Imaging - Key Points Flashcards
What do x-rays show?
Bones
What do CT scans show?
Bones in more detail
Some soft tissue structures e.g. lumbar discs
What do MRI scans show?
Bones in less detail Bone marrow Discs Ligaments Spinal cord and nerves (i.e. all soft tissue structures)
What imaging modalities show bones?
X-rays
CT
MRI
What imaging modalities show soft tissues?
CT
MRI (especially)
Where does the neural foramen lie on the vertebrae?
Inferior to the pedicle
Name of the joint that forms between the articular processes of 2 adjacent vertebrae?
Facet joints
How does C1 vary from the other vertebrae?
No vertebral body
How does C2 differ from the other vertebrae?
Has an odontoid process (projects superiorly into C1 forming a joint with its anterior arch)
When is CT used to image spinal trauma?
X-ray show fracture -> more details required, ? any more fractures present
X-ray normal but high clinical suspicion of fracture
What does abnormal vertebral alignment on x-ray or CT imply?
Ligament damage and an unstable spine
Why type of imaging can be used to directly see intervertebral ligaments?
MRI
Colour of normal and abnormal ligaments on MRI?
Normal = black Abnormal = light
When is MRI used to image spinal trauma?
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 e.g. acute prolapsed IV disc, epidural haematoma, spinal cord damage
What unique features about bony tumours of the spine can MRI tell you (in comparison to x-ray and CT)?
Bone marrow infiltration
Extradural mass
Spinal cord compression
What mode of imaging is best for viewing the IV discs?
MRI (CT can also be used but not as good)
What is the only imaging modality which adequately shows the spinal cord?
MRI
What are the 4 main (broad) causes of spinal cord disease?
Trauma
Demyelination
Tumour
Ishcaemia
Are x-rays useful in patients with sciatica?
No
What are the 2 main roles of imaging in arthritis?
Making diagnosis
Monitoring disease activity and response to treatment
Is OA joint involvement normally symmetrical?
No
What leads to sclerosis of subchondral bone in OA?
Increased subchondral bone cellularity and vascularity excites bone turnover leading to sclerosis
Wha causes joint deformity in OA?
Weakened bone caves in
Is RA normally symmetrical?
Yes
What spinal levels can RA affect?
C1/ C2
What causes soft tissue swelling in RA?
Synovial proliferation and reactive joint effusion
What causes periarticular osteoporosis in RA?
Hyperaemia causing bone demineralisation
What detroys bone at the joint margins in RA?
Inflammatory pannus
What leads to subluxation and deformity in RA?
Capsular and ligamentous softening
What can cause ankylosis (bone fusion) in RA?
Exposed eroded bone ends
What seronegative arthritis tends to affect the small joints of the hands and feet as well as DIP hints, IP joint of great toe?
Psoriatic arthritis
What seronegative arthritis tends to cause scattered lower limb large joint arthritis and lower limb entheses?
Reiters Syndrome
What type of scan cause show increased vascularity around joints which accompanies synovitis?
Isotope bone scan (allows RA to be diagnosed before joint damage occurs)
What scan can be used to show thickening of synovium and increased blood flow within it?
Colour Doppler Ultrasound