0:01

Alrighty. So the case number five,

0:06

most of y'all got,

0:08

and you identified this lesion at the,

0:13

at the jugular foramen.

0:15

Many of you use the term the salt and pepper appearance of

0:20

the lesion with vascular flow signals within it.

0:25

And that can apply to the post ga, it can apply to the

0:30

T two way image. Um, this is, um,

0:35

cresh kind of labeled this in, in different ways.

0:37

There is a component of this that gets to the petras apex.

0:42

Here's our Petri internal carat artery,

0:50

but the lesion is more centered inferiorly.

0:53

Here's our hypoglossal canal. And as you can see, the,

0:57

these lumous tumors are in close approximation to where the

1:02

12th perennial nerve is coming out.

1:05

And sometimes it will erode this little bony strutt between the gloma, uh,

1:10

the framer, the jugular foramen, and the hypoglossal canal.

1:15

This would be that little bird beak that you sometimes see that people refer to

1:19

on the coronal ct. Um,

1:24

what you also wanna look at is whether the lesion

1:29

is infiltrating the jugular vein.

1:33

So in most cases, here's your carotid artery.

1:37

In most cases, the tumor will grow into the jugular vein.

1:41

Here's our normal jugular vein here. Here we have, uh,

1:46

I think a displaced, um, vessel,

1:49

but probably not the jugular vein.

1:52

'cause usually these tumors grow into the jugular vein.

1:56

And remember that we're,

1:58

we're in the high carotid sheath and that's where the ninth, 10th,

2:02

11th perennial nerves are gonna be traveling as well as for a brief period,

2:06

the 12th perennial nerve.

2:08

So you could have symptom symptoms of perennial nerve pathology here,

2:13

um, from a lumous tumor,

2:16

a lot of times it is the clinical history that Siresh gave you,

2:21

which is pulsatile tinnitus. So let's look at our

2:28

cis imaging and um, you know,

2:31

it's not nice as nice as the post gad. This is the region.

2:36

You can see dark flow voice. Let me try to brighten this a little bit.

2:42

Yeah,

2:43

so here you can see some of those flow voids within the lesion to suggest that

2:47

this is a vascular lesion. Now I've gotten food.

2:51

I've gotten food with a renal cell carcinoma metastasis,

2:55

which is a hypervascular metastasis fibroid metastasis of the,

2:59

the skull base in this location. And so there is a differential diagnosis.

3:04

What you wouldn't wanna say is a schwannoma.

3:07

This is not kind of a oblong, well-defined lesion.

3:11

This is, has these infiltrative margins,

3:13

which make it much more likely to be a paraganglioma. Um,

3:18

again, we have our, uh, neurovascular anatomy with the,

3:23

uh, 12th nerve coming into hypoglossal canal.

3:28

Here is our 9 10 11 complex coming into

3:33

jugular foramen or

3:38

seventh eighth nerve complex. Our fifth nerve here, it's fine.

3:43

Here's our sixth cranial nerve going into Della's Canal and

3:48

we don't get up to the, uh, midbrain level.

3:54

This is the coronal again, vascular flow voids,

3:57

irregular margination expansion. Um,

4:03

there was a, maybe I missed it on the, uh,

4:06

hypoglossal canal case. I should have shown you some, uh,

4:11

tongue atrophy. Um, in this case we don't have that.

4:16

Alright, we lost that. Let's go back to case number one.

4:20

I think on the coronal, there's some

4:27

case number one

4:32

seeing it, but on one of the cases there was

4:36

some atrophy of the, um, ipsilateral uh, tongue.

4:42

Okay, so, uh, case number five,

4:46

see where we can get this.

4:50

Here's that coronal hypervascular mass.

4:53

Lemme just make sure we didn't see the tongue.

4:56

One of these cases had tongue actually. Okay, so, um,

5:02

anything else in the differential diagnosis? Um, you know,

5:06

it's usually schwannoma versus, uh, paraganglioma on,

5:09

on this in this location. Metastases,

5:14

hypervascular metastases is in the differential diagnosis. Um,

5:20

yeah, that's probably it. Let's see whether we have a,

5:24

um,

5:26

reference to the paragangliomas on the article that we're gonna

5:31

send you.

5:33

So I think there was a portion portion here where it said vascular regions

5:39

paragangliomas. Okay, here's our paragangliomas. Uh,

5:45

locally aggressive,

5:47

not like a schwannoma enhancing soft tissue. Punctate serpentine things,

5:53

that's the salt and pepper look sometimes

5:56

Hemorrhage. Yeah, classic salt and pepper figure 19.

6:02

Okay, so this a little bit more. Yeah,

6:07

so here we have the lesion little flow voids within it.

6:11

Irregular margination, unlike a schwannoma. And uh,

6:16

here you can see that this one's affecting the, you know,

6:20

the hypoglossal canal as well as the jugular angum.

6:25

So right side postal tinnitus, it could have been exactly our case.

6:35

Alright, so that was the last case, right? Postal tinnitus, uh, Dr.

6:40

SSO for this ggl, Mr. Giri,

6:41

the standard answer states that there is right facial nerve enhancement,

6:46

suspicious of infiltration. Is it common for gloma to involve the facial nerve?

6:51

No, it's not common for the gloma to involve the facial nerve.

6:55

It would have to be relatively extensive to involve the stylo mastoid foramen as

6:59

the, as the seventh grader nerve exits and or,

7:05

um,

7:05

erode at the level where the descending or intra mastoid portion of the,

7:10

uh, facial nerve will um, come out. Um,

7:16

let's see whether we can identify that facial nerve enhancement that we were

7:21

referring to. So, um,

7:26

I think this is where Resh is talking about the facial nerve enhancement.

7:30

There's an article that is the classic article

7:35

about facial nerve enhancement.

7:38

And it is by Steve GSKi, who is a contemporary of mine,

7:44

who wrote an article early in MR.

7:49

That everyone cites.

7:50

And what GSKi wrote was that the

7:55

tympanic portion of the facial nerve normally

8:00

can enhance and it may enhance asymmetrically.

8:04

And he wrote that the descending portion of the facial nerve

8:12

can enhance and it may enhance asymmetrically.

8:17

So when we look for at facial nerve enhancement,

8:21

we know that intracanicular or labyrinthine,

8:27

pre ganglionic facial nerve does not enhance.

8:31

That's what ga barski noted.

8:33

No enhancement of the I A C or the fallopian canal

8:38

portion of the facial nerve before the geniculate ganglion.

8:41

The geniculate ganglion often does enhance and then we know

8:46

that typa and int mastoid may or may not enhance it.

8:50

It's variable and it's asymmetrical quite often. So when you're looking at,

8:54

at facial nerve pathology in the tympanic and intra mastoid portion,

8:59

you have to look for a enlargement and enhancement.

9:04

But enhancement itself is not pathologic.

9:08

So this is the classic article that everyone refers to.

9:14

It's published in radiology by Steve Varsity.

9:20

And what he says in here, um,

9:24

he looked at 186 facial nerves 142 visibly enhanced.

9:29

So at least one segment of the facial nerve in the facial canal.

9:32

And there is right left asymmetry in 69%.

9:36

So the fact that one side enhances but the other side doesn't enhance,

9:40

does not help you. That's it.

9:42

It occurred in at least some asymmetry in 69%.

9:49

The facial nerve in the c p angle in the I A C as well as in the

9:54

proximal portion of the extra cranial facial nerve showed no

9:58

enhancement. So that's,

10:01

he's referring to IIC as well as proximal to the gen

10:05

ganglion, no enhancement.

10:09

This enhancement corresponding exactly to the topography of the circle neural

10:13

facial nerve plexus and should not be considered a sign of abnormality.

10:19

So this is it. I mean, as you can see it's kind of an old article.

10:22

Here's the circum neural plexus that you refers to with a diagram.

10:28

These are, as you can see, kind of old, old article, you know,

10:33

showing the chin ganglion and the mastoid portion of the facial nerve.

10:38

And, um, the greater super superficial roal nerve,

10:43

which comes off of the gli ganglion enhancement,

10:47

is asymmetric and in homogeneous

10:51

and one side more than the other. You can't even tell if on these old, uh,

10:56

images, but that's

11:01

pretty common.

11:04

So gadolinium enhancement along the facial nerve and the facial canal is

11:06

frequently seen in the patients by facial canal,

11:09

means the tpan and intravascular portions.

11:11

Even if such enhancement is in homogeneous and or asymmetric on the right and

11:15

left nerves,

11:16

this enhancement is probably the result of the gadolinium in the ural venous

11:20

plexus that occurs there. Okay, so don't call it abnormal.

11:26

So in, in this case, this,

11:29

this lesion is just quite large.

11:33

And you may worry about right here,

11:37

this is the tylo mastoid foramen here and

11:42

here where there is tumor there that may affect

11:47

the seventh cranial nerve,

11:48

which you wanna do When you see that is you wanna look at the, uh,

11:52

the plAsa muscle. If it's asymmetric, that would suggest that it, that it is.

11:56

You wanna look at the clinical history and see whether the patient has a facial

12:00

nerve palsy.