Radiographs and Myelography Flashcards
Any rotation of xrays will make interpretation unreliable; especially of which two key areas?
- Disc space
- Foramen
Radiographs of spine can diagnose what? (3)
discospondylitis,
Bone neoplasia
Vertebral abnormalities such as atlanto-axial subluxation and hemivertebrae.
At the start of a dx process; if may be difficult to diagnose discospondylitis and neoplasia, why?
radiographic changes are not always visible at the onset or early stages as it depends on how advanced the pathology is.
CARE in cases of vertebral abnormalities; why?
It is essential to assess whether an abnormality is likely to be responsible for the clinical signs observed.
Why is myelography used? (2)
evaluate if there is a compressive lesion of the spinal cord
identify the exact location of the lesion.
What restraint for myelography?
GA
What xrays are taken with myelography?
Survey radiographs of the spine. Two to three subsequent radiographic projections (lateral, ventrodorsal and oblique views– when appropriate)
Where is contrast injected with myelography?
into the subarachnoid space.
Which spaces can contrast be injected with myelography? (3)
Cisterna magna
L5-L6
L6-L7
What contrast medium type for myelography?
Non ionic contrast medium
What dose is the contrast medium given for myelography?
0.2-0.3mg/kg
What happens with myelography if contrast injected too quickly?
Bradycardia
Maximum volume of contrast with myelography?
8ml
If too higher volume of contrast with myelography is given; what is there a risk of?
post myelography seizures.
CSF analysis should be performed before myelography; what condition could then deteriorate if this isnt done?
Inflammatory CNS disease
Myelography will affect CSF results for how long after?
7 days
What CSF site is appropriate for thoraclumbar lesions?
Lumbar
Which CSF site has the least complications?
Lumbar
Seizures secondary to injection of contrast are possible and more likely to be seen with which site of contrast injection?
Cisterna magna
Rare, but what is the fatal complication of cisternal myelography?
Subarachnoid haemorrhage
Can you think of any benefits of myelography over other diagnostic options? (3)
Relatively cheap
readily available test,
rapid evaluation of the entire spine and allowing dynamic studies.
Interpretation of the myelogram relies on evaluation of the contrast columns and classification into what localisation (3)
extradural,
intradural-extramedullary,
intramedullary
How do Extradural lesions present with myelography?
Deviations of the contrast column.
Examples of extradural lesions (4)
IVDD
fractures
Subluxations
Neoplasia
A golf tee sign is often seen in?
Intradural-extramedullary lesions
Examples of intradural-extramedullary lesions include (3)
arachnoid cysts,
meningiomas
nerve root tumours.
In cases where an intramedullary pathology is suspected, the myelogram may be unremarkable or may show?
divergence of the dorsal and ventral contrast column
What does divergence of the dorsal and ventral contrast column suggest?
Spinal cord swelling
Examples of intramedullary lesions include (3)
glioma
myelitis
ischaemic myelopathy.
What can be performed if interpretation of the myelographic study is difficult?
CT-myelography
