Neuroradiology

Question 1

How soon after an ischaemic stroke are signs of an acute stroke visible on non contrast CT brain?

Answer 1

6 hours

Question 2

What are the signs of an acute ischaemic stroke on CTB? (3)

Answer 2

loss of grey/white differentiation (hypodense area, but not as hypodense as water)
sulcal effacement (due to swelling of cerebral parenchyma)
Linear hyperdensity (may be an affected artery thromboembolism)

Question 3

What is the most sensitive imaging test for cerebral infarction?

Answer 3

DWI (diffusion weighted imaging) MRI- diffusion restriction within infarcted tissue

Question 4

Should you do an LP in someone with sudden onset severe headache?

Answer 4

No- headache could be due to raised ICP and LP might then cause them to cone

Question 5

What does a subarachnoid haemorrhage look like on CT?

Answer 5

Hyperdense blood (white)- may be in a star pattern (suprasellar cisterns) and in sulci

May be widening of ventricles (hydrocephalus)

Question 6

What is the most sensitive test for a cerebral aneurism?

Answer 6

Cerebral CT angiogram and subsequent digital subtraction angiogram

Question 7

What are the complications of SAH? (3)

Answer 7

vasospasm–> infarction, hydrocephalus, intracerebral haemmhorage

Question 8

Wjhat is post ictal hemiparesis also known as?

Answer 8

Todd’s paresis

Question 9

What does an old infarct (>4 weeks) look like on non contrast CT?

Answer 9

Hypodense (black) with no mass effect, oedema, fresh haemmhorage

Question 10

What is the most common mechanism for ischaemic stroke?

Answer 10

Emboli from carotids/ heart

Question 11

What does an intracerebral haemorrhage look like on CT?

Answer 11

Hyperdesne lesion within the brain parechyma

Question 12

What are the 3 most common sites of intracerebral haemorrhage caused by hypertension?

Answer 12

basal ganglia, brain stem, cerebellum

Question 13

What investigations are used for MS (2 most important)?

Answer 13

LP–> CSF looking for oligoclonal bands (paraprotein from myelin breakdown)
MRI–> demyelinating plaques: multiple hyperintense lesions on T2 and FLARE (CSF supressed). Plaques often abut the ventricles.

Question 14

What t=do MS plaques look like on TI with IV contrast

Answer 14

Ring enhancement- active plaque with breakdown of BBB. No ring enhancement= old plaque or other lesion.

Question 15

Subacute onset (over a few days) of UMN weakness and signs of a unilateral upper limb accompanied by no LL signs- ddx?

Answer 15

• neoplasm (primary of mets)
• deymyelinating disease
• cerebrovascular disease (less likely given time course)

Question 16

What is vasogenic cerebral oedema?

What causes vasogenic oedema?

What is the appearance of vasogenic oedema on CT/MRI?

Answer 16

Vasogenic cerebral oedema refers to a type of cerebral oedema in which the blood brain barrier (BBB) is disrupted (c.f. cytotoxic cerebral oedema where BBB is intact). It is an extracellular oedema which mainly affects the white matter, through leakage of fluid out of capillaries.

It is most frequently seen around brain tumours (both primary and secondary) and cerebral abscesses, although some vasogenic oedema may be seen around maturing cerebral contusion and cerebral haemorrhage.

Oedema extends in a ‘finger like’ fashion into the cortex, and is hyperintense on FLAIR MRI

Question 17

What is cytotoxic cerebral oedema?

What causes cytotoxic oedema?

What is the appearance of cytotoxic oedema on CT/MRI?

Answer 17

Cytotoxic cerebral oedema refers to a type of cerebral oedema, most commonly seen in cerebral ischaemia, in which extracellular water passes into cells, resulting in their swelling- intracerebral oedema. (BBB intact)

Low diffusion on MRI DWI

Question 18

What does IV contrast enhancement of a brain lesion indicate?

What are 3 possible lesions?

Answer 18

Breakdown of BBB

Tumour, infection, demyelination.

Question 19

What are the 4 most common sources of mets to the brain?

Answer 19

lung, breast colon, melanoma

Question 20

What 2 things could hyperdensity on CT brain represent?

Answer 20

Blood or calcium

Question 21

Which kidn of brain tumour is calcification most commonly seen in?

Answer 21

meningioma