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This is a CT scan of the head

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in a two-year-old child

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with known tuberous sclerosis complex.

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We can see this coarse calcification along the

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lateral margin of the anterior body of the right

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lateral ventricle along the anterior margin of

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the atrium of the left lateral ventricle with

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several additional areas of mineralization,

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some of which are very fine,

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some of which are more coarse.

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These are calcified subependymal nodules.

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We additionally see on CT scan the multifocal

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areas of cortical dysplasia.

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Now if we compare it to MR.

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Where we see these multifocal areas

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of dysplasia. Notice on MR.

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They're hyperintense on T2-weighted imaging

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in part because of high water content.

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Well, we know water is dark on CT scan,

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so it's not surprising that these areas

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of dysplasia are hypointense on CT.

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Now some of these,

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this is a moderate to severe burden of

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dysplasia. Some of these are confluent.

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This doesn't look like just one area of

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dysplasia. It's probably several.

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We can see the overlying sulcation

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pattern is irregular.

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We have this larger area with thickened cortex.

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We can see this area here in

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the left occipital lobe

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that looks like a cystic area of dysplasia.

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That is a known finding in

1:25

tuberous sclerosis complex.

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Then post-contrast imaging shows multiple

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subependymal nodules enhancing.

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You can see this here is just a confluence of.

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Here's a nodule, here's a nodule,

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here's a nodule, here's a nodule.

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So there's multiple of them.

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The largest is along the lateral margin

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of the anterior body of the right lateral

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ventricle. And if I measure it,

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it's approximately 10 dimensions,

1:53

approximately 7 transverse dimensions

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and approximately 9 cranial-caudal dimensions.

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this is sort of on the borderline threshold for

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what's typically referred to as

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a subependymal giant astrocytoma.

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But as I've mentioned before,

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the real important designation is not the

2:16

calipers, it's the biological behavior.

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It's whether it's enlarging,

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it's whether it's impending impingement of

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the pyramid of Monroe. At the moment,

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we can imagine if this enlarges

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a little bit more,

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the Foramen of Monroe could end up being

2:32

obstructed. Now fortunately,

2:34

this is predominantly calcified.

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These areas of calcified dysplasia tend not to

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grow as fast because it's usually only the non

2:43

calcified portion that's actively growing.

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This is still a lesion in this patient

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where we want to follow it closely.

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Now, one of the things of note,

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if we look at diffusion-weighted imaging,

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we're seeing this.

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Hyperintense signal in the

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hypothalami bilaterally.

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See, here's the globus pallidus.

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We go a little bit inferior.

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It's the hypothalami.

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We're also seeing a little bit of hyperintense

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signal in the central tegmental

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tracts in the brainstem.

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What is this? Well, if you haven't seen it,

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it's hard to know,

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but it turns out that this is a very

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characteristic appearance of what's

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called myelinic edema.

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So it's edema within the myelin associated

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with vigabatrin therapy.

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Vigabatrin is an antiepileptic agent that

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is often given for a variety of clinical

3:40

presentations of seizures.

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And

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if the doses are too high for a given patient,

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you may sometimes see that abnormality.

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Now, if you see this myelinic edema,

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it's important to let the epileptologist

3:56

know this.

3:58

They may choose to reduce the dose of the agent.

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They may choose to keep it the same.

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There's no single best answer for every patient.

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They will know if that given patient,

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if reducing the dose a little bit,

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if that results in more seizures,

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it's not worth it.

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If they can reduce the dose a little bit

4:16

and not have any increase in seizures,

4:19

it may be appropriate.

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Well, in this patient, they reduced the dose,

4:24

and we can see three months later that myelinic

4:27

edema went away. So it is a reversible finding.

4:30

So this is a patient with tuberous sclerosis complex

4:34

with a moderate to severe burden

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of areas of cortical dysplasia,

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including one area of cystic dysplasia.

4:41

This patient has multiple subependymal nodules,

4:43

which are mineralized,

4:45

one of which is approaching 10.

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They had myelinic edema,

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likely from vigabatrin therapy,

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that the myelinic edema resolved

4:54

after cessation of the therapy.

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Why do I mention the lesion burden?

4:59

Well,

4:59

there's not a one-to-one correlation between the

5:02

amount of dysplasia someone

5:04

has and their seizures.

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But the more areas of dysplasia someone has,

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the more likely they are to have seizures,

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the more likely they are to have severe

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and uncontrolled seizures.

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They may have more different types of seizures.

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They may have seizures that are

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refractory to medication,

5:19

and also a higher degree of lesion burden tends

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to correlate with a lower degree of

5:26

intellectual functioning. Again,

5:28

every individual is different. It.

5:30

But these are findings that can help guide

5:33

the neurologist in the family,

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especially when there's a young child,

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and you don't know how bad their seizures will

5:40

be or what their intellectual

5:42

development will be.