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
What is a finding on an enhanced CT scan?
Look for thrombus within vessel that is blocked
26
What is MCA dot sign?
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
what does MCA supply?
Deeper ganglionic structures - Thalami - Caudate - Lenticulostriates structures
28
Example of PCA infarct
1. Paramedian-dorsally | 2. Also extending along the inferior temporal lobe
29
Example of Basilar arteries
Involves the: 1. Brainstem 2. Cerebellar hemispheres
30
What involves all of the territories ?
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
Why is CT perfusion used?
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
Relative increase in cerebral blood flow
Pertains to pneumbral tissue rather than infarcted tissue
33
What is CBV useful for ?
Triaging patients where there is uncertainty about the extent of infarcted tissue
34
Paucity of vessels
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
What is watershed zones infarcts?
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
What does the sub-cortical areas incorporate?
Deeper ganglia as you work your way through top to bottom of the brain
37
What does MRI help with
Help patients that present with stroke
38
DWI
Looking for an increase in signal
39
ADC map
Looking for a decrease in signal
40
what are TIA?
Mini strokes
41
What happens following a TIA?
The likelihood of having a formal stroke is highest in the first few days then 7 days then 14 days after
42
How can you further classify patients presenting with TIA?
``` ABCD2 score A- Age > 65 B - BP > 140/95 C - Paresis - Speech/Visual D - symptom pathology > 1 hour Also if you are diabetic ```
43
A score of 4 on the ABCD2 scale?
risk is smaller in the next 7 days of developping the stroke
44
A score of 5 on the ABCD2 scale?
Risk drops quite remarkably to 12%
45
What is a common cause of stroke?
Atherosclerosis
46
What are the 3 classifiers of stroke?
1. NASCET 2. ECST 3. CC
47
What are the 2 complicastions of Carotid dissection?
1. Thromboembolic | 2. Haemodynamic - narrow lumen and reduce the blood flow
48
What is the treatment for Carotid dissection?
1. Medical
49
Initial stage of patient presenting with ischaemic stroke
1. Clinical examination and rapid radiological assessment 2. Imaging in the form of CT is required 3. Medical --> Thrombolysis [within time scale]
50
What are 2 major studies of ischaemic stroke?
1. NINDS trial - within 3 hours of onset | 2. ECLAS3 - within 3-4.5 hours off onset
51
Endovascular Stroke Management
1. Proximal vessel occlusion
52
What are the 3 major studies published ?
1. MR CLEAN 2. EXTEND-IA 3. ESCAPE shows efficacy in selected patients in the vascular treatment for stroke
53
MR CLEAN
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
What strategies can be used for endovascular stroke
1. Chemical | 2. Mechanical - stent
55
What are the 2 classifications of Intracranial Haemorrhage?
1. Intraxial | 2. Extra-axial
56
What are examples of Extra-axial Haemorrhage?
1. Sub-dural 2. Extra-dural/epidural 3. Subarachnoid
57
What is an example of surgical emergency?
Epidural | lots of mass effect