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This is another example of tumefactive

0:03

demyelinating lesion.

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In this case,

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two lesions that one can see are in the

0:10

periventricular location on the right and left side

0:14

seen on the FLAIR scans.

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And we note also on the ADC map that there does appear

0:20

to be a focus of an area of lower signal intensity

0:25

representing cytotoxic edema.

0:27

So, that's another identifier for some of the

0:31

tumefactive demyelinating lesions that there

0:33

may be a peripheral rim of low ADC.

0:37

How do we know that this is not metastatic disease?

0:43

Well, let's look at the postgadolinium enhanced images.

0:47

We see once again a very strange appearance

0:52

to the enhancement pattern.

0:55

We have an open arc of enhancement.

0:58

It's almost semicircular enhancement,

1:00

as well as a central area of contrast enhancement.

1:05

This would be very unusual for a neoplasm.

1:09

On the other hand,

1:11

this lesion on the left-hand side

1:14

could represent the metastasis.

1:19

So, let's next look at the perfusion imaging.

1:25

Perfusion imaging, although it's not in color,

1:28

shows absence of high signal intensity to suggest

1:34

perfusion increase.

1:37

And this was indeed yet another tumefactive

1:41

demyelinating lesion confirmed on surgery.

1:45

Normally,

1:45

we would not want to perform surgery to find this out,

1:48

but by virtue of the fact that this

1:50

was a bilateral multiple lesions.

1:54

It was unusual for TDL,

1:56

and the patient did go for biopsy.