0:01

So indeed this was the, uh, next case.

0:04

And for those people who are not familiar or

0:09

frequently look at the diffusion

0:14

wave scans for cerebella,

0:16

pontin angle cistern lesions, uh,

0:20

this is probably instructive. Here's our standard T two way scan,

0:24

which I must admit when I was looking at this, uh,

0:28

it's a pretty hard call here.

0:29

There's a lot of stuff that goes on in the CP angle,

0:32

including as you see on the right side, C ss f pulsation artifacts,

0:37

and those will also abound on the flare scan. Alright,

0:42

but let's look at this and then I'll, I'll reload. So on the D W I,

0:46

what you see is something bright here, which should not be there when you, um,

0:50

and it's extra axial. So when you find something like this,

0:54

you're gonna look at all the other post sequences because you can have like, uh,

0:59

diffusion shine through lesions, which include things like hemorrhage.

1:04

Um, often, um, you'll see, uh,

1:08

blood products that have what looks like restricted diffusion,

1:12

except that it's, um, all betts are off when you have hemorrhage and,

1:17

and you're trying to interpret the D W i, uh, lesions.

1:22

So the problem with the flare, as I said,

1:24

is that that's a location where we frequently get

1:29

C ss f pulsation artifacts. And it, it can be kind of tricky. Same thing,

1:35

you know, down in the posterior phos,

1:37

anywhere in the posterior fossa you may have that issue.

1:41

So as we come down here,

1:46

this is the area of concern

1:51

and, you know, you see all this stuff up the anteriorly.

1:56

Again, c s f pulsation artifacts. We know that because, um, well,

2:00

we saw that the D W I abnormality was at this, at the, um,

2:04

CP angle in I A C. Um, if you go to the CYS imaging,

2:12

sometimes it cleans it up,

2:16

but cyst is another pulse sequence that has a lot of fluid sensitivity.

2:21

So clearly on the, uh, cyst image,

2:26

you can see that there's something extra here that is actually

2:31

on both sides of the CP angle with the cranial nerves seeming to

2:36

be in almost encased on this, on these images.

2:43

And again, we're talking about the seventh,

2:45

eighth nerve complex as we go to the internal auditory canal. Now,

2:49

in this specific case,

2:52

we don't have very much in the way of pulsation artifact on the CYS image,

2:56

which is happy. Um, but it, it's unusual.

3:02

Okay, fifth cranial nerves. Once again,

3:04

there is a little bit of the tissue right here that is a budding,

3:09

the lateral aspect of the fifth cranial nerve.

3:12

We have the lesion going intimately associated with the seventh eighth

3:17

nerve complex. This is our 9 10 11 complex,

3:22

which is free of the disease and we don't get down to

3:26

hypoglossal here. Again, six cranial nerves,

3:30

six cranial nerve coming into me, uh, Dre's canal.

3:35

And then from there we'll go up into the Cabernet science and we,

3:39

we miss out on the, uh, third cranium nerve.

3:44

So, um, I think this,

3:49

I didn't find the a d C nearly as helpful.

3:53

You can see that there's something in there and it's,

3:57

it's hard to say whether this is restricted diffusion. It,

4:00

it's almost iso intenses to the, um,

4:05

Rebell Ponte Ingle, uh, to the middle cerebellar Pete uncle.

4:10

But the D W I, I think is convincing and, um,

4:14

so is the cysts.

4:16

So is I think you get a sense that we are

4:21

embracing the cyst imaging very much in, in regard to,

4:25

um,

4:26

evaluation of nerve of lesions that may affect the cranial

4:31

nerves. And actually in their visualization, this,

4:35

this epidermoid was very well seen on the, uh, cyst image.

4:38

So if you're not familiar with that pulse sequence already, uh,

4:42

you ought to spend some time.

4:44

I will give you the name of Ari Blitz who has written about that

4:49

pulse sequence in cranial nerve pathology in the various, uh,

4:53

radiologic clinics of North America and M r i clinics of North America and Neuro

4:58

Imaging Clinics of North America. So if you need a, uh,

5:02

reference just B L I T Z A

5:08

and constructive interference Study state. So, um,

5:12

let's go back to the article and just

5:20

look at that case that they had. So in this,

5:25

in this article,

5:27

they are contrasting the

5:32

epidermoid cyst with the next case, which is, uh,

5:36

a pure retinoid system. You see on the, uh, this is the a d C map,

5:41

how it's a normal,

5:44

it's just C ss f signal intensity on the a d c map,

5:47

you'd expect the lesion to be somewhat dark here.

5:54

Okay, so good article,

5:56

Good case, good demonstration of cysts. And again,

6:00

spend some time describing the anatomy so that way the surgeon knows

6:04

where to find the lesion. You know, it's, it's against the back wall of that,

6:09

you know, fifth radial nerve. Uh, as well as

6:15

the importance of being able to talk to the patient and saying,

6:19

this lesion's abutting the fifth cranial nerve.

6:23

I don't expect you to have fifth cranial nerve symptomatology after surgery,

6:28

but there's a chance that as we scrape it off of the fifth cranial nerve,

6:31

you will have either sensory problems immediately after surgery

6:36

or muscles of mastication problems. Um,

6:41

so that's something to be concerned about as well as the seventh and eighth

6:44

brain nerves involvement.