MSK Imaging Flashcards
What structuresncan the different imaging techniques show?
X-ray - bone outlines
CT - bone outlines in more detail and some soft tissue structures
MRI - bone outlines in less detail, all the soft tissue structures
What does abnormal vertebral alignment on imaging imply?
Ligament damage and unstable spine
How do normal and damaged ligaments appear on MRI?
Normal - black
Damaged - lighter
What spinal injuries can MRI show that x-ray can’t?
Soft tissue injuries, e.g.
Acute prolapsed intervertebral disc
Epidural haematoma
Spinal cord damage
What are imaging features fo vertebral tumours?
Bone sclerosis
Bone destruction
Vertebral collapse
MRI: bone marrow infiltration (early) or extradural mass and spinal cord compression (late)
What is the best imaging to show intervertebral discs?
MRI
What intervertebral disc disease can be seen on MRI?
All disc prolapses
The disc dehydration that precedes prolapse
What is the best imaging for the spinal cord?
MRI
What are the imaging features of osteoarthritis?
Asymmetric joint space reduction
Subchondral sclerosis
Osteophytes
Cysts
What are imaging features of rheumatoid arthritis?
Soft tissue swelling
Osteopenia
Erosion
Deformity
What are the imaging features of seronegative arthritides?
Enthesitis causes ill-defined bony proliferation (periarticular new bone formation)
Ossification of ligaments and bone fusion across joints
What are early imaging features of joint disease?
Increased joint vscularity
Inflamed synovial
Bone marrow oedema
Subtle bone early erosion
What are examples of when you need more than two radiograph views, and what do they need?
Cervical spine - AP, lateral and odontoid peg
Scaphoid - AP, lateral and two obliques
What are examples of variable fracture appearances?
Lucency crossing bone Cortical extension Comminution (split into 3 or 4 fractures) Joint involvement Angulation Displacement Impaction (bone denser than usual) Avulsion (fragment of bone tears away from the main mass of bone)
What is the characteristic feature of avulsion fractures on x-ray that mimics don’t have?
They are incompletely coricated
What are examples of avulsion fracture mimics?
Sesamoid bones
Accessory ossification centres
Old non-united fractures
What may be seen on x-ray if an elbow effusion is present?
Displaced fat pad
What are examples of bone injuries that only children get?
Buckle fracture (looks like a ring around the bone) Blowing Greenstick fracture (incomplete fracture)
What is the growth plate?
A lucency between the epiphysis and metaphysis in developing bones
What is different about bony ring fractures?
As it is a ring, here will always be more than one disruption to the ring
Which materials can be seen on x-ray, and which are invisible?
Metal and glass can be seen
Plastic and wood are invisible
When should you suspect pathological fracture?
Where bone abnormality seems out of proportion to the mechanism of injury
Who are colles fractures most common in?
Elderly patients with osteoporosis
Who are scaphoid fractures most common in?
Young (ish) males
