Principles of Imaging/Radiology

Question 1

what are the most common types of arthritis?

Answer 1

rheumatoid arthritis

osteoarthritis

Question 2

what joints are usually affected in OA?

Answer 2

weight bearing joints as due to wear and tear (spine, hip, knee, thumb base)
often asymmetrical

Question 3

what are the radiological features of OA?

Answer 3

asymmetrical loss of joint space
subchondral sclerosis
subchondral cysts
osteophyte formation
gross joint deformity

Question 4

what causes subchondral sclerosis in OA?

Answer 4

increased subchondral bone cellularity and vascularity excited bone turnover

Question 5

what causes osteophytes formation?

Answer 5

periosteal formation

Question 6

describe joint involvement in RA?

Answer 6

only affects synovial joints
symmetrical
commonly
- MCP, MTP
- PIP
- wrists, hips, knees, shoulders
- C1/C2
DIP sparing

Question 7

what happens in the synovium in RA?

Answer 7

increased proliferation and vascularisation in synovium

Question 8

what are the radiographic features of RA?

Answer 8

soft tissue swelling 
periarticular osteoporosis (darkening of bone on X ray due to loss of bone density)
destruction of joint margin by inflammatory pannus (later throughout the joint)

Question 9

what causes soft tissue swelling in RA?

Answer 9

synovial proliferation and reactive joint effusion

Question 10

what causes osteoporosis in RA?

Answer 10

hyperaemia causes bone demineralisation

Question 11

how can deformity occur in RA?

Answer 11

capsular and ligamentous softening allow joint subluxation and deformity

Question 12

what can happen to eroded bone in RA?

Answer 12

eroded bone ends may fuse (ankylosis)

Question 13

what are the common characteristics of sero-negative arthritis?

Answer 13

sacro-iliac joint and spine involvement
ill defined periarticular bone formation
tendency to joint ankylosis

Question 14

describe new bone formation in RA vs OA?

Answer 14

RA = more fuzzy and ill defined

Question 15

why are fractures more unstable in RA?

Answer 15

bc all bones and ligaments etc are ossified so no soft tissue to stabilise the fracture

Question 16

name 3 types of sero-negative arthritis?

Answer 16

psoriatic arhtitis
ankylosing spondylitis
reiter’s syndrome (reactive arthritis)

Question 17

what are the shared features of each sero-negative arthritis?

Answer 17

sacroiliac joint and spine involvement
ill defined periarticular bone formation
tendency to joint ankylosis

Question 18

what do radiographic features indicate in arthritis?

Answer 18

indicate that bone and joint damage that has already occurred, therefore patients might have missed the opportunity to have their disease modified

Question 19

what early features of arthritis can be shown by other imaging tests and may indicate that its not too late to modify the disease?

Answer 19

increased joint vascularity
inflamed synovium 
bone marrow oedema
subtle early bone erosion
- e.g bone scan, doppler US, MRI, MR

Question 20

what can be seen on imaging of the spine?

Answer 20

bones
ligaments
IV discs
Spinal cord and nerves
blood vessels

Question 21

what is the most detailed imaging?

Answer 21

X ray = bone outline
CT = detailed bone outline and some soft tissues
MRI = bone outline, bone marrow, discs, ligaments, spinal cord and nerves (all soft tissue)

Question 22

describe normal curvature of the spine

Answer 22

smooth

loss of normal alignment spells trouble

Question 23

what are the common features of all vertebrae from C3-L5?

Answer 23

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

Question 24

where is the neural foramen in vertebrae?

Answer 24

lies inferior to the pedicle

Question 25

what forms the facet joints?

Answer 25

articular processes project superiorly and inferiorly between the pedicles and laminae forming the facet joints with adjacent vertebrae

Question 26

how can adjacent vertebrae indicate a problem?

Answer 26

consecutive vertebrae usually have similar size | variation can indicate problem

Question 27

describe C1

Answer 27

no vertebral body | anterior and posterior arch united by two large lateral masses

Question 28

describe C2

Answer 28

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

Question 29

what is the best imaging to use for spinal fracture?

Answer 29

CT

Question 30

when is a CT used in spinal trauma?

Answer 30

if X ray shows fracture but more detail needed | if X ray normal but high clinical suspicion of fracture

Question 31

what provides stability to the spinal column?

Answer 31

surrounding ligaments

Question 32

how can you image spinal ligaments?

Answer 32

only MRI | but seeing normal alignment of the vertebrae on X ray or CT implies intact ligaments and a stable spine and vice versa

Question 33

what do normal/damaged ligaments look like on MRI?

Answer 33

normal = black damaged = light gap in black line shows where tear is in the ligament

Question 34

when is MRI used in spinal trauma?

Answer 34

to get detail of spinal ligaments | in patients with neurological deficit which is not explained by X ray or CT

Question 35

what soft tissue injuries can cause a neurological deficit?

Answer 35

acute prolapsed IV disc epidural haematoma spinal cord damage

Question 36

what does a bony tumour look like on X ray and CT?

Answer 36

bone destruction vertebral collapse bone sclerosis

Question 37

what does a bony tumour look like on MRI?

Answer 37

``` early = bone marrow infiltration late = extradural mass and spinal cord compression ```

Question 38

what do bone metastases look like on MRI?

Answer 38

dark spots within the bone

Question 39

how are IV discs imaged?

Answer 39

discs are invisible on X rays (may show some disc space narrowing but correlates poorly with sciatica symptoms) CT and MRI can show discs but MRI is best as it shows earlier disc dehydration

Question 40

how is the spinal cord imaged?

Answer 40

invisible on X ray and only poorly shown by CT | only adequately shown by MRI

Question 41

what can cause spinal cord disease?

Answer 41

trauma demyelination tumour ischaemia

Question 42

describe the disease distribution in psoriatic arthritis

Answer 42

small joints of hands and feet DIP joints IP joint of big toe

Question 43

describe the disease distribution of ankylosing spondylitis

Answer 43

scattered lower limb large joints

Question 44

describe the disease distribution of reiters syndrome

Answer 44

scattered lower limb large joints | lower limb entheses