neurovascular

Question 1

Spetzler-Martin grading system

Answer 1

AVM grading system, correlates with operative outcome

Size of nidus
6cm = 3

Eloquence of adjacent brain
non-eloquent = 0
eloquent = 1

Venous drainage
Superficial only = 0
deep = 1

Eloquent regions:
sensorimotor, language, visual cortex, hypothalamus, thalamus, brainstem, cerebellar nuclei or regions directly adjacent to these structures

non-eloquent regions:
frontal and temporal lobe, cerebellar hemispheres

Question 2

What is moyamoya disease and what are the imaging (CTA/MRA and angiography) findings

Answer 2

idiopathic, non inflammatory, non atherosclerotic progressive vasculo-occlusive disease involving the circle of willis.

typically involves supraclinoid ICA, but PCA involved in 50% of patients.

typically bilateral distal ICAs/circle of willis. The vessels can be of decreased caliber with occlusion.

• Collateral circulation will usually form, with flow voids on MRI.
• Ivy sign on FLAIR (pial collaterals causing high signal in sulci)
• Multiple foci of microbleeds
• Prominent deep medullary veins.
• transdural branches extending from middle meningeal artery

On angiography, small abnormal net-like vessels proliferate giving a “puff of smoke” appearance. Not always seen on CTA/MRA.

Question 3

What is differential diagnosis of intracranial mycotic aneurysms?

Answer 3

Tumor emboli from atrial myxoma

Question 4

What are possible complications of subarachnoid hemorrhage

Answer 4

Hemorrhage induced hydrocephalus

Secondary infarction due to vasospasm

Leptomeningeal superficial siderosis: iron deposition in meninges secondary to chronic recurrent SAH.
CN 1, 2 and 8 most commonly affected

Question 5

Name the four types of intracranial vascular malformations

Answer 5

AVM
Capillary telangiectasia
Cavernous malformation
Venous malformation

Question 6

True or false:

AVMs typically displace the adjacent brain parenchyma

Answer 6

False

AVM replaces but does not displace brain tissue unless complicated by hemorrhage and edema.

Question 7

What are the 2 causes of edema surrounding an AVM?

Answer 7

Recent hemorrhage

Venous thrombosis with infarction

Question 8

What is a vein of galen varix?

Answer 8

• Primary parenchymal AVM drains into vein of Galen, which secondarily enlarges.
• Thalamic AVM with nidus is usually the primary AVM.
• Uncommon in neonates
• Higher risk of hemorrhage than the vein of
Galen AVM

Question 9

What is the artery of percheron?

What is its origin?

Answer 9

Rare variant of the posterior cerebral circulation characterised by a solitary arterial trunk that supplies blood to the paramedian thalami and rostral midbrain bilaterally.

This artery branches from one of the proximal segments of the PCA (as opposed to 2 arteries arising from the bilateral PCAs in normal anatomy).

Question 10

Which territory is affected in an artery of percheron infarct?

Answer 10

Bilateral thalamic and mesencephalic infarctions

Question 11

While coursing along the clivus, in which canal does CN6 pass?

Answer 11

Dorello’s canal