Imaging

Question 1

Describe to radiographic technique for the spinal cord (4)

Answer 1

• Take two orthogonal views
• use anaesthesia or heavy sedation
• Position well to avoid parallax
• Use appropriate exposure

Question 2

State a limitation for each of the following, radiography, myelography, CT, MRI

Answer 2

• Limited soft tissue detail
• risk of spinal nerve injury
• Lots of radiation exposure
• Very expensive

Question 3

How could you diagnose an intervertebral disc disease on radiograph? (2)

Answer 3

• Thin disc space

- Narrow spinal cord

Question 4

How does myelography work?

Answer 4

A contrast is injected into the subarachnoid space at the occipitoatlantal joint or the caudal lumbar region. It shows that CSF is flowing normally and there are no obstruction

Question 5

What three types of lesions can a myelograph show?

Answer 5

• Intramedullary
• Extramedullary/intradural
• extradural

Question 6

What does a CT scan show?

Answer 6

Slice information of the body using X-ray radiation

Question 7

What does an MRI image show?

Answer 7

Slice information of the body using hydrogen spin, shows soft tissue detail.

Question 8

What is FLAIR mode on MRI?

Answer 8

Suppresses CSF signal

Question 9

What is STIR mode on MRI?

Answer 9

Suppresses fat signals

Question 10

What contrast media is used for MRI?

Answer 10

Gadolinium

Question 11

What are the advantages of MRI? (4)

Answer 11

• Real time viewing
• No radiation
• Can cover large body areas
• Not invasive

Question 12

Describe the general principles by which an MRI image is produced (5)

Answer 12

• MRI works by applying an external magnetic field to a patient
• the protons in their body will align to create a resultant magnetic vector.
• Radiowaves are added and the protons are disturbed
• when the waves are turned off, the time taken for the protons to return to normal is recorded
• Tissues are distinguished by how long they take to realign

Question 13

How does a CT scan work?

Answer 13

A rotating X-ray tube emits radiation, taking hundreds of images and putting them together to make a 3D image.

Question 14

What are the colours of inflammation, fat, soft tissue, fast moving fluid, and static fluid, on T1 images?

Answer 14

dark, bright, grey, dark, dark

Question 15

What are the colours of inflammation, fat, soft tissue, fast moving fluid, and static fluid, on T2 images?

Answer 15

bright, bright, grey, dark, bright