a radiographic projection?

Answer 20

• AP
• PA
• lateral
• AP or PA oblique
• AP or PA axial
• tangential
• transthoracic
• inferosuperior
• superoinferior
• plantdorsal (PD)
• dorsoplantar (DP)
• lateromedial
• mediolateral
• submentovertical
• verticosubmental
• carnicaudal
• orbitoparietal
• parieto-orbital

Question 21

how many view should you look at in an imaging?

Answer 21

minimum 2

Question 22

Answer 22

Question 23

What is the first choice of imaging for an evaluation for frank neurological signs (CNS and PNS)?

Answer 23

MRI

Question 24

What is the first choice of imaging for evaluation of spinal pathology?

Answer 24

MRI

Question 25

What is the first choice of imaging for internal joint derangments (ligaments, meniscii, articlar cartilage, labral pathology)?

Answer 25

MRi

Question 26

What is the first choice of imaging for inflammaotyr arthritis?

Answer 26

none - MRI, CT and NM (bone scan) all rate low

Question 27

What is the first choice of imaging for evaluation of soft tissue injury (muscle injuries, tendon pathology, calcified bursitis)

Answer 27

MRI

Question 28

What is the first choice of imaging for osteomyelitis

Answer 28

MRI or NM (bone scan)

Question 29

What is the first choice of imaging for fluid collections or infections in joints or extraarticular sfot tisseus; unexplained soft tissue mass

Answer 29

MRi

Question 30

What is the first choice of imaging for osteonecrosis

Answer 30

MRi

Question 31

What is the first choice of imaging for complicated fractures

Answer 31

CT

Question 32

What is the first choice of imaging for suspected stress, occult fracture

Answer 32

NM (bone scan)

Question 33

What is the first choice of imaging for complicated disease processes or finding unexplained by more conservative tests

Answer 33

none - all rate low

Question 34

What is the first choice of imaging for evaluation of possible neoplasm detected on conventional radiographs

Answer 34

MRi

Question 35

What is the first choice of imaging for determiningskeletal distribution of neoplasms or other multifocal skeletal disease

Answer 35

NM (nuclear medicine - bone scan)

Question 36

What does MRI image best?

Answer 36

- excels in display of soft tissue detail - sensitive for detecting changes and varitions in bone marrow (diagnosing bone tumors, stress fractures, avascular necrosis) - replaced arthroscopy as in detection of meniscal tears - best modality for eval of disk hernations and other nerve root impingements - ability to stage neoplasms in bone and soft tissues - evaluate the extent of tissue invasion before surgery (more sensitive than bone scan fordetecting bone metastases)

Question 37

What is a CT scan best for?

Answer 37

- subtle fractures/complex fractures - detailed evaluation of degenerative changes (spinal arthritic changes) - first imaging chose in sesriou strauma bc multiple injures to both osseous and soft tissue structures can be determined from one imaging series - evaluation of spinal stenosis (CT myelography) - evaluation of loose bodies in a joint - accurate measurements of osseous alignment in any plane

Question 38

why is sometimes a CT scan chosen over MRI?

Answer 38

- less time consuming than MRI or ultrasound - usually less expensive - less problematic for patients with claustrophobia

Question 39

would you use an x ray for rib or hip fracture?

Answer 39

NO