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Now, I'm going to show you a case of a patient

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who had malignant collaterals.

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These are images of an 80-year-old female

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who had acute left hemiparesis.

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She was status post thoracic surgery with

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new onset of atrial fibrillation.

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These are imaged at approximately 2 hours.

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And on our non-contrast CT,

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we can see the hyperdense vessel sign

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in the right MCA,

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and

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we can already see some early loss of grey-white

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differentiation in the right temporal lobe,

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the right basal ganglia,

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right frontal lobe, right parietal.

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If you look, compared to the contralateral side,

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you can see that nice hyperdense cortex.

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I don't see that.

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There are areas where you just can't see that

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on the right side.

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So, it already looks like a pretty big infarct.

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But it was very early,

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and I don't think it was initially

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recognized how much loss of grey-white differentiation

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there was on the original CT.

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And the patient had other favorable

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clinical factors.

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So, they eventually took her to thrombolysis.

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But in any case,

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let me show you the rest of this case.

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So, that's the non-contrast CT.

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We're going to get our CTA.

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We're going to look at the intracranial MIPS.

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We knew there was going to be an MCA stem clot

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because we just saw the hyperdense vessel sign

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and because of the symptoms,

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and you can see that there's cut off.

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There are malignant collaterals.

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I really see hardly any collaterals.

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You can see nice left MCA looks normal.

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The bilateral PCAs look normal.

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And we'll take a look at the raw data.

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So, let's look at the raw data.

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So, we're going to look at...

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the arch has a little bit of calcification in it,

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not too much.

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We're just going to follow this right carotid up,

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and we get to the bifurcation,

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and there's some mild disease,

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relatively mild,

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maybe mild to moderate stenosis.

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Not that exciting.

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So, we're thinking it's probably

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not the atheromatous disease.

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It probably is the AFib that caused her stroke.

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We'll follow that vessel up.

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And again, some mild stenosis

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in the carotid siphon, and there's the cutoff.

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And we're going to look at the collaterals.

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And again,

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you see hardly any collaterals going up

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over the convexity.

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And then again, the CTA source images.

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So now, it's a little bit easier to see this

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extent of area where there's poor perfusion,

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loss of grey-white differentiation throughout

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the right MCA territory.

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But you do see good vessels on the left side,

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so compare it with the left side.

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So, non-contrast CT looked like the infarct

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is going to be pretty big.

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CTA source images increase

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the conspicuity of the infarct.

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Again, that may tend to overestimate

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the size of the infarct,

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but it increases the conspicuity of ischemia.

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So, this patient went to thrombolysis.

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Here is the DWI,

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and this shows pretty big infarct

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involving the insula,

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the right anterior and posterior temporal lobes,

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inferior frontal lobe, inferior parietal lobe,

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right basal ganglia,

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and then frontal and parietal cortex.

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So, even though she came in really early,

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got thrombolysed early,

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it was near complete opening of the vessels,

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still had a big infarct because

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she had malignant collaterals,

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and the infarct grew very quickly.

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And also,

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I just want to show you the FLAIR images.

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In early infarcts,

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patients usually don't have

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much FLAIR hyperintensity.

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But in these cases where they

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have malignant collaterals,

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they have early breakdown of

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the blood brain barrier,

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and sometimes they have FLAIR hyperintensity

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pretty early on.

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So in any case,

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that's our case of malignant collaterals.