Neuroimaging

Question 1

What is the principle behind CT scans?

Answer 1

Uses X-rays to image structures based on densities–tissue, fluid, air, etc.

Question 2

Features of epidural hemorrhage?

Answer 2

Lens-shaped–bleed that occurs between periosteum and bone and does not cross sutures.

Arterial bleed (i.e. meningeal) with RAPID clinical course.

Associated with skull fractures/post-traumatic injury.

Question 3

Features of subdural hemorrhage?

Answer 3

Crescent-shaped bleed that follows dura and stopped by falx at midline.

Slower growing but can get big.

Mostly post-traumatic.

Question 4

Features of subarachnoid hemorrhage?

Answer 4

In sulci, following contours of the brain.

Subarachnoid space is CONTINUOUS with ventricles.

Aneurysm rupture (“worst headache ever”), but can also be post-traumatic. Aneurysms commonly at branch points, such as A-comms and P-comms.

Question 5

Features of intraparenchymal hemorrhage?

Answer 5

Commonly due to hypertension that causes central bleeds–predisposing conditions can be underlying mass, infarct conversion, amyloid angiopathies, etc.

Trauma can result in hemorrhage in all compartments.

Question 6

What are the few pathologies that can cross corpus callosum?

Answer 6

High grade glioma (“butterfly” pattern on MRI)

MS (really really bad MS)

Lymphoma, especially due to AIDS

Question 7

What are some general symptoms with strokes to each of the following?

Right MCA
Left MCA
ACA
PCA

Answer 7

Right MCA (insula, BG)- left motor and sensory (not legs)
Left MCA (insula, BG, speech regions) - speech, right motor and sensory (not legs)
ACA (medial frontal) - motor and sensory for legs
PCA (medial occipital) - vision