6- When to use MRI and CT

Question 1

What is a CT scan?

Answer 1

Computed tomography
radiographic tube & receiver spin around the patient during imaging producing multiple individual x-rays in multiple orientations

Question 2

What is a MRI scan?

Answer 2

Magnetic resonance imaging

Protons (H+ nuclei) induced to resonate in a strong magnetic field by radio waves

Generates proton density information

Question 3

What is enhanced in a T2 MRI image?

Answer 3

Fat and water

Question 4

What is enhanced in a T1 MRI image

Answer 4

Fat

Question 5

Name 2 problems with MRI

Answer 5

Expensive
Very susceptible to movement
Relatively poor bone detail
Metallic artefacts
Implanted medical devices may be destoryed
Takes a while to gain images

Question 6

Why would you use CT over MRI?

Answer 6

CT - better for looking at bone details
MRI - better for soft tissue detail

Question 7

What contrast media would you use for a positive contrast in a MRI?

Answer 7

Gadolinium

Question 8

what type of contrast would you use for a positive and negative contrast in CT&Radiographs?

Answer 8

+ve - radiodense material - iodine or barum

-ve contrast - radiolucent - air