24 - Imaging of CNS

Question 1

Are plain films (EG X ray) used very often to image the CNS?

Answer 1

Largely supplanted by CT

Question 2

Catheter angiography

Answer 2

Inject catheter into an artery (normally femoral now), inject contrast into desired vessel (EG circle of Willis).
Image, EG X ray, CT

Question 3

Only situation in which ultrasound is used to image CNS

Answer 3

Neonates (in adults, skull blocks ultrasound waves)

Question 4

Imaging technique which can resolve blood travelling to different parts of the brain without additional contrast

Answer 4

fMRI

Question 5

Tactography

Answer 5

Able to image white matter tracts.
Water movement is restricted by axons.
This divides brain into voxels.
Can find the dominant direction in which water moves.

Question 6

Nuclear medicine

Answer 6

Single positron emission computer tomography (SPECT)

Positron emission tomography (PET)

Question 7

Issue with CT imaging of cortex

Answer 7

Very similar density of grey and white matter.

Need a narrow window to differentiate them.

Question 8

Appearance of grey and white matter in a T1-weighted MRI

Answer 8

Grey matter is grey, white matter is white

Question 9

What are T2-weighted MRIs good at imaging?

Answer 9

Pathology.
Water-sensitive, so can detect abnormal water content due to abnormal metabolism (EG Inflammation), abnormal cells (tumours, cortical dysplasias).

Question 10

What are basal ganglia composed of?

Answer 10

Grey matter, separated by white matter tracts

Question 11

Lentiform nucleus

Answer 11

Globus pallidus and putamen

Question 12

Basal ganglia

Answer 12

Globus pallidus, putamen, caudate

Question 13

Components of limbic system
1
2
3
4

Answer 13

Hippocampus
Amygdala
Anterior thalamic nuclei
Fornix

Question 14

Type of myelination of cranial nerves

Answer 14

Schwann cells

Question 15

Is CT or MRI better at imaging bone?

Answer 15

CT

Question 16

Small danger with angiograms

Answer 16

Can rarely cause stroke