0:00

This is a very important case to analyze, and I want this

0:06

case to be burned in your hippocampus for the future.

0:11

Here we have a patient on a T1-weighted scan that

0:15

shows some opacification of the paranasal sinuses.

0:19

You might note that it looks like the nasal septum

0:21

is not well defined here on the T1-weighted image.

0:26

But otherwise, maybe a little bit of hyperintensity

0:30

to the secretions, not too dramatic, and the maxillary

0:34

sinus looks pretty good other than on the right side.

0:37

When we look on the T2-weighted scan, we notice

0:39

that there is some dark signal intensity along

0:42

that nasal septum that was not appreciated

0:47

on the T1-weighted image. This darker

0:49

signal intensity in the sphenoid sinus,

0:52

a little bit of fluid, maybe inflammation. The ethmoid

0:56

sinuses, at first blush, and just looking at the T1-

1:00

and T2-weighted images, we might dismiss this

1:03

as, you know, chronic sinusitis,

1:06

not too impressive looking.

1:09

However, when you look at the post-gadolinium

1:13

T1-weighted image, it's pretty striking

1:17

that we are not seeing mucosal outline

1:21

of enhancement.

1:23

Normally, the mucosa, as you can see, shows

1:26

enhancement on the surface of the mucosa.

1:29

If we look at the anterior ethmoids here,

1:32

that's what normal sinusitis looks like.

1:34

It's got a little bit of enhancement

1:36

on the surface of the sinus.

1:38

Note that here we have effectively necrosis.

1:42

We've lost the normal anatomy of the

1:45

nasal septum.

1:46

We've lost the enhancement of the medial walls

1:49

of the sphenoid sinus and the ethmoid sinus.

1:52

This posterior ethmoid sinus and sphenoid sinus again.

1:56

Where is the normal mucosal enhancement

1:58

that defines the walls of the sinus?

2:02

They're gone.

2:02

Look at this here.

2:03

It's a normal appearance laterally.

2:07

But anteriorly and on the right side,

2:09

we've lost the outline of the sinus.

2:12

This is one of the very characteristic features

2:15

of the invasive form of fungal sinusitis.

2:19

It leads to necrosis of the walls of the sinus.

2:23

Not only that, but when it is as aggressive as you're

2:26

seeing here, you really have to worry about

2:29

the cavernous sinus.

2:31

So if you look on the lateral wall of the left

2:34

cavernous sinus, we see that the carotid artery

2:36

is nicely outlined here, and we can see the

2:39

enhancement of the cavernous sinus on the right side.

2:43

We've lost that lateral wall of the cavernous sinus.

2:47

It's no longer enhancing.

2:49

This is aggressive, invasive mucormycosis

2:54

of the paranasal sinus, which is leading to

2:57

cavernous sinus thrombosis.

3:00

On the right side, you notice also the

3:05

difference in the caliber of the carotid artery

3:08

on the right side compared to the left side.

3:11

I think that this was also evident

3:12

even on the non-contrast scan.

3:15

This is invasion of the wall of the right cavernous

3:21

carotid artery, causing it to be narrowed and the

3:24

wall to be enhancing in association with the reduction

3:29

or absence of the enhancement of the cavernous

3:31

sinus. Aggressive, invasive mucormycosis with

3:37

necrosis of the paranasal sinuses, as well as

3:41

infiltration of the right cavernous sinus with

4:44

associated vasculitis of the internal carotid artery.

3:49

This can lead to thrombosis of the right internal

3:54

carotid artery and subsequent infarction.

3:59

That's the high risk of a patient who

4:01

has diabetes or is immunocompromised with

4:05

aggressive, invasive fungal sinusitis.

4:09

When we look at the diffusion-weighted images of this

4:13

case, we notice that the patient has areas of

4:17

restricted diffusion within the anterior cerebral artery

4:20

distribution, as well as around the caudate nucleus,

4:23

which may be the artery of Heubner distribution, but there

4:27

is infarction here, and that infarction is secondary

4:30

to the aggressive invasion of the vasculature from the

4:35

cavernous sinus and the cavernous carotid artery to

4:38

the anterior cerebral artery from the fungal sinusitis.