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I'd like to review the major intracranial

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arterial territories because you need to understand these

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in order to identify strokes on MRI.

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So, the largest area, the lateral frontal lobes,

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temporal lobe, insula,

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frontal and parietal lobes more superiorly

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are the middle cerebral artery territory.

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Anteriorly,

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you see the medial frontal lobes,

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the caudate heads,

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the anterior medial parietal lobes in green,

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and those are the anterior cerebral artery territory.

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More inferiorly,

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you see the mesial temporal lobes,

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mesial parietal and occipital lobes,

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and that's the posterior cerebral artery territory.

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And the thalami are also posterior

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cerebral artery territory.

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They arise from the thalamic perforators

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that come off the posterior PComs

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and the P1 segments of the posterior cerebral arteries,

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and then the pons is also supplied

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by the posterior circulation.

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It's supplied by pontine perforators,

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and those come off the basilar artery.

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And then, we'll talk about the basal ganglia.

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So, the basal ganglia are mostly supplied

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by the lenticulostriate arteries

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that come off the MCA M1 segment,

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and to a lesser extent,

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the ACA A1 segment.

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And then, the anterior choroidal artery is here in green.

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Notice mesial temporal lobe

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and posterior limb of the internal capsule.

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I just showed you that

1:27

that comes off the ICA,

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just above the posterior communicating artery.

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So, that's anterior choroidal artery.

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Let's talk about the cerebellar artery in blue.

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You see the posterior inferior cerebellar artery,

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that's supplied by the PICA,

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comes off the vertebral artery

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or can come off as a PICA, ICA vessel

1:46

of the basilar artery.

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And then, the anterior inferior cerebellar artery

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territory is outlined in brown here,

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and that typically comes off the basilar artery.

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And then, the superior cerebellar arteries

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are seen here in pink.

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They typically come off the superior aspect

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of the basilar artery.

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So, those are the major intracranial

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vascular territories.

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And I'm just going to show you a couple of

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cases on diffusion weighted imaging.

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So, this is a big left MCA stroke.

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These patients typically present with a

2:15

contralateral hemiplegia, hemianesthesia,

2:18

and gaze preference to the lesion side.

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If it's on the left side,

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most people map their language there,

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so they'll have a global aphasia,

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and the superior division is Broca's aphasia.

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Inferior frontal lobe,

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you know what you want to say but can't say it.

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And Wernicke's is the superior temporal lobe.

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And basically,

2:36

you speak in a bunch of gibberish.

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And then, here's a patient who has

2:41

an ACA territory infarct.

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Remember the medial frontal

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and medial anterior parietal lobe, and they have,

2:47

remember your leg bumps there on the homunculus,

2:49

so you tend to have leg weakness

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and disinhibition is another

2:53

big syndrome associated with

2:56

right-sided ACA strokes.

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And then, this is the medial temporal lobe and

3:01

posterior limb of the internal capsule.

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People confuse this with the poster

3:05

cerebral artery territory,

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but this is the anterior choroidal artery territory.

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And usually, they have contralateral weakness,

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and it may get the optic tracts.

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You can have visual symptoms as well.

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This is a PICA territory infarction,

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inferior cerebellum.

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The medulla can also be infarcted with this syndrome.

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Typically, the patients have ataxia,

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vertigo, nystagmus, nausea, and vomiting.

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And again, they can have a lateral

3:30

medullary syndrome if the medulla is involved,

3:32

where you have loss of pain and temperature on

3:33

the ipsilateral side and contralateral body.

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This is a superior cerebellar infarct.

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It's a little more chronic,

3:39

so it's bright on the ADC maps.

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And these patients also have ataxia, nystagmus,

3:45

nausea, vomiting.

3:45

They can also have a Horner syndrome.

3:47

And lastly, this is a basilar tip embolus.

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So remember,

3:51

the pontine perforators supply the pons.

3:53

So that's involved.

3:54

And then, it involved both PCA territories,

3:57

medial temporal and occipital lobes.

3:59

And when the patients have infarcted brain stem

4:01

like this, it's characterized by somnolence,

4:04

cranial nerve palsies, and weakness.

4:07

And then, this is a patient who just has

4:10

more distal right PCA embolus,

4:12

involving the mesial temporal and occipital lobes,

4:15

and they have a homonymous hemianopsia.

4:18

If there's midbrain involvement,

4:20

they'll also have hemiplegia,

4:21

ataxia, and a third nerve palsy.