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This is a CT scan and some MR images in

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a three-year-old child with a seizure,

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and the patient happens to have a

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birthmark on the right side of their face.

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If we look up on the CT scan,

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we're seeing this area of increased

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density along the cortical margins.

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And we're overlaying it, we're seeing slight

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prominence of the CSF space as compared to the

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contralateral side, suggestive of volume loss.

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If we look at the MR, we see

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confirmation of volume loss.

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We're also seeing what looks like

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asymmetric prominence of the diploic

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space overlying this area of volume loss.

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This is in the overlying areas

0:55

of the right frontal bone.

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This prominence of the diploic space

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is known as the Dyke Davidoff Masson

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phenomenon, where chronic volume loss

1:04

results in focal prominence of the diploic

1:08

space overlying the region of volume loss.

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Possibly could be thought of as a

1:14

compensatory way to fill in some of the space.

1:18

The underlying brain, we're

1:21

seeing cortical thinning.

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and loss of subcortical white matter.

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If we go to the T1 post-contrast image, we're

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seeing here these linear areas of enhancement

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representing transmantle veins, veins that

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go from the cortex to the deep venous system.

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We're also seeing Linear leptomeningeal

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enhancement overlying some of the areas

1:51

of cortical thinning and volume loss.

1:55

Well, why is this?

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If we look on the T2-weighted image again,

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beyond the brain, where we see less

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than we normally would in this region, and

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beyond the overlying bone, where we talked

2:09

about the Dyke David Auf Messon phenomenon,

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in between, we can see cortical veins.

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predominantly drain the cortex.

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They're a part of the superficial

2:18

venous drainage system.

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Notice overlying this region of volume loss,

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we're not seeing signs of cortical veins.

2:27

The brain cortex has a smaller

2:29

volume than the white matter, but it

2:31

is much more metabolically active.

2:34

So therefore it has significant

2:35

need for venous drainage.

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In the absence of venous drainage, because of

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the no cortical veins overlying this region,

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what happens to the draining venous blood?

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Well, you can have transmantle collaterals

2:54

going to the deep venous system, or you

2:57

can have leptomeningeal collaterals that

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take it almost laterally to get the blood

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to a region where there are cortical veins.

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What does that do?

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That allows there to be venous drainage.

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But in the absence of the normal venous

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drainage, you get chronic venous congestion.

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What happens with chronic venous congestion?

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It results in chronic venous ischemia, results

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in volume loss, and dystrophic mineralization.

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The dystrophic mineralization can also

3:31

be seen on susceptibility weighted

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imaging, where we see this ribbon-like

3:36

susceptibility hypointensity along the cortex.

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This actually allows us to see it with better

3:44

delineation than we do on this CT scan, even.

3:48

So this chronic venous ischemia results

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in transmantle collaterals, chronic

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venous ischemia, volume loss, and one

3:59

analogy I've heard that's relevant is

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that calcium is the tombstone to an

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if you think about it like that, these

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areas with dystrophic mineralization,

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there has been injury to the brain.

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That's why there's been volume loss.

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Injured brain has the propensity

4:18

of being epileptogenic.

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So the patients get seizures.

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This vascular abnormality with the resultant

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volume loss and dystrophic mineralization

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and abnormal venous collaterals ends up

4:32

being ipsilateral to the facial birthmark.

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This is known as

4:38

encephalotrigeminal angiomatosis.

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Encephalo for brain, trigeminal

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because the birthmark is in the

4:45

trigeminal nerve distribution.

4:47

Angiomatosis because of the blood

4:49

vessel proliferation here and

4:52

abnormalities in the venous drainage.

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So encephalo-trigeminal angiomatosis

4:56

is the more formal or medical

4:59

name for Sturge-Weber syndrome.

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So this patient has Sturge-Weber syndrome.