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Flashcards in Imaging Deck (75)
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1
Q

what is the role of imaging in arthritis

A

make a diagnosis

monitor disease activity and response to treatment

2
Q

what are the sero-negative arthrides

A

psoriatic arthritis, ankylosing spondylitis,

reiters syndrome

3
Q

what is reiters syndrome

A

reactive arthritis

4
Q

what is the disease distribution of OA

A

asymmetrical
affects weight bearing/ active joints
affects other joints where overuse, previous injury, previous arthritis

5
Q

describe the radiographic features of OA

A

(Loss) asymmetrical cartilage wear which lead to asymmetric joint space reduction

(osteophytes) periosteal stimulation leads to marginal osteophyte formation
(sclerosis) increased subchondral bone cellularity and vascularity excites bone turnover leading to sclerosis of subchondral bone

(subchondral cysts) synovial fluid dissects into bone forming cysts

weakened bone caves in, resulting in joint deformity

6
Q

what is the distribution of RA

A
usually symmetrical 
any synovial joint but:
-MCP, MTP
-PIP (not DIP)
-wrists, hips, knees, shoulders 
-atlantoaxial joint (C1/2)- ligamentous instability and subluxation

sacroiliac joint and spine involvement

7
Q

describe the radiographic features of RA

A

synovial proliferation and reactive joint effusion cause soft tissue swelling

hyperaemia (increased blood supply) causes bone demineralisation resulting in periarticular osteoporosis

inflammatory pannus destroys bone, initially at joint margins (as no hyaline cartilage to protect bone at margins) and then later throughout the joint

capsular and ligamentous softening allow joint subluxation and deformity

exposed eroded bone ends may fuse (ankylosis) (much more common in sero negative arthritis)

ill-defined periarticular bone formation (fuzzy)

8
Q

what is the process of ankylosis

A

inflammation followed by ossification leading to fusion of the vertebrae

9
Q

what distribution of is the psoriatic arthritis

A

small joints of hands and feet

DIP, MCP, PIP joints, IP joint great toe

10
Q

what is the distribution of ankylosing spondylitis

A

scattered lower limb large joints

spine and sacroiliac joints

11
Q

what is the distribution of reiters syndrome

A

scattered lower limb large joints

lower limb entheses (achilles and plantar fascia onto the calcaneous)

12
Q

what are signs of early rheumatoid arthritis disease

A

increased joint vascularity
inflammed synovium
bone marrow oedema
subtle bone erosion

13
Q

what can an isotrope bone scan show in arthritis

A

increased vascularity around joints accompanies synovitis and is shown on an isotope bone scan

14
Q

what might ultrasound show in arthritis

A

thickening of synovium and increased blood flow within it can be demonstrated by colour doppler ultrasound

15
Q

what can show bone marrow oedema

A

MRI

16
Q

what does bone marrow oedema usually precede

A

significant joint erosion/ damage

17
Q

what might an MRI showing radiocarpal erosions trigger

A

treatment to prevent worsening of disease

18
Q

what does an x ray show

A

bone outlines

19
Q

what does a CT show

A

bone outlines in more detail and some soft tissue structures (e.g. lumbar discs)

20
Q

what do MRIs show

A

bone outlines in less detail but shows bone marrow, discs, ligaments and the spinal cord and nerves (all soft tissue structures)

21
Q

what are the normal curves of the spine

A

cervical lordosis, thoracic kyphosis, lumbar lordosis

22
Q

what are the shared components of the 3-7th cervical, 12 thoracic and 5 lumbar vertebrae

A
vertebral body
posterior arch:
-2 pedicles
-2 laminae
- 1 spinous process 
-2 transverse processes
23
Q

what does the neutral foramen of the vertebrae lie inferior to

A

the pedicle

24
Q

what do the articular processes do

A

project superiorly and inferiorly between the pedicles and laminae, forming the facet joints

25
Q

are consecutive vertebrae the same size

A

yes

26
Q

why is C1 different from the other vertebrae

A

have no vertebral body

anterior and posterior arches united by two large lateral masses which articulate with the occipital bone and C2

27
Q

why is C2 different from the other vertebrae

A

has an ondontoid process which projects superiorly into C1 forming a joint with its anterior arch

28
Q

when is a CT used to image spinal trauma

A

X ray shows # but more detail required, any more fractures present?

x ray normal but high clinical suspicion of #

29
Q

what is responsible for spinal stability

A

intervertebral ligaments

30
Q

what implies that intervertebral ligaments are intact on a CT or x ray

A

normal alignment of the vertebrae

31
Q

what are the intervertebral ligaments

A
anterior and posterior longitudinal ligaments 
ligamentum flavum (runs between spinous processes)
32
Q

what imaging shows ligaments directly

A

MRI

33
Q

what do normal and damaged ligaments look like on MRI

A

normal ligaments black

damaged ligaments light

34
Q

when is MRI used in spinal trauma

A

to provide detail of the spinal ligaments

in patients with neurological deficit which is not explained by x ray or CT, to show soft tissue abnormality

35
Q

what might be seen in a bony tumour of the spine on x ray and CT

A

bone destruction (reduced bone density)

vertebral collapse (pathlogical #)

bone sclerosis (osteoblasts stimulated)

36
Q

what are the unique MRI findings of a bony tumour of the spine

A

early- bone marrow infiltration

late- extradural mass and spinal chord compression

37
Q

can you see inter-vertebral disc on x ray

A

no

38
Q

what imaging shows discs and discs prolapse

A

CT and MRI (MRI best, shows early disc dehydration which precedes herniation)

39
Q

what imaging shows the spinal chord

A

MRI (CT shows it poorly)

40
Q

what are the 4 causes of spinal cord disease

A

trauma, demyelination, tumour, ischaemia

41
Q

what imaging can appreciate normal vertebral anatomy

A

x rays

42
Q

what imaging is the best for soft tissue disorders (disc prolapse, malignant cord compression and spinal cord disease)

A

MRI

43
Q

how can you see the ondontoid peg via x ray

A

view from open mouth

44
Q

how can the scaphoid bone be shown

A

via different views e.g. oblique planes

45
Q

how might a fracture appear on a bone

A

lucency crossing a bone, cortical extension, spiral/ transverse, comminution, joint involvement, angulation, displacement, impaction, avulsion

46
Q

what is an avulsion fracture

A

injury to bone where a tendon/ligament attaches- tendon/ ligament come off

47
Q

how can you tell an avulsion fracture fragment of bone

A

has incomplete corticated contour

48
Q

what can mimic an avulsion fracture fragment

A

sesamoid bones, accessory ossification centres, old united fractures

49
Q

how do you check humero capitella allignment

A

should hit the medial of the capitella

50
Q

what direction does the humeral head displace in an anterior shoulder dislocation

A

inferiorly and medially

51
Q

when is the fat pad of the distal humerus abnormal

A

when it is posterior not anterior to the distal humerus

52
Q

what is a buckle fracture or bowing

A

when immature bones are damaged but bend or bow unlike mature bones that snap and break

53
Q

what is the weakest part of developing bone

A

physis (the lucency between the epiphysis and metaphysis) (physis can mimic fractures_

54
Q

what is a salter harris fracture

A

fracture of the epiphysis or growth plate of a bone

55
Q

why does a fractures in the radius/ ulnar usually mean an injury in the ulnar/ radius aswell

A

as they form a ring

56
Q

can you see plastic or wood on x ray

A

no same density as soft tissue

57
Q

what is seen on a colles fracture

A

dorsal angulation

58
Q

supracondylar fractures are easily missed, what must you assess

A

humerocapitellar alignment, posterior fat pad, damage to brachial artery

59
Q

what is the risk of a scaphoid fracture

A

AVN due to retrograde blood supply, lack of healing, early onset OA

60
Q

what is a bennetts fracture

A

first metacarpal base, tendons pulling thumb distal cause displacement

61
Q

what other imaging modality can overcome x rays problem with overlapping structures

A

CT- is cross sectional

62
Q

what other imaging modality can overcome x rays inability to show some structures

A

CT- can show fractures irregardless on plane

63
Q

what other imaging modality can overcome x rays difficulty to show undisplaced fractures

A

MRI- can show undisplaced fractures

64
Q

what other imaging modality can overcome x rays inability to show soft tissue injury

A

ultrasound- superficial soft tissue

MRI- deep soft tissue

65
Q

what do lower limb fractures often look like

A

impacted so look sclerotic

66
Q

what complications can an intracapsular fracture (infront of trochanteric line) cause

A

interfere with blood supply to the femoral head, AVN

treated with haemarthroplasty

67
Q

what are you at risk of with a femoral shaft fracture

A

blood loos and fat embolus

68
Q

what is lipohaemarthrosis

A

blood and fat collecting int he suprapatellar recess- sign of intra articular fracture

69
Q

what artery can be imposed in knee dislocation

A

popliteal

70
Q

what movement causes a tibial plateau fracture

A

valgus force with foot planted

71
Q

what imaging is good for assessing extensor mechanisms injuries

A

US

72
Q

what injuries is MRI good at showing

A

meniscal tears, cruciate ligament tears, hyaline cartilage injuries, subtle fractures

73
Q

what movements often cause ankle injuries

A

inversion or eversion

74
Q

what is a lis franc injury

A

TMT joint injury- where one or more metatarsals are displaced from the tarsus

75
Q

how do you asses TMT joint conjurity

A

1st and 2nd AP view

3rd to 5th oblique view

Decks in MSK Class (71):