MSK Radiology

Question 1

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

Answer 1

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

• for example bone.

Question 2

What are the advantages of using X-rays ?

Answer 2

1) relatively inexpensive

2) very quick to obtain

Question 3

What are the disadvantages of using X-rays ?

Answer 3

1( transmission of radiation to the patient

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

Question 4

What are the initial imaging choice for skeletal trauma ?

Answer 4

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

Question 5

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

Answer 5

• osteomyelitis
• chronic arthritis (rheumatoid , osteoarthritis)

-

Question 6

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

Answer 6

Articular cartilage - it appears as a joint space

Question 7

Define a fracture

Answer 7

A complete or incomplete break in the continuity of the bone

Question 8

What are the 8 types of fractures ?

Answer 8

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

Question 9

Describe the nature of a transverse fracture

Answer 9

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

Question 10

Describe the nature of a linear bone fracture

Answer 10

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

Question 11

Describe the nature of an oblique non-displaced fracture

Answer 11

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

Question 12

Describe the nature of an oblique displaced fracture

Answer 12

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

Question 13

Describe the nature of a spiral fracture

Answer 13

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.

Question 14

Describe nature of compression fracture

Answer 14

• 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

Question 15

Describe the nature of green stick fractures

Answer 15

• 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.

Question 16

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

Answer 16

Epiphyseal separation fractures

Question 17

Describe the nature of epiphyseal separation fractures

Answer 17

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

Question 18

Describe the nature of a communited fracture

Answer 18

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

Question 19

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

Answer 19

Epiphyseal separation fractures

Question 20

Describe the nature of slipped upper femoral epiphysis

Answer 20

• 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.

Question 21

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

Answer 21

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

Question 22

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

Answer 22

Centre in the diaphysis of long bones.

Question 23

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

Answer 23

Epiphysis

Question 24

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

Answer 24

Growth hormone

Question 25

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

Answer 25

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

Question 26

What are the short bones in the wrist called ?

Answer 26

Carpal bones

Question 27

What are the short bones in the ankles called ?

Answer 27

Tarsal bones

Question 28

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

Answer 28

Carpal bones in the wrist

Question 29

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

Answer 29

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

Question 30

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

Answer 30

- early /delayed puberty - growth hormone deficiency - hypo/hyperthyroidism - malnutrition

Question 31

What are the 3 phases of fracture repair ?

Answer 31

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

Question 32

What occurs during the inflammatory phase of fracture healing ?

Answer 32

- haematoma forms - tissue death - inflammation by granulocytes - callus has NOT yet formed

Question 33

How long does the inflammatory phase last ?

Answer 33

- hours to days

Question 34

What occurs during the reparative phase ?

Answer 34

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

Question 35

How long does the reparative phase lasts?

Answer 35

Days to weeks

Question 36

What occurs during the remodelling phase ?

Answer 36

Replacement of hard callus with mature bone

Question 37

How long does the remodelling phase last?

Answer 37

Months to years

Question 38

What does it mean by the ‘ radio graphic union ‘

Answer 38

Fracture line eventually becomes completely obscured

Question 39

What does CT stand for ?

Answer 39

Computed tomography

Question 40

What is another term for CT scans ?

Answer 40

CAT scanning ( computerised axial tomography)

Question 41

What are the advantages of CT scans ?

Answer 41

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

Question 42

What are the disadvantages of CT scanning ?

Answer 42

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

Question 43

What are most CT scans performed with ?

Answer 43

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

Question 44

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

Answer 44

Hounsfield units( HU)

Question 45

What is the density of water in HU ?

Answer 45

0 HU

Question 46

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

Answer 46

Black

Question 47

Anything denser than water will appear what colour ?

Answer 47

White or grey

Question 48

What colour would soft tissue appear ?

Answer 48

Grey

Question 49

What colour would bone appear ?

Answer 49

White

Question 50

What colour would air , Fat and water appear ?

Answer 50

Black

Question 51

What is the best method to image soft tissues ?

Answer 51

MRI scans

Question 52

What are advantages for MRI scans ?

Answer 52

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

Question 53

What are disadvantages of MRI scans ?

Answer 53

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

Question 54

How does an ultrasonography work ?

Answer 54

- 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.

Question 55

What are the advantages for ultrasonography ?

Answer 55

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

Question 56

What are the disadvantages of ultrasonography ?

Answer 56

1( highly dependant on a skilled operator for interpretation of images 2) resolution of deep tissues is poor 3) limited suitability for bone imaging

Question 57

What is nuclear medicine?

Answer 57

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

Question 58

What are disadvantages of nuclear medicine ?

Answer 58

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.