MSK Radiology Flashcards

1
Q

The denser the object … the more/less radiation bros red so the image appears lighter/darker ?

A

The denser the object , the more radiation is absorbed , so the image appears whiter.

  • for example bone.
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2
Q

What are the advantages of using X-rays ?

A

1) relatively inexpensive

2) very quick to obtain

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3
Q

What are the disadvantages of using X-rays ?

A

1( transmission of radiation to the patient

2) poor soft tissue contrast resolution - so they are not useful for imaging soft tissue

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4
Q

What are the initial imaging choice for skeletal trauma ?

A

X-rays , for example they are used for fractures and joint dislocations

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5
Q

For what type of chronic bone pathologies and joint pathologies are x rays used to image ?

A
  • osteomyelitis
  • chronic arthritis (rheumatoid , osteoarthritis)

-

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6
Q

What structure that forms part of the long bone appears radiolucent on a n X-RAY image ?

A

Articular cartilage - it appears as a joint space

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7
Q

Define a fracture

A

A complete or incomplete break in the continuity of the bone

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8
Q

What are the 8 types of fractures ?

A

1) transverse
2) linear
3) oblique non displaced
4) oblique displaced
5) spiral
6) green stick
7) comminuted
8) compression fracture

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9
Q

Describe the nature of a transverse fracture

A

Break crosses the bone at a right angle to the long axis of the bone

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10
Q

Describe the nature of a linear bone fracture

A

Fracture line passes in parallel to the long axis of the bone

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11
Q

Describe the nature of an oblique non-displaced fracture

A

Fracture line is at an oblique (acute or obtuse) angle to the long axis . But bone has not been displaced

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12
Q

Describe the nature of an oblique displaced fracture

A

Fracture line is at an oblique angle to the long axis of the bone - but the bone has been displaced

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13
Q

Describe the nature of a spiral fracture

A

This fracture is easily confused with an oblique fracture on an X ray , but in a spiral fracture , the fracture spirals round in multiple places. You need to generate a 3G image of the fracture to confirm it is a spiral and not an oblique fracture.

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14
Q

Describe nature of compression fracture

A
  • these occur in cancellous bone when an axial load comprises the bone beyond its limit
  • most commonly occur in the lumbar vertebrae - you can see that the bone is crushed
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15
Q

Describe the nature of green stick fractures

A
  • these occur ONLY in children
  • this is an incomplete fracture in which the bone bends and cracks on only ONE side of the cortex.
  • so bone is NOT split into two.
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16
Q

What is another type of fracture - other than green stick fractures that occurs ONLY in children ?

A

Epiphyseal separation fractures

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17
Q

Describe the nature of epiphyseal separation fractures

A
  • this occurs when the fracture line extends through an infused growth plate - thereby spreading the epiphysis from the metaphysis
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18
Q

Describe the nature of a communited fracture

A

This occurs when the bone cracks into several fragments . This is often as a result of trauma.

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19
Q

‘ slipped upper femoral epiphysis’ is an example of which type of fracture ?

A

Epiphyseal separation fractures

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20
Q

Describe the nature of slipped upper femoral epiphysis

A
  • this often occurs in overweight adolescent boys during their rapid growth spurt
  • it is where the epiphysis of the femur slips off from the femoral neck.
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21
Q

What occurs to the epiphyseal growth plates as a child grows up ?

A
  • the growth plates become thinner , eventually disappearing and become closed.
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22
Q

During bone development , where is the primary ossification centre found ?

A

Centre in the diaphysis of long bones.

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23
Q

During bone development , where would you find the secondary ossification centres ?

A

Epiphysis

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24
Q

What hormone would promote cellular proliferation in the growth plate during development ?

A

Growth hormone

25
Q

What hormones could result in a reduction of cell division in the proliferation zone of the growth plate during development ?

A

1) deficiency of thyroid hormone
2) excess corticosteroids
- this leads to growth retardation

26
Q

What are the short bones in the wrist called ?

A

Carpal bones

27
Q

What are the short bones in the ankles called ?

A

Tarsal bones

28
Q

Give an example of a bone which is not ossified at birth and ossify gradually from birth onwards ?

A

Carpal bones in the wrist

29
Q

What factor can help estimate the maturity of the child’s MSK?

A

bone age - by assessing the degree of ossification of the carpal bones and the maturation of the growth plates of long bones

30
Q

What may a significant difference between a child’s bone age and chronological age indicate ?

A
  • early /delayed puberty
  • growth hormone deficiency
  • hypo/hyperthyroidism
  • malnutrition
31
Q

What are the 3 phases of fracture repair ?

A

1) inflammatory phase
2) reparative phase
3) remodelling phase

32
Q

What occurs during the inflammatory phase of fracture healing ?

A
  • haematoma forms
  • tissue death
  • inflammation by granulocytes
  • callus has NOT yet formed
33
Q

How long does the inflammatory phase last ?

A
  • hours to days
34
Q

What occurs during the reparative phase ?

A

1) procallus formation
2) soft callus formation ( fibrocartilaginous)
3) hard callus formation

35
Q

How long does the reparative phase lasts?

A

Days to weeks

36
Q

What occurs during the remodelling phase ?

A

Replacement of hard callus with mature bone

37
Q

How long does the remodelling phase last?

A

Months to years

38
Q

What does it mean by the ‘ radio graphic union ‘

A

Fracture line eventually becomes completely obscured

39
Q

What does CT stand for ?

A

Computed tomography

40
Q

What is another term for CT scans ?

A

CAT scanning ( computerised axial tomography)

41
Q

What are the advantages of CT scans ?

A

1) much better when producing images for soft tissues
2) excellent resolution for images and thin slices which means it can be used in guiding injections , bioposies and aspirations in REAL time
3) 3D images can be made ( this can help identify spiral fractures better)
4) very quick to do , but not as quick as X rays

42
Q

What are the disadvantages of CT scanning ?

A

1) patient may be very nervous and move a lot during CT scan , this can produce motion artefact which can distort image
2) exposure to much more radiation than plain X rays
3) severely obese patients cannot always be accommodated with the scanner

43
Q

What are most CT scans performed with ?

A

Intravenous contrast - however , some patients can be allergic to this contract - which can cause anaphylaxis

44
Q

In what units is the density of body tissues measured in for CT scans ?

A

Hounsfield units( HU)

45
Q

What is the density of water in HU ?

A

0 HU

46
Q

Anything less dense than water or equal density to water will appear what colours?

A

Black

47
Q

Anything denser than water will appear what colour ?

A

White or grey

48
Q

What colour would soft tissue appear ?

A

Grey

49
Q

What colour would bone appear ?

A

White

50
Q

What colour would air , Fat and water appear ?

A

Black

51
Q

What is the best method to image soft tissues ?

A

MRI scans

52
Q

What are advantages for MRI scans ?

A

1) good imaging for soft tissue
2) no radiation
3) multiplanar images

53
Q

What are disadvantages of MRI scans ?

A

1) expensive
2) poor micro architecture of bone

3 any metal framework in the body means patient may not be eligible for MRI scan

4) takes much longer - patient more likely to move
5) claustrophobic patients may not like the scanner because it like a tunnel and very noisy
6) patients with pacemakers cannot do MRI scans because if can malfunction it

54
Q

How does an ultrasonography work ?

A
  • uses high frequency sound waves to produce images. The sound waves produced by a transducer and travel through the patient. Tissue and tissue planes then deflect the waves back to the transducer and these are then analysed to create an image.
55
Q

What are the advantages for ultrasonography ?

A

1) non invasive
2) does not use radiation
3) can image soft tissues very well
4) can be used to identify haemotomas , be used for target injections and perform aspirations on joints

56
Q

What are the disadvantages of ultrasonography ?

A

1( highly dependant on a skilled operator for interpretation of images

2) resolution of deep tissues is poor
3) limited suitability for bone imaging

57
Q

What is nuclear medicine?

A

Uses radioisotope labellebed biologically active drugs that are administered to the patient to serve as a marker for biological activity

  • used to assess areas of metabolically active bone such as when trying to localise metastatic diseases , healing fractures , osteomyelitis
58
Q

What are disadvantages of nuclear medicine ?

A

1) radiation is ionising which could lead to DNA damage.
2) care should be taken for both healthcare workers and patients from ironing radiation for eg healthcare workers should wear lead aprons when dealing with radiation.