Medical Imaging: Joints Flashcards
What is lipohaemoarthrosis?
What is it indicative of?
Fat and blood in a joint
Indicative of an intra-articular fracture
What does this xray indicate?
Lipohaemoarthrosis:
- Effusion beneath patella - straight line above femur
- ‘FBI’ sign: fat-blood interface sign
Fracture to tibial head
What causes lipohaemarthrosis?
Fatty marrow separates from the blood (water based) which gives the characteristic fat-fluid level indicated by the straight line on the xray.
What types of imaging can be used when a higher sensitivity is needed to image a joint?
What can they identify?
CT and MRI
Can identify haematocrit effect:
- Fat
- Synovial fluid
- Blood
Name 3 common joint emergencies seen on imaging
Lipohaemarthrosis
C-spine injury
Joint dislocation
What indications may there be for spinal imaging?
Trauma
Malignancy
Infection: TB, discitis, abscess
Disc prolapses
Degenerative changes
Limb pain (neuropathic)
What imaging modalities may be used for a suspected c-spine injury?
X-ray
CT
What is the first line imaging used for suspected cauda equina syndrome?
MRI
What imaging modality should be used for suspected discitis?
MRI
In what circumstances may nuclear imaging of the spine be indicated?
Malignancy
Describe the method of interpreting a C-spine x-ray
Adequecy (all cervical vertebrae visible? and ideally top of T1)
Alignment: are the lines smooth? Are there any bony prominences outside of the lines?
- Anterior vertebral line
- Posterior vertebral line
- Spino-laminar line
- Posterior spinous line
Bones: are the borders of the cortex of each bone smooth?
Cartilage: are the spaces between the vertebrae uniform?
When imaging joints, why would a CT scan be used over x-ray?
What can CT scan not exclude in terms of joints?
Higher sensitivity
In trauma situations where x-ray appears normal
If x-ray shows an abnormality, to further investigate
Cannot exclude ligamentous injury
What are the benefits of using MRI?
What type of tissue can they show?
Higher sensitivity
Can see ligaments, nerves and soft tissue
Can look closely at individual nerves: demyelination
No radiation compared to CT and MRI
WHat type of imaging can be used to investigate suspected demyelination?
MRI
What does this MRI show?
Prolapse of lumbar vertebral disc causing spinal cord compression
What does the MRI show?
Discitis causing obliteration of the disc and damage to the vertebral bodies above and below.