0:01

This is an example of a 41-year-old male patient

0:04

presenting with headaches and seizures,

0:07

and has a relatively well-defined

0:10

T2 hyperintense lesion

0:12

in the right frontal operculum.

0:15

As you can see,

0:16

it does not show any contrast enhancement.

0:18

And here's the tumor seen

0:20

on the sagittal weighted images,

0:21

sagittal post-contrast images.

0:23

You can see the tumor is in the frontal,

0:27

infralateral frontal lobe,

0:28

in the precentral region and frontal operculum .

0:32

And this tumor is not showing you dark signal on

0:36

the FLAIR images in the central part of the tumor,

0:39

as we expect for a T2 FLAIR mismatch sign to be.

0:42

In fact, it's bright,

0:44

homogeneously bright on the FLAIR images.

0:47

And that is the reason I would not call

0:49

this a T2 FLAIR mismatch sign.

0:51

But that does not mean that this cannot

0:54

be an IDH mutated astrocytoma.

0:56

If I see the sign, that's 100% positive predictive

0:59

value to call this an IDH mutated astrocytoma.

1:03

If I don't see the sign,

1:05

this could be an IDH mutated astrocytoma,

1:08

or it could be an oligodendroglioma,

1:10

or even it could be an IDH wild-type tumor.

1:12

But because it's a younger patient

1:15

and presenting with this very superficial mass,

1:19

this in fact turned out to be

1:22

an IDH mutated astrocytoma.

1:24

But I would not call this T2 FLAIR mismatch sign

1:26

based on the imaging alone.