MRI

Question 1

How does an MRI scan work?

Answer 1

The patient is placed in a strong magnetic field and is subjected to s pulse of radio waves which deflects hydrogen ions in the body. The radio waves are removed at the hydrogen ions deflect to their original position, releasing radio waves. These waves can be detected by a computer to produce an image

Question 2

What tissues appear dark on a T1 weighted scan?

Answer 2

Bone
Air
Water
Calcified elements

Question 3

What tissues appear bright on a T2 weighted scan?

Answer 3

Tissues with high water content

Extracellularly located methemoglobin

Question 4

What are the advantages of MRI?

Answer 4

No ionising radiation
No need for contrast agents
High resolution image

Question 5

What are the disadvantages of MRI?

Answer 5

Can’t be used for patients with cochlear implants, cardiac pacemakers, shrapnel etc.
Expensive
Time consuming
Claustrophobic and scary

Question 6

What is a functional MRI?

Answer 6

This measures changes in signal in the brain due to changing neural activity.