0:01

I did wanna show the variance that one

0:04

can observe in patients with PRES.

0:07

Here is our typical feature where we have high

0:10

signal intensity extending in the white matter of

0:13

the parietal lobe, but this patient also showed focal

0:16

areas of hemorrhage within the PRES abnormality.

0:21

That was seen on the susceptibility-weighted

0:23

scan. Hemorrhage, less than 10%, does occur.

0:27

However, here we have the same patient,

0:30

another area of hemorrhage in an area

0:32

of posterior reversible encephalopathy

0:35

syndrome, usually a non-hemorrhagic process.

0:37

Here's a patient who has PRES that is

0:39

predominantly frontal lobe, so not posterior, but—

0:43

ARAS, anterior reversible encephalopathy

0:46

syndrome. And in this individual, there

0:48

was a focal area of contrast enhancement.

0:51

Again, contrast enhancement, 10% or less.

0:55

Here we have a patient who has bilateral

0:57

posterior reversible encephalopathy syndrome only.

1:02

On the diffusion-weighted scan, you see that there is

1:05

indeed bright signal intensity from cytotoxic edema.

1:10

On the ADC map, this is non-reversible.

1:12

This is infarcted tissue.

1:15

So again, some of the variants that you can

1:17

see with posterior reversible encephalopathy

1:20

syndrome with respect to the reversibility—

1:23

that reversibility, when the offending agent or

1:27

the blood pressure is treated appropriately,

1:29

this will usually reverse in about two to four weeks.

1:32

Here is a patient for whom we have the MRI from the

1:35

initial insult and then a two-month follow-up.

1:38

You notice that—

1:39

it's gotten better and completely reversed.

1:42

You wouldn't even know that the

1:43

patient ever had PRES in this case.

PRES Variants

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