0:00

This is another examination of a patient

0:02

who had known multiple sclerosis

0:05

and was being evaluated for the effectiveness

0:08

of therapy.

0:09

As I stated earlier,

0:11

I'd like to have up initially the axial

0:13

FLAIR, the axial T2-weighted scan,

0:16

and the diffusion-weighted scan.

0:17

In this case, on the right hand side,

0:19

you're seeing the ADC map that allows us

0:23

to look for areas of cytotoxic edema without

0:27

having the issue of T2 shine through.

0:31

So we can see right from the bat

0:32

that this patient has a large

0:34

volume of demyelination.

0:36

As we scroll through the posterior fossa,

0:40

initially, we're going to let our eyes stray

0:43

to the T2-weighted scan

0:44

as the most accurate for identifying

0:47

demyelinating plaque.

0:49

As I said, though,

0:50

demyelinating plaques are better

0:51

seen on the T2-weighted scan.

0:53

And it's also because of the prevalence of

0:56

CSF ghosting artifact that

0:59

you see on FLAIR imaging.

1:01

FLAIR is particularly susceptible to CSF

1:04

pulsation artifact, and therefore,

1:06

what we're seeing going through the brain

1:08

stem on the left hand side

1:10

is actually CSF ghosting artifact

1:12

rather than demyelination.

1:14

It's not seen on the T2-weighted scan.

1:17

Yet another argument for using the

1:19

T2-weighted scan in the posterior fossa.

1:22

Now, if we look at the T2-weighted scan

1:24

at this juncture,

1:26

we are identifying a central area within

1:29

the pons of demyelination,

1:31

which is quite hard to see here

1:33

on the FLAIR imaging.

1:36

Let's continue to scroll further superiorly.

1:39

Again, we're seeing some areas in the central

1:42

pons on the T2-weighted scan

1:44

that I would call areas of demyelination

1:47

in this patient,

1:48

but not really reliably seen on the FLAIR imaging.

1:52

I think I've made my point.

1:55

As we scroll further superiorly,

1:59

we come to the supratentorial region.

2:01

Now, we're going to focus a little bit more

2:03

on the FLAIR imaging going back and forth,

2:06

and we see that there is a large volume of

2:10

demyelination in the periventricular regions,

2:13

as well as in subcortical regions.

2:17

I generally am not that critical with

2:21

regard to whether something is subcortical

2:24

or juxtacortical or deep in the white matter.

2:27

So, for example,

2:29

here on the FLAIR scan, we have the pia,

2:33

the sulcus,

2:34

and in this example,

2:36

I would call this a juxtacortical

2:39

demyelinating plaque.

2:42

I would call that one as well juxtacortical.

2:45

I would call this one juxtacortical.

2:47

Some people,

2:48

when they're looking at the centrum semiovale

2:53

in lesions that are not

2:55

adjacent to the gray matter,

2:58

will use the term deep white matter lesions

3:01

rather than using it juxtacortical.

3:03

Why is this...

3:04

Why do I bring this up?

3:05

Why is this important?

3:07

Well, the McDonald criteria specify that the

3:11

four locations are juxtacortical

3:13

or subcortical,

3:14

periventricular,

3:16

infratentorial and spinal cord lesions.

3:20

So, if you just had lesions like this

3:23

that are in the deep white matter

3:25

without being close to the gray matter,

3:28

would you include them and say that it

3:30

does indeed fulfill the criteria

3:32

of two or more locations,

3:34

i.e., juxtaportical and periventricular or not?

3:39

So, depending upon what a stickler

3:42

you are for the nomenclature,

3:43

you may count these as juxtacortical or not.

3:49

Again, as we look at these lesions,

3:52

we're going to be looking both at the ADC map

3:56

to see whether there is any area

3:59

of cytotoxic edema,

4:02

as well as the post-gadolinium-enhanced scans.

4:07

Now, just looking at these white matter lesions,

4:11

can I predict which ones are going to

4:14

show contrast enhancement or not?

4:17

That's not something that is easily

4:19

done on T2 or FLAIR scans.

4:22

Sometimes, you think,

4:24

"Ah. This one seems a little different

4:26

than the other one,"

4:27

so it might show contrast enhancement and

4:30

and be an active plaque.

4:31

That is very hard to predict.

4:33

And hence, we have to do the

4:34

post gadolinium enhanced scans,

4:36

certainly for the initial evaluation of the patient.

4:39

However,

4:40

the fulfillment of the criteria

4:44

of being spaced out in time,

4:48

that is a polyphasic disorder,

4:50

a disorder in which there are different aged lesions.

4:55

One can fulfill that criteria by having a

5:00

prior study and showing new lesions on

5:03

FLAIR scan that were not present

5:05

on the prior study.

5:06

So the two ways we say that the patient

5:09

has demyelinating plaques of different ages

5:13

is by showing whether the plaques are

5:16

enhancing or not,

5:17

and whether or not

5:19

they preexisted on a prior study.

5:22

So, let's eliminate the drama

5:24

and let's see what looks...

5:26

how the patient looks on the

5:28

postgadolinium enhanced scan.

5:30

Well, I'll scroll them together

5:33

and we'll try to fix that in a moment.

5:35

So here, we have a patient who has

5:37

multiple enhancing plaques,

5:40

some of which are showing more

5:42

of an open arc appearance,

5:44

some of which are showing a complete

5:46

rim of enhancement,

5:48

some of which are showing

5:49

solid enhancement,

5:50

and I would even say some of which show

5:53

more of a linear pattern of enhancement.

5:56

At this juncture,

5:57

we can see that there are some plaques

6:00

that are enhancing.

6:02

And let's just stop here.

6:06

These are fairly analogous sections.

6:13

Here we have

6:15

the hand knob area,

6:17

and what we're seeing is a plaque here

6:21

that does not enhance versus

6:24

multiple other enhancing plaques.

6:27

So once again,

6:28

here we have a non-enhancing plaque.

6:31

Here we have a non-enhancing plaque,

6:34

here we have non-enhancing plaques.

6:37

So these, we would say,

6:38

no active blood-brain barrier breakdown.

6:42

And therefore, we would assume that these

6:43

are more chronic,

6:44

as opposed to those that

6:46

are showing contrast enhancement,

6:48

which are demonstrated also

6:50

on the FLAIR scan.

6:51

So, spaced out in both location

6:56

as well as in age,

7:00

defining it as multiple sclerosis

7:03

by McDonald criteria.

7:05

I'd like to pull down the coronal scan

7:08

just to remind you of the value of

7:12

scrolling through the orbits to ensure

7:15

whether or not the patient has

7:17

active optic neuritis.

7:19

This is an example of a patient whose

7:21

optic nerves do not show contrast enhancement.

7:24

So, please utilize all the pulse sequences

7:29

because to demonstrate the optic nerve

7:32

demyelination on the axial FLAIR or

7:34

T2-weighted scan is quite hard.

7:36

I'm pulling down the sagittal.

7:39

Again,

7:40

the sagittal FLAIR scan, very useful.

7:42

It shows us that the patient has

7:44

atrophy of the corpus callosum.

7:46

And this is a little bit more ragged

7:49

in the colossal septal interface.

7:51

So, let me demonstrate that.

7:53

As opposed to the previous case where I

7:55

showed a fine linear area of bright signal

7:59

intensity at the colossal septal interface,

8:01

this has a more ragged area,

8:03

identifying the demyelination

8:07

at the colossal septal interface.

8:10

And that, again,

8:11

is characteristic of multiple sclerosis as

8:14

opposed to other demyelinating disorders.

8:19

And you also get a better sense of just

8:21

how dramatic the demyelination

8:23

is on the sagittal

8:26

FLAIR scans.

8:28

If one were to make a coronal

8:32

reconstruction from the sagittal scan,

8:36

you may be able to identify demyelination

8:39

in the optic nerves.

8:43

That would be another option.

8:45

So, yet another example of a patient who has

8:49

pretty robust active multiple sclerosis

8:52

with both enhancing and non-enhancing plaques,

8:55

in this case,

8:56

none of which showed cytotoxic edema on

8:59

the diffusion-weighted scan,

9:01

but multiple ones showing contrast

9:03

enhancement in the brain.

9:06

On the sagittal FLAIR scan,

9:08

you might also get a chance to look at the

9:10

cervical spine, if that has not been

9:12

separately scanned.

9:13

In this case,

9:14

there's nothing dramatic seen in the

9:16

cervical spine in this patient.