Module 2

Question 1

What is a MRI?

Answer 1

Magnetic resonance imaging, allows us to look at the brain while it is alive

Question 2

What is a Structural MRI?

Answer 2

Images of gross anatomy. DIfferent varieties of scan by changing timing of magnetic signalling which can highlight certain tissues or blood vessels. Takes 5 minutes to acquire one 3D image.

Question 3

What are limitations of the Structural MRI?

Answer 3

Does not measure tissue type. Measurement in mm. Does not always distinguish bone from air well. Contrast between tissue types can be poor

Question 4

What are complementary techniques for Structural MRI?

Answer 4

Computed Topography: (CT/CAT) X-ray but more detailed + safe for those with metal implants

Histology

Question 5

What is a Diffusion MRI?

Answer 5

Based on movement of water. Restricted more in some directions, gives most info about axon directions. Indirectly gives info about both the direction and integrity of axons.

Question 6

What are differences between the Structural and Diffusion MRI?

Answer 6

Structural MRI takes 5 minutes to acquire single image, but has higher resolution.

Diffusion MRI takes lots of fast images (1-3 secs) because each image is sensitive to different diffusion direction but resolution is low to help with blurring.

Question 7

Diffusion MRI’s do not measure…?

Answer 7

Axon size, Single fibres (difficult to deal with crossing fibres), Difficult to measure pulsatile regions e.g. brainstem.

Question 8

What are complementary techniques for the Diffusion MRI?

Answer 8

Tracer studies: Done post mortem, track individual fibres, directions of connections and have very fine spatial resolution.

Histology

Question 9

What is a Functional MRI?

Answer 9

Allows us to observe changes in brain waves as someone performs a basic task (limited to what can be done in MRI machine), lower resolution and many fast images in five minutes

Question 10

What are complementary techniques for Functional MRI?

Answer 10

PET scan and EEG