Imaging

Question 1

what is the role of imaging in arthritis

Answer 1

make a diagnosis

monitor disease activity and response to treatment

Question 2

what are the sero-negative arthrides

Answer 2

psoriatic arthritis, ankylosing spondylitis,

reiters syndrome

Question 3

what is reiters syndrome

Answer 3

reactive arthritis

Question 4

what is the disease distribution of OA

Answer 4

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

Question 5

describe the radiographic features of OA

Answer 5

(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

Question 6

what is the distribution of RA

Answer 6

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

Question 7

describe the radiographic features of RA

Answer 7

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)

Question 8

what is the process of ankylosis

Answer 8

inflammation followed by ossification leading to fusion of the vertebrae

Question 9

what distribution of is the psoriatic arthritis

Answer 9

small joints of hands and feet

DIP, MCP, PIP joints, IP joint great toe

Question 10

what is the distribution of ankylosing spondylitis

Answer 10

scattered lower limb large joints

spine and sacroiliac joints

Question 11

what is the distribution of reiters syndrome

Answer 11

scattered lower limb large joints

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

Question 12

what are signs of early rheumatoid arthritis disease

Answer 12

increased joint vascularity
inflammed synovium
bone marrow oedema
subtle bone erosion

Question 13

what can an isotrope bone scan show in arthritis

Answer 13

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

Question 14

what might ultrasound show in arthritis

Answer 14

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

Question 15

what can show bone marrow oedema

Answer 15

MRI

Question 16

what does bone marrow oedema usually precede

Answer 16

significant joint erosion/ damage

Question 17

what might an MRI showing radiocarpal erosions trigger

Answer 17

treatment to prevent worsening of disease

Question 18

what does an x ray show

Answer 18

bone outlines

Question 19

what does a CT show

Answer 19

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

Question 20

what do MRIs show

Answer 20

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

Question 21

what are the normal curves of the spine

Answer 21

cervical lordosis, thoracic kyphosis, lumbar lordosis

Question 22

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

Answer 22

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

Question 23

what does the neutral foramen of the vertebrae lie inferior to

Answer 23

the pedicle

Question 24

what do the articular processes do

Answer 24

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

Question 25

are consecutive vertebrae the same size

Answer 25

yes

Question 26

why is C1 different from the other vertebrae

Answer 26

have no vertebral body | anterior and posterior arches united by two large lateral masses which articulate with the occipital bone and C2

Question 27

why is C2 different from the other vertebrae

Answer 27

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

Question 28

when is a CT used to image spinal trauma

Answer 28

X ray shows # but more detail required, any more fractures present? x ray normal but high clinical suspicion of #

Question 29

what is responsible for spinal stability

Answer 29

intervertebral ligaments

Question 30

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

Answer 30

normal alignment of the vertebrae

Question 31

what are the intervertebral ligaments

Answer 31

``` anterior and posterior longitudinal ligaments ligamentum flavum (runs between spinous processes) ```

Question 32

what imaging shows ligaments directly

Answer 32

MRI

Question 33

what do normal and damaged ligaments look like on MRI

Answer 33

normal ligaments black | damaged ligaments light

Question 34

when is MRI used in spinal trauma

Answer 34

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

Question 35

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

Answer 35

bone destruction (reduced bone density) vertebral collapse (pathlogical #) bone sclerosis (osteoblasts stimulated)

Question 36

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

Answer 36

early- bone marrow infiltration late- extradural mass and spinal chord compression

Question 37

can you see inter-vertebral disc on x ray

Answer 37

no

Question 38

what imaging shows discs and discs prolapse

Answer 38

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

Question 39

what imaging shows the spinal chord

Answer 39

MRI (CT shows it poorly)

Question 40

what are the 4 causes of spinal cord disease

Answer 40

trauma, demyelination, tumour, ischaemia

Question 41

what imaging can appreciate normal vertebral anatomy

Answer 41

x rays

Question 42

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

Answer 42

MRI

Question 43

how can you see the ondontoid peg via x ray

Answer 43

view from open mouth

Question 44

how can the scaphoid bone be shown

Answer 44

via different views e.g. oblique planes

Question 45

how might a fracture appear on a bone

Answer 45

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

Question 46

what is an avulsion fracture

Answer 46

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

Question 47

how can you tell an avulsion fracture fragment of bone

Answer 47

has incomplete corticated contour

Question 48

what can mimic an avulsion fracture fragment

Answer 48

sesamoid bones, accessory ossification centres, old united fractures

Question 49

how do you check humero capitella allignment

Answer 49

should hit the medial of the capitella

Question 50

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

Answer 50

inferiorly and medially

Question 51

when is the fat pad of the distal humerus abnormal

Answer 51

when it is posterior not anterior to the distal humerus

Question 52

what is a buckle fracture or bowing

Answer 52

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

Question 53

what is the weakest part of developing bone

Answer 53

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

Question 54

what is a salter harris fracture

Answer 54

fracture of the epiphysis or growth plate of a bone

Question 55

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

Answer 55

as they form a ring

Question 56

can you see plastic or wood on x ray

Answer 56

no same density as soft tissue

Question 57

what is seen on a colles fracture

Answer 57

dorsal angulation

Question 58

supracondylar fractures are easily missed, what must you assess

Answer 58

humerocapitellar alignment, posterior fat pad, damage to brachial artery

Question 59

what is the risk of a scaphoid fracture

Answer 59

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

Question 60

what is a bennetts fracture

Answer 60

first metacarpal base, tendons pulling thumb distal cause displacement

Question 61

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

Answer 61

CT- is cross sectional

Question 62

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

Answer 62

CT- can show fractures irregardless on plane

Question 63

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

Answer 63

MRI- can show undisplaced fractures

Question 64

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

Answer 64

ultrasound- superficial soft tissue | MRI- deep soft tissue

Question 65

what do lower limb fractures often look like

Answer 65

impacted so look sclerotic

Question 66

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

Answer 66

interfere with blood supply to the femoral head, AVN treated with haemarthroplasty

Question 67

what are you at risk of with a femoral shaft fracture

Answer 67

blood loos and fat embolus

Question 68

what is lipohaemarthrosis

Answer 68

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

Question 69

what artery can be imposed in knee dislocation

Answer 69

popliteal

Question 70

what movement causes a tibial plateau fracture

Answer 70

valgus force with foot planted

Question 71

what imaging is good for assessing extensor mechanisms injuries

Answer 71

US

Question 72

what injuries is MRI good at showing

Answer 72

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

Question 73

what movements often cause ankle injuries

Answer 73

inversion or eversion

Question 74

what is a lis franc injury

Answer 74

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

Question 75

how do you asses TMT joint conjurity

Answer 75

1st and 2nd AP view | 3rd to 5th oblique view