Stroke territories Flashcards

1
Q

What are the 2 main group that stroke can be divided into?

A
  1. Ischaemic
    - constitutes about 85-90% of water
  2. Haemorrhagic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are 2 overlapping areas of Ischaemic group?

A
  1. Thromboembolic
  2. Haemodynamic
    Interplay between them in stroke setting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When does Ischaemia occur?

A

When the blood flow through one or more your coronary arteries is decreased

Perfusion drops to a certain threshold

Nutrient supplied to the brain, oxygen and glucose, drops to a critical level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the consequence of nutrients dropping to a critical level?

A
  1. Decoupling of potassium-ATPase pump of the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are 2 major processes of de-coupling of potassium-ATPase pump?

A
  1. Influx of calcium into the cells

2. Release of glutamate into the synaptic cleft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What leads to further increase in intracellular calcium and ventral cellular death?

A

Attachment of NADPH receptors which is a irreversible process
Further increase in intracellular calcium
Ventral cellular death - end result of ischaemic process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the most vulnerable to the effect of blocked artery?

A

Tissue closest to the blocked artery

Become infarcted tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What can be supported for longer by collateral circulation?

A

Surrounding tissue away from area of infarction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens to the tissue if blood supply is reversed?

A

Will recover
If occlusion persists - get infarcted tissue
The lower the perfusion areas, less time is needed before infarction occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are 2 parameters that infarct are dependent on?

A
  1. Severity of blood supply

2. Duration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the most used modality in acute setting?

A

CT

Looking for signs of acute stroke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is CT scan used to look for?

A

To exclude haemorrhage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What looks at major blood vessels?

A
  1. CTA

2. Angiogram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is intraluminal thombus in a vessel?

A

Looking for dense MCA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens when you lose perfusion?

A

Lose grey matter interface

Anterior circulation is lost in that area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the posterior circulation constituted by?

A

Vertebral-basilar circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is anterior circulation constituted by?

A

Anterior middle cerebral arteries arising from termination of internal carotid arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where does midline anastomosis occur?

A

between anterior circulation and anterior communicating arteries

There is further anastomosis communication of the anterior and posterior by the posterior communicating arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the 3 major arterial territories?

A
  1. Middle cerebral artery (MCA) -largest
  2. Anterior cerebral artery (ACA) - paramedially
  3. Posterior cerebral artery (PCA) - posteriorally
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What has invariable supply from anterior circulation by recurring arteries of hebru?

A

Caudate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is supplied by MCA?

A

Some of the lenticulate striate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is difficult in their supply?

A

Middle deep grey structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is basilar arteries involved in?

A

Brainstem and cerebellar hemisphere

24
Q

What is CT fogging?

A

Equalisation of the cellular fluid shifts as they shift back to more conventional depositions
(Day 3-5)

25
Q

What is a finding on an enhanced CT scan?

A

Look for thrombus within vessel that is blocked

26
Q

What is MCA dot sign?

A

early marker of thromboembolic occlusion of the distal MCA branches seen in the sylvian fissure

Principally affected area of the brain is the Insula

27
Q

what does MCA supply?

A

Deeper ganglionic structures

  • Thalami
  • Caudate
  • Lenticulostriates structures
28
Q

Example of PCA infarct

A
  1. Paramedian-dorsally

2. Also extending along the inferior temporal lobe

29
Q

Example of Basilar arteries

A

Involves the:

  1. Brainstem
  2. Cerebellar hemispheres
30
Q

What involves all of the territories ?

A

Central cause of ischaemia/Infarction
Loss of grey/white matter interface both hemispheres
Cant appreciate the deeper ganglionic structures
Paroxysmal prominence of the tentorium

31
Q

Why is CT perfusion used?

A

To scrutinize what is happening at the physiological level

Take sequential volumetric imaging through a slab of tissue - level of roughly MCA

Formation of 2 curves - arterial curve and venous curve

Derive from that parametric graphs:

  • MTT
  • CBF
  • CBV
32
Q

Relative increase in cerebral blood flow

A

Pertains to pneumbral tissue rather than infarcted tissue

33
Q

What is CBV useful for ?

A

Triaging patients where there is uncertainty about the extent of infarcted tissue

34
Q

Paucity of vessels

A

A borderzone between anterior and middle cerebral arteries

There is also an area of low density vessels from MCA - deep water shed zone

  1. cortical - between anterior and middle cerebral arteries
  2. Deeper areas - cortical and proximal M1 segments of MCA
35
Q

What is watershed zones infarcts?

A

Occur at the border between cerebral vascular territories where the tissue is furthest from arterial supply and thus more vulnerable to reductions in perfusion

36
Q

What does the sub-cortical areas incorporate?

A

Deeper ganglia as you work your way through top to bottom of the brain

37
Q

What does MRI help with

A

Help patients that present with stroke

38
Q

DWI

A

Looking for an increase in signal

39
Q

ADC map

A

Looking for a decrease in signal

40
Q

what are TIA?

A

Mini strokes

41
Q

What happens following a TIA?

A

The likelihood of having a formal stroke is highest in the first few days then 7 days then 14 days after

42
Q

How can you further classify patients presenting with TIA?

A
ABCD2 score
A- Age > 65 
B - BP > 140/95
C - Paresis - Speech/Visual
D - symptom pathology > 1 hour 
Also if you are diabetic
43
Q

A score of 4 on the ABCD2 scale?

A

risk is smaller in the next 7 days of developping the stroke

44
Q

A score of 5 on the ABCD2 scale?

A

Risk drops quite remarkably to 12%

45
Q

What is a common cause of stroke?

A

Atherosclerosis

46
Q

What are the 3 classifiers of stroke?

A
  1. NASCET
  2. ECST
  3. CC
47
Q

What are the 2 complicastions of Carotid dissection?

A
  1. Thromboembolic

2. Haemodynamic - narrow lumen and reduce the blood flow

48
Q

What is the treatment for Carotid dissection?

A
  1. Medical
49
Q

Initial stage of patient presenting with ischaemic stroke

A
  1. Clinical examination and rapid radiological assessment
  2. Imaging in the form of CT is required
  3. Medical –> Thrombolysis [within time scale]
50
Q

What are 2 major studies of ischaemic stroke?

A
  1. NINDS trial - within 3 hours of onset

2. ECLAS3 - within 3-4.5 hours off onset

51
Q

Endovascular Stroke Management

A
  1. Proximal vessel occlusion
52
Q

What are the 3 major studies published ?

A
  1. MR CLEAN
  2. EXTEND-IA
  3. ESCAPE
    shows efficacy in selected patients in the vascular treatment for stroke
53
Q

MR CLEAN

A

most of the control group were in the proximal or ICA/MCA

between intervention and control group there is a shift of MRES group of better outcome

54
Q

What strategies can be used for endovascular stroke

A
  1. Chemical

2. Mechanical - stent

55
Q

What are the 2 classifications of Intracranial Haemorrhage?

A
  1. Intraxial

2. Extra-axial

56
Q

What are examples of Extra-axial Haemorrhage?

A
  1. Sub-dural
  2. Extra-dural/epidural
  3. Subarachnoid
57
Q

What is an example of surgical emergency?

A

Epidural

lots of mass effect