0:00

So, these are images of a 67-year-old

0:04

male who had left arm weakness.

0:06

And this is the non-contrast CT,

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and what we can see here is some hyperdensity

0:13

and an M2 branch of the right MCA.

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And then, there's some subtle

0:18

hypoattenuation in the right insula,

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and a little loss of gray-white differentiation

0:24

in the posterior frontal lobe.

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We look at the thicker sections,

0:29

posterior, frontal, anterior parietal lobe,

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you can see that a little bit better.

0:32

So, some tissue probably infarcted already,

0:37

not that much.

0:39

And then, we'll take a look at the CTA.

0:44

So here's a CTA,

0:46

and we're going to follow up the

0:49

right common carotid artery,

0:51

and not much going on the neck.

0:54

It looks pretty normal.

0:56

Going up into the right,

0:58

internal carotid artery intracranially

1:01

looks pretty good.

1:03

And trace that out,

1:06

and there's a cutoff,

1:09

an M2 cutoff right here.

1:11

You can see there's non opacification

1:13

of some vessels there.

1:14

And when we look at the CTA source images,

1:18

again, we see a little subtle hypodensity

1:20

in the right insula, again,

1:23

maybe a little bit of cortex.

1:25

And we can take a look at the MIPs.

1:29

The cutoff is right here,

1:31

the M2 branch, there's some overlapping veins here,

1:34

and there's some very good collateralization.

1:39

So, we also got CT perfusion images on this case.

1:43

So we're going to look at our CT perfusion,

1:46

and we know there's some

1:48

ischemic tissue because it was hypodense

1:51

on non-contrast CT.

1:52

But when they thresholded it for less than 30%,

1:55

they didn't find anything

1:56

on the CBF and CTP images.

2:00

The Tmax greater than six was seven CCs,

2:03

so there's a mismatch

2:06

but it's tiny because there's

2:07

so little tissue involved.

2:08

And if you think about it,

2:10

this area looked hypodense from

2:12

the non-contrast CT.

2:13

So, it's really pretty matched between

2:15

the core and the penumbra.

2:18

And then, we're just going to look.

2:20

Again, this is what happens if you threshold

2:22

at 4 seconds and it becomes

2:24

a little bit larger.

2:25

That's not too surprising.

2:27

And the CBF,

2:28

just even if they used a 38% threshold,

2:32

they got several spurious lesions

2:35

on the contralateral side.

2:36

So basically, it was zero or 30%,

2:42

and the penumbra was 7 cc.

2:45

So, really small areas here.

2:48

Good arterial input function,

2:50

good venous output function.

2:52

Motion detection,

2:54

that looks good in all three axes.

2:57

And here are the actual maps.

2:59

And so, here's the CBF.

3:02

And basically, it's pretty hard to see any asymmetry.

3:07

We do see that one small area on the Tmax.

3:11

And this is, again, is just showing the placement

3:14

of the arterial input function and the venous

3:17

output function.

3:18

So this is really, again,

3:23

a matched case because you've got that

3:25

hypodensity on non-contrast CT

3:27

and a small Tmax abnormality.

3:30

And this patient did not get thrombolysed.

3:34

And here's the infarct on DWI.

3:36

It pretty much matches what we saw

3:38

on the CT of the insula

3:40

and a little bit of posterior frontal,

3:42

anterior parietal, or basically,

3:43

it's mostly anterior parietal cortex.

3:47

So, that's an example of CTP

3:50

that doesn't show much tissue at risk.