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I'd like to show an example of an IDH mutant

0:06

grade two astrocytoma.

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So this example is a patient who presented with seizures

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and as you can see there is an abnormal area

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of signal intensity on the flare imaging

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that is predominantly in the medial left temporal lobe

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and starts to affect some of the sub insular region

0:28

and external capsule.

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On the flare imaging, we see

0:31

that it is relatively well-defined.

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Unfortunately this case has an imaging finding

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that is likely to lead to this being unresectable tumor

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and that is, you see it on either side of the M1 segment

0:48

of the left middle cerebral artery, which is seen

0:51

as the flow void in black here

0:54

and it goes out to the middle cerebral artery bifurcation.

0:59

So gonna be hard to remove this from the the MCA

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and they will not even try.

1:05

This is a case that's probably going

1:06

to be treated predominantly with radiation therapy

1:09

and temozolomide if it is MG mt

1:13

promoter positive.

1:15

So bright end signal intensity on the flare image

1:19

on the T two wade scan.

1:21

You see it as well as being very bright.

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One of the features that may suggest an IDH mutant tumor

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is if there is a flare T two mismatch

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where the lesion is very bright on the T two weighted scan,

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but has internal central areas typically

1:41

of darker signal on the flare.

1:43

It turns out that that's a pretty good indicator

1:46

of IDH mutant status and

1:48

therefore an astrocytoma as opposed to

1:53

IDH wild type glioblastoma.

1:57

If we look at the diffusion weighted scan on this patient,

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we see that it does not have bright signal on the DWI

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and on the A DC map, the vast majority of this is bright,

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not dark, maybe a small area here of

2:12

decreased a DC.

2:14

We would follow that, make sure that that small area doesn't

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expand into a larger area of restricted diffusion

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because that might indicate, um,

2:24

de-differentiation going from grade two to a higher grade.

2:28

If we look at the perfusion maps on the patient,

2:33

it does not have hyperperfusion associated with it.

2:38

This is our relative cerebral blood volume

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corrected map on this image.

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How do we know what's hyper perfused

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versus hypoperfused?

2:52

Well, again, I would say go to the ventricles.

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Here's the frontal horn of the lateral ventricle,

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and in this case

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The dark black is the CSF, which we know has no perfusion.

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So dark black would be hypoperfusion

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or you can look out at the periphery at the gray matter.

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And we see that the gray matter is red.

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So red gray matter is more perfused than the purple

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and blue, which is the white matter.

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And in this case, the tumor is not red.

3:24

It's more closely as, uh, approximated to the white matter

3:28

and to the CSF of the lateral ventricle.

3:33

And therefore this is a hypoperfused tumor.

3:36

So this is an IDH mutant grade two

3:41

astrocytoma, which has a

3:45

flare mismatch sign that is,

3:47

there are areas in the flare which are darkened signal,

3:50

whereas on the T two weighted image, bright

3:53

and signal intensity reduction in a DC,

3:57

low perfusion going along with a lower grade

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IDH mutant astrocytoma.

4:05

I hope this case is illustrative to you and we'll move on.