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Hello and welcome to Noon Conference, hosted by Modality

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Today we are honored to welcome Dr.

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Mohi Aggarwal for a lecture entitled Orbital Pathologies.

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Dr. Aggarwal is an associate professor of neuroradiology

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and program director

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of the Neuroradiology Fellowship Program at the Medical

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College of Wisconsin Milwaukee.

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He is a passionate educator who has been repeatedly honored

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for his teachings by fellows, residents,

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and medical students at MCW

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and recently received the A three CR two outstanding teacher

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award from the A a R.

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He founded the Cortex Club, an online community

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that enhances neuroradiology education

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through weekly quizzes, video lectures,

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and sessions by world renowned educators.

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Dr. Agarwal clinical and research interests include Head

1:07

and neck and Dementia Imaging,

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and he's actively involved in

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R-S-N-A-A-S-N-R-A-S-H-N-R-A-C-R,

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and the a RRS At the end of the lecture, please join Dr.

1:19

Agarwal in a q

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and a session where he will address questions you may

1:23

have on today's topic.

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Please remember to use the q

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and a feature to submit your questions so we can get to

1:28

as many as we can before our time is up.

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With that, we are ready to begin today's lecture. Dr.

1:33

Agarwal, please take it from here.

1:36

Thank you very much for that introduction.

1:38

Uh, thanks to modality for this invitation.

1:41

Um, today we are gonna be talking about orbital lesions, so

1:45

that's what we are gonna talk about today.

1:47

Orbital lesions. I have no disclosures.

1:50

So, um, what are the objectives?

1:53

So in the next 40 minutes

1:54

or so, we are gonna be learning about

1:56

and recognizing some of the common orbital pathologies.

1:59

We learn about salient features of each entity

2:01

and try to differentiate different kinds of orbital lesions,

2:04

you know, inflammatory vascular,

2:06

neoplastic, uh, what have you.

2:09

And when we are talking about, um, you know,

2:11

orbital lesions, the common approach to, um,

2:15

to approaching orbital lesions is

2:17

by compartmentalizing these lesions.

2:19

So commonly you will, um, see that the lesions are described

2:23

as precept or post septal intracon, cornal

2:26

and extraoral lesions involving the globe

2:28

or lesions involving the optic nerve sheath complex.

2:31

And there is kind of a dual, uh, role

2:34

of describing these lesions according to the compartments.

2:37

One is that, of course, it helps the treating physician

2:40

or the treating surgeon to know where the lesion is.

2:42

And number two is that specific lesions

2:45

or different lesions have more propensity

2:47

or more likelihood of being in a certain compartment.

2:51

So when we are, um, you know, describing orbital lesions,

2:54

it really helps us to compartmentalize these lesions.

2:58

So the first, uh,

3:00

approach at looking at an orbital lesion is

3:01

to decide whether the lesion is pre septal or post septal.

3:05

So when we are talking about the septum, you know,

3:08

let's take a look at, at what the septum looks like.

3:10

What is the orbital septum?

3:12

Orbital septum is nothing,

3:13

but let me turn on my laser pointer.

3:16

So the orbital septum is nothing

3:18

but a reflection of the periosteum of the orbit

3:20

of the periorbital,

3:22

and it extends inferiorly from the orbital margin.

3:24

You can see that orbital septum, this thin line on the ct.

3:28

Similarly, on this Mr image, you can see

3:30

that this thin reflection, this thin, um, uh, sort of,

3:35

uh, septum, uh, uh, extends from the margin of the orbit,

3:39

and then it attaches to the lator, alpi, superiors, aosis,

3:44

and then it inserts onto the eyelid

3:45

and then thickens to form the tosil plate.

3:48

You can also visualize this orbital septum on an axial image

3:51

on the mr uh, on an axial image.

3:54

The lator apiary a neurosis

3:56

and the orbital septum sort of look as one.

3:58

So the lator, a neurosis kind of is a good landmark to know

4:02

where the orbital septum is.

4:05

So any lesion that is anterior to that, uh, to

4:08

that septum is a pre sepal lesion.

4:09

And anything that is posterior

4:11

to it is see post septal lesion.

4:13

Now why is that important?

4:14

Why are we talking about pre septal and post septal lesions?

4:17

For the simple reason that any process which is anterior

4:21

to the orbital septum or a pre septal process, for example,

4:24

here we are seeing some pre septal cellulitis.

4:26

We can see that all the inflammation

4:28

or the soft tissue thickening is anterior

4:30

to the orbital septum.

4:32

Again, we can see that this is the orbital septum,

4:34

and this process is anterior to the orbital septum.

4:36

So pre septal cellulitis is a much easier entity to treat

4:42

compared to post septal pathologies.

4:44

When the lesions extend posterior to the orbital septum,

4:47

these lesions are difficult to treat.

4:49

They can even require surgical exploration

4:52

and also post septal lesions have a higher

4:55

likelihood of complicating.

4:57

So they can be intracranial complications,

4:59

they can be extension into the whole orbit.

5:02

They can be extension into the orbital apex

5:04

and extension into the cavernous sinuses.

5:06

You know, they can be subdural, empyema,

5:08

cellebrite as what have you.

5:10

So the, the, the chances

5:12

of intracranial complications is much higher in post

5:16

septal lesions, number one.

5:17

And of course, there are, they are more difficult to treat.

5:20

So that is why it is important

5:21

to differentiate a pre septal lesion from a

5:24

post septal lesion.

5:25

Now, most pre and post septal cellulitis is, uh,

5:29

because of sinusitis, inflammation of the sinuses

5:31

that is extension of the sinus infections

5:34

into the orbit commonly.

5:35

Uh, and one thing, uh, to remember in, in, in this kind

5:39

of extension of sinus disease into the orbit, is

5:41

that bone erosion is not necessary for sinusitis

5:45

to extend into the orbits to cause orbital cellulitis

5:48

because there are valveless veins between the sinuses

5:51

and the orbits, and

5:52

that those valveless veins can carry the infective

5:55

material from the sinuses into the orbits.

5:57

For example, we see a case here,

5:59

there is orbital abscess in this,

6:01

and you can see that the bony septum between the sinus

6:03

and the orbit is well maintained.

6:05

There is no erosion of the bone.

6:07

So one thing to, to keep in mind when we are evaluating

6:10

extension of sinus disease into the, uh, orbits, then

6:14

what is, what is going on here?

6:16

So again, you know, we can see

6:17

that there is orbital cellulitis.

6:19

There is extensive ex, um, stranding of the orbital fat,

6:23

but this process is generalized.

6:25

You know, there is post septal infection,

6:27

but it has involved the entire orbit.

6:30

It has complicated

6:31

because we can see that there is extension into the

6:33

cavernous sinuses that is cave sinus, thrombo,

6:35

phlebitis bilaterally.

6:37

There is even some edema in the, in the brain stem here.

6:40

Uh, this patient also had subdural emus,

6:42

so this is complicated.

6:44

Um, orbital cellulitis, which tends to be more common

6:47

with post septal infections.

6:48

There is something else that is going on here.

6:50

You know, all this inflammatory soft tissue has increased

6:53

the pressure in the eye,

6:55

and this kind of process

6:56

where there is increase in pressure in the eye is known

6:58

as orbital compartment syndrome.

7:00

This is an orbital emergency,

7:02

and if you see this kind of, uh, picture

7:04

where there is proptosis that is stretching

7:06

of the optic nerve, you can see that there is stenting

7:08

of the globe that is stretching of the optic nerve.

7:10

It can cause damage to the, uh,

7:13

vascular structures of the orbit.

7:14

It can cause damage to the, uh, optic nerve itself.

7:17

So if you see this kind of imaging picture

7:19

where there is diffuse involvement of the orbit

7:21

with increased pressure within the orbit, in the form

7:23

of stretching of the optic nerve, tending of the globe,

7:26

this is an orbital emergency,

7:28

and you should always get in touch

7:29

with the treating physician, uh,

7:31

because these, these things need to be treated urgently.

7:35

So this, this was about pre

7:37

and post septal, um, uh, you know, infections or pre

7:40

and post septal sort of division of the processes.

7:43

The next thing that we tend

7:44

to describe in orbits is whether a lesion is

7:48

intracon cornal or extra cornal.

7:50

So what is that cone that we are talking about?

7:53

So, uh, the cone within the orbit is formed

7:56

by these extraocular muscles,

7:58

these extraocular muscles attached to the orbit

8:00

or the globe anteriorly

8:02

and attached to the annulus of Zi at the orbital apex,

8:05

and formed this muscle cone that sort

8:08

of forms a compartment within the globe.

8:10

And there are lesions that tend

8:11

to be more common in the intracon lesion

8:13

and, uh, intracon compartment.

8:15

And then there are lesions that tend

8:16

to be more common in the extra cornal compartment.

8:19

So number one, let's talk about lesions within the cone.

8:22

Let's talk about intracon lesions.

8:25

So this is, you know, here, here's an example of one

8:28

of those intracon lesions.

8:29

What we have here, let's, let's look at it together.

8:32

So here we have a coronal, uh, CT image and an axi CT image.

8:36

This is a post contrast image.

8:37

As you can see, there is enhancement

8:39

of the arterial structures of the, uh, the,

8:41

uh, vascular structures.

8:42

So this is a low density,

8:44

well-defined lesion in the intracon

8:46

compartment of the orbit.

8:47

On the post contrast images, we can see

8:49

that there is some peripheral enhancement on the mr, again,

8:53

a very well-defined lesion in the intracon le uh,

8:55

in the intracon compartment.

8:57

Um, it is very hyperintense

8:59

and kind of homogenous on T two weighted images.

9:02

On post contrast images.

9:03

We can see that there is some kind of wispy enhancement

9:06

that is starting to, um,

9:08

to fill up the lesion on this axial image.

9:10

And as we all know, at least, um, um, in my shop,

9:13

the coronal images are done a little bit

9:15

after the axial images,

9:16

and we can see that on the coronal sort of delayed images.

9:20

All this is trying to, uh, that the lesion is trying

9:23

to fill in and this kind of filling in

9:25

of enhancement from the periphery to the center.

9:28

These kind of lesions are common throughout the body.

9:30

You commonly see them in the liver, very common

9:32

where there is enhancement

9:34

of the structures from periphery to the center.

9:36

These were previously known as hemangiomas,

9:38

but you know, people have, have, um, investigated

9:41

and found out that these are not true tumors.

9:43

So these lesions are now known as venous malformations

9:46

or slow flow vascular malformations.

9:48

And this kind of cavernous venous malformation

9:51

or slow flow vascular malformation is very common in the

9:53

orbit, very common in the intracon compartment.

9:56

And this is the imaging appearance.

9:57

They're hyperintense on T two, they're well-defined.

10:00

They sometimes tend to increase width, uh, with time,

10:04

and they show this typical pattern of enhancement

10:06

of filling in from the periphery to the center.

10:10

Then here's another intracon lesion.

10:12

Again, we are seeing that this is, uh,

10:14

a lesion in the intracon compartment.

10:17

Um, uh, what, what is the characteristic?

10:19

You know, it, it is. So we,

10:20

we saw a vascular malformation previously.

10:23

You know, here's another lesion.

10:24

It, it is not as hyperintense as the other lesion was.

10:28

Um, it is kind of, uh, multis spatial, you know,

10:31

that was very well-defined.

10:33

This lesion is more like multi, uh, you know, um, it,

10:36

it is not as well defined as the previous lesion was.

10:39

The other thing that is striking about this lesion is

10:41

that it's showing small fluid, fluid levels.

10:43

So it's, it looks like it has multiple sort

10:46

of cystic compartments, some

10:48

of which are showing fluid, fluid levels.

10:50

Now, what do, what do we have on post contrast images?

10:53

And the post contrast images?

10:54

It looks like there is, you know, another smaller component

10:56

of the same lesion, and the enhancement is not as robust

11:00

or is not in the typical pattern

11:02

that we saw in the previous case.

11:03

You know, there is not that typical filling in that we saw

11:06

with a cavernous malformation.

11:08

What do we see on ct? On ct?

11:10

We are seeing this punctate areas of calcification,

11:12

and if we assume this is a vascular lesion,

11:14

these could be frees.

11:16

So when you, um, see this kind of imaging appearance,

11:19

this is more suggestive of aveo lymphatic malformation.

11:22

There are different kinds

11:23

of vascular malformation in the orbit.

11:25

There is of course the cavernous malformation,

11:27

but there are these different vascular malformation

11:30

that can have different capillary arterial

11:32

or venous components.

11:34

This is one such lesion where there is, uh,

11:36

a combined lesion from, uh, uh, the, the veins

11:39

and the lymphatic channels.

11:41

So these kind

11:42

of combined renal lymphatic malformations are

11:44

also common in the orbit.

11:45

And this is the emit appearance.

11:47

They are sort of multi lobulated multicystic.

11:50

So show fluid, fluid levels.

11:52

The enhancement characteristics depends upon, uh,

11:55

the relative component of how much, you know, venous, uh,

11:58

component there is, or how much, uh,

12:00

lymphatic component there is.

12:01

Lymphatic component, as you know,

12:03

is not going to enhance that much.

12:04

There is the venous component tends to enhance.

12:06

And because of the venous component, we tend

12:09

to see these free bullets in these lesions.

12:11

So renal lymphatic malformation, again,

12:13

a common lesion in the, uh, in the orbit.

12:16

Here's another case here.

12:18

We are seeing, you know, sort

12:19

of a lobulated lesion in the intracon

12:21

compartment of the orbit.

12:23

This actually, uh, this lesion has as kind

12:25

of a cool story behind it.

12:27

Uh, this patient came in with, uh,

12:29

for a non-contrast CT of the orbits.

12:31

Our tech saw this lesion, and they called the reading room.

12:34

They said, oh, we, you know, we have a lesion.

12:35

Do you want us to give contrast?

12:37

Now, another one of my astute colleague,

12:39

they looked at this lesion and they said, well, you know,

12:42

before we give contrast, can we perform well Salva,

12:45

because they thought this could be a venous varix.

12:48

And, and lo and behold, you know,

12:50

when we perform Val Salva in this patient,

12:52

this lesion really, um, uh, you know, um,

12:55

enlarged in size, uh, a lot.

12:58

And, uh, another lesion which we were not

13:00

able to see previously.

13:02

We, um, uh, you know, that that lesion also appeared.

13:04

So, you know, venous vase in the orbits

13:06

are also very common.

13:08

They are these lobulated things

13:09

that enhance just like veins.

13:11

They're homogenous and they tend to increase in size, width

13:14

with the Salva maneuver.

13:15

They can also change in size with the ity of respiration.

13:19

And if you follow these lesions over time, you will see

13:22

that there is always some variability of size

13:24

of these lesions on, on multiple, uh, images.

13:27

And that is simply because the phase

13:28

of respiration the patient is in during the time

13:31

of scan will alter the size of these of these lesions

13:35

with the lesions being, uh, uh,

13:37

larger when the patient is in the

13:39

expiratory phase of respiration.

13:41

This air, uh, within these, uh,

13:44

these varis is simply air from, from venipuncture that tends

13:48

to, um, uh, uh,

13:50

get into the venous structures when there is, uh, some air,

13:54

um, uh, introduced intra veins.

13:57

Then here we have another, um, intracon lesion.

14:00

Um, uh, you know, what does it look like?

14:03

This intracon lesion, you know, is, is sort

14:05

of more ill-defined.

14:07

It's, it's not as well-defined again as venous malformation.

14:10

It's not showing the multicystic kind of appearance

14:13

that we saw in, uh, veo lymphatic malformation.

14:16

It looks sort of more homogenous on T two,

14:19

has a very low T two signal.

14:22

And if, if we look at this lesion here, you know, it's,

14:25

it's kind of conforming to the shape of the, you know,

14:28

of the different structures that it is around.

14:30

You know, it is, uh, it is not really displacing anything,

14:33

but it's conforming to the shape,

14:35

very homogenous enhancement on, on these coronal

14:38

and axial images.

14:39

And this is showing some kind of restricted diffusion

14:42

as well, you know, that is reduced diffusivity.

14:44

So I've been talking about lesions

14:46

and compartmentalizing orbital lesions into, um, you know,

14:49

different compartments and saying that, you know,

14:51

some lesions are common in some compartments,

14:53

but there are certain lesions that do not respect boundaries

14:56

and can be present anywhere.

14:58

This is one of those lesions

14:59

that does not respect boundaries.

15:01

You know, it is homogenous, it is low, uh, in T two signal,

15:05

which indicates that it is a hypercellular lesion

15:07

and it is showing reduced diffusivity.

15:10

These kind of lesions

15:11

that are higher in cellularity show reduced diffusivity

15:14

and have this homogenous kind

15:15

of enhancement without significant displacement

15:18

of the structures around.

15:19

It is a, is a sort of a characteristic, um,

15:23

imaging appearance of orbital lymphomas

15:25

and orbital lymphomas are those lesions

15:26

that do not respect boundaries.

15:28

You know, they can involve the intracon compartment,

15:30

they can involve the extra conal compartment,

15:32

they can involve the extraocular muscles.

15:35

They can be, you know, an, um,

15:37

just thickening of the muscles.

15:38

They can, they can involve the orbital fat.

15:40

So this is one of those lesions that does not, uh,

15:42

respect the compartments,

15:44

but can very well be in the differential diagnosis

15:47

of an intracon lesion.

15:49

We just have to, uh, sort

15:50

of differentiate it from the other lesions that we just saw.

15:54

Then here's, here's another lesion

15:56

that does not respect compartments.

15:59

Uh, you know, this lesion is very much in the intracon

16:02

compartment, uh,

16:03

but also extends sort of, uh, um, laterally here.

16:06

Uh, this, this patient presented with orbital pain.

16:09

Again, when we look at this lesion,

16:11

it does not look like a typical, um,

16:13

Cavs venous malformation.

16:14

This is not looking like the,

16:16

the ven lymphatic malformation that we saw.

16:18

There is no multicystic appearance, no fluid fluid levels.

16:21

In fact, this lesion is showing some inflammatory features.

16:24

You know, even beyond, uh, the lesion itself.

16:27

We are seeing that there is some fat stranding.

16:29

There is extension of all the soft tissue to the other side,

16:32

and this patient presents with orbital pain.

16:34

So when you have this kind of clinical picture,

16:37

patients presenting with proptosis orbital pain,

16:39

and they have this ill-defined, uh, soft tissue

16:42

with inflammatory features in the orbit,

16:44

always think about idiopathic orbital inflammatory syndrome

16:48

or idiopathic orbital inflammation, also known

16:50

as orbital pseudotumor.

16:52

They are the second lesion, uh,

16:54

that do not respect boundaries.

16:56

They can be present in any compartment of the orbit.

16:59

They can involve the, you know, intracon compartment.

17:02

They can involve the extraocular muscles,

17:04

they can involve the lacrimal gland.

17:06

But the differentiating feature from orbital lymphoma,

17:09

which also tends to do all these same things,

17:11

is in the clinical picture.

17:13

So patients with lymphoma usually present

17:15

with painless proptosis, whereas patients

17:17

with orbital pseudo tumor tend to present

17:19

with acute orbital pain and proptosis.

17:21

So, um, that's one of the features

17:23

how you can differentiate an orbital lymphoma from an

17:26

orbital pseudo tumor.

17:27

The other thing that orbital pseudo tumor tends

17:30

to do is produce this inflammatory soft tissue that is

17:33

around the, um, around the lesion itself.

17:35

So that's also one of the things that could, uh, clue you

17:38

to the diagnosis of an orbital pseudo tumor.

17:43

And, and when you have, you know, this, this, uh, uh,

17:45

inflammatory soft tissue in this, uh, location

17:47

that is at the junction of the globe and the,

17:49

and the optic nerve, you also call this episcleritis.

17:55

Then we looked at pre septal and post sepal lesions.

17:58

Uh, we looked at intracon lesions, you know,

18:01

cavernous venous malformation being one

18:02

of those venal lymphatic malformations, venous varice.

18:06

And then we talked about two lesions

18:08

that do not respect boundaries.

18:09

That is orbital lymphoma and orbital pseudotumor.

18:12

Now, we come onto the cornal lesions

18:15

or simply put the lesions

18:16

that involve the extraocular muscles, cell lesions, uh,

18:20

that cause thickening of the extraocular muscles.

18:23

And this is one of those lesions.

18:25

You know, here we are seeing that there is thickening of the

18:28

inferior and medial rectus muscle.

18:30

Uh, also part of the, uh,

18:31

also the superior rectus muscle is thickened,

18:34

and this is bilateral, you know, this thickening

18:36

of the inferior and medial rectus muscles is bilateral.

18:39

That is also maybe some thickening with the superior rectus,

18:41

but more on this side.

18:42

So a bilateral, uh, involvement

18:45

or bilateral thickening of extraocular muscles, uh, in,

18:49

in this, uh, person.

18:51

And also the, the other imaging feature that is, uh, sort

18:54

of unique about this particular entity is that

18:56

although there is thickening of the muscle belly, the, uh,

19:00

the myo tendonous junction is spared.

19:01

So there is no thickening of the insertion

19:04

of the myo tendons junction of this muscle.

19:06

And this, as you all know, you know, it's, it's, um, sort

19:09

of, I've said all the buzzwords

19:10

about this particular entity.

19:12

This is thyroid, orbitopathy

19:13

or thyroid, um, you know, thyroid, uh,

19:17

myositis, so to speak.

19:18

And this thyroid orbitopathy tends to be bilateral

19:21

because it's a systemic disease,

19:23

and it fo follows this particular course

19:25

where there is involvement of the muscles in this sequence.

19:29

So there is involvement of the inferior, rectus,

19:31

medial rectus, superior, rectus, lateral rectus.

19:34

And finally, there is o uh,

19:35

involvement of the oblique muscles.

19:36

So I am slow is a good mnemonic to, uh, to evaluate, uh,

19:41

thickening of the extraocular muscles

19:42

and if the thickening

19:44

of extraocular muscles happens in this particular sequence,

19:47

and if it's bilateral without involvement of the myo tendon

19:50

as junction, think about thyroid orbitopathy.

19:53

Now, thyroid orbitopathy is, um, you know, is,

19:57

it can be generalized.

19:58

It can involve all the ocular muscles in, in the later form,

20:02

and it can produce what we talked about previously.

20:05

Thyroid orbit. Apathy can cause orbital compartment

20:08

syndrome, where the thickening

20:09

of the ex extraocular muscles tends

20:11

to increase the ion in the orbit.

20:12

They, it can cause crowding

20:14

of structures at the orbital apex can cause

20:16

compression of the optic nerve.

20:17

They can be proptosis tenting up the globe.

20:20

And again, if you see all those features, uh,

20:23

if you see development of, uh, orbital compartment syndrome,

20:26

definitely tell your clinician

20:27

because that might require, uh, orbit for,

20:31

uh, for decompression.

20:34

Now, thyroid orbitopathy is in direct competition

20:37

with another diagnosis, um, which, which is this one.

20:41

So again, you know, we are seeing that there is, uh,

20:43

thickening of the extraocular muscles.

20:45

Uh, incidentally, there is thickening of the inferior

20:48

and medial rectus muscles here, which tends to be

20:50

with thyroid orbitopathy.

20:52

But there are certain features here that do not confirm, uh,

20:55

or conform to the, um, uh, to the pattern

20:58

of thyroid orbitopathy.

20:59

Number one, there is a lot of inflammatory soft tissue

21:01

around these thickened muscles.

21:03

Number two, this is not bilateral.

21:05

It tends to be a unilateral disease.

21:07

And number three, you know, there is thickening

21:10

of the myo tendonous junction here.

21:11

So, although to begin with, you know, just, just, um,

21:15

at a glance, it might look like thyroid orbitopathy

21:17

because there is involvement of the inferior

21:19

and medial rectus muscles.

21:20

There are a lot of features in this case

21:22

that are not really consistent

21:25

with thyroid orbitopathy in this kind of picture,

21:27

especially if the patient is presenting

21:29

with painful proptosis.

21:32

Is, is sort of characteristic

21:33

of idiopathic orbital inflammatory, pseudo tumor

21:36

or idiopathic orbital inflammation.

21:38

There is inflammatory soft tissue in these cases.

21:40

These, uh, uh, this entity tends to be unilateral.

21:45

It can be bilateral, but more commonly unilateral.

21:47

And there is involvement

21:48

of the myo tendonous junction in orbital pseudo tumor.

21:52

And here's another example, another, you know,

21:54

side-by-side comparison of thyroid orbitopathy

21:57

and myotic orbital pseudo tumor.

22:00

This disease is bilateral, whereas this is unilateral,

22:03

this tends to follow a, a certain, um, uh, course, you know,

22:06

um, I am slow, this case did follow it,

22:09

but not all cases of pseu tumor are going to follow it.

22:11

And there is involvement of the myo tendons junction in, uh,

22:15

uh, so pseudo tumor, which tends not to be the case with

22:19

thyroid orbitopathy.

22:22

Then another example of, uh, thickening

22:26

of the extraocular muscles.

22:27

You know, here we are seeing that there is thickening of the

22:31

inferior oblique muscle.

22:32

Inferior oblique muscle is thickened.

22:34

Uh, you can see that in every, um, every image.

22:36

So what could this be? You know, our more, the most common

22:40

cause for thickening

22:42

of the extra muscles is thyroid orbitopathy.

22:45

But you know, number one, that tends to be bilateral.

22:47

This disease is not bilateral.

22:48

Number two, that tends to follow the Im slow course.

22:52

Here, there is involvement of the inferior oblique muscle,

22:54

not the inferior rectus.

22:56

So not really consistent with thyroid orbitopathy.

22:59

Could this be orbital pseudo tumor?

23:01

Maybe we are not talking about orbital pain,

23:03

though this patient did not present with pain.

23:05

So orbital pseudo tumor in the absence

23:06

of pain would be unusual.

23:08

The other thing that is, uh, different

23:11

or not consistent with orbital, uh, pseudotumor is that

23:15

the thickening there is thickening

23:16

of the extraocular muscle, but there is no inflammatory

23:19

stranding or inflammatory soft tissue around the muscle.

23:23

So this is not even consistent with orbital pseudo tumor.

23:27

This is more homogenous.

23:29

You know, this is, this kind

23:30

of looks like a previous case that we saw.

23:32

There is low T two signal,

23:34

and there is homogenous enhancement of this muscle.

23:37

This kind of homogenous enhancement along

23:40

with low T two signal is a feature that we commonly see

23:43

with orbital lymphoma.

23:44

So, again, as I said previously, orbital lymphoma

23:47

and orbital psal tumor do not follow any compartment.

23:50

They can be present in, uh, in any disease.

23:54

And this is one of those examples

23:55

where the orbital lymphoma, which is usually mal lymphoma,

23:59

um, involves the extraocular muscles.

24:01

So this is a muscle involvement variety of the, uh,

24:04

of orbital lymphoma.

24:08

And here we have another case.

24:09

You know, this, this patient, uh, uh, presented

24:12

with bilateral extraocular muscle enlargement.

24:15

You know, just by looking at it,

24:17

it does not look very different from thyroid orbitopathy

24:19

where there is involvement of all the muscles,

24:22

but this patient actually had metastatic carcinoid.

24:26

So, you know, if you, uh, it's important to keep in mind

24:29

that metastatic disease scan involve the orbits.

24:33

Commonly breast cancer, lung cancer tends

24:35

to involve the orbits.

24:36

They can be involvement by, um, GI cancers as well.

24:39

So if you have a patient, if you're dealing with a patient

24:42

who has metastatic disease, um, especially breast, lung,

24:46

or gi, then always, you know,

24:48

think about metastatic disease involving the orbit,

24:50

especially if there is, you know, diffuse involvement,

24:52

especially if there is, uh, you know,

24:54

fat stranding of the orbit.

24:56

Think about, uh, metastatic disease involvement.

24:58

The orbit, although it is much less common compared

25:01

to thyroid orbit, apathy or orbitals tumor,

25:03

or even orbital lymphoma, is much more common than, uh,

25:06

metastatic disease of the orbit.

25:10

So, so far, we talked about preceptor lesions.

25:12

We talked about preceptor, postal cellulitis,

25:15

intracranial complications.

25:16

We talked about intracon lesions, so a lot

25:19

of vascular lesions, uh,

25:20

most commonly cavernous venous malformations,

25:22

common in the intracon, uh, compartment.

25:25

But we also looked at renal lymphatic malformations.

25:27

We looked at lymphomas, orbital pseudotumor,

25:29

then we talked about extraocular muscle enlargement, uh,

25:33

of which they can be many cases,

25:35

most common thyroid orbitopathy,

25:36

they can be orbital pseudo tumor lymphoma,

25:39

and then metastatic disease.

25:41

There can also be sarcoidosis

25:43

that can involve the extraocular muscles.

25:44

Again, bilateral systemic, they can be, you know,

25:47

IgG four related disease can also sometimes involve,

25:51

uh, the extraocular muscles.

25:52

But again, all those things are much less common

25:55

then coming on to extra cornal lesions.

25:58

So lesions that are outside the muscle cone

26:00

and outside the muscle cone.

26:02

A big category of orbital lesions is lesions

26:05

that involve the lacrimal gland.

26:07

So let's talk about lesions

26:08

that involve the lacrimal gland in

26:09

the extra cornal compartment.

26:11

And when we are describing or

26:13

or evaluating lesions of the lacrimal gland, uh,

26:16

the one thing that is important is

26:19

that the lacrimal gland is divided into orbital

26:22

and palpebral portions by this leveta aosis.

26:25

So this is the leveta, a neurosis that is dividing the, uh,

26:29

uh, the lacrimal gland into orbital

26:33

and lacrimal portions.

26:35

So that's number one. There are, you know, certain diseases

26:38

that involve the lacrimal portion,

26:39

and there are certain diseases that involve the, uh,

26:41

orbital portion of the cancer gland,

26:43

especially epithelial lesions.

26:44

So crem adenomas, adenoid cystic carcinomas

26:47

that are the most common, uh, sort of non lymphomas lesions

26:50

that involve lacrimal gland tend

26:52

to be in the orbital portion of the gland.

26:54

Whereas lymphomas tend to involve the gland, um, as a whole,

26:58

uh, that inflammatory lesions, again, tend

27:00

to involve the entire gland, whereas epithelial tumors tend

27:04

to involve just the orbital portion

27:05

of the gland more commonly.

27:07

The other thing that is important when evaluating lacrimal

27:10

gland lesions is whether the lesion is

27:12

unilateral or bilateral.

27:14

There can be bilateral involvement of the lateral gland,

27:17

especially in systemic, uh, diseases, you know, such

27:20

as lymphoma.

27:21

They can be, uh, uh,

27:22

bilateral involvement in sarcoidosis granulomatous diseases

27:26

like granulomatosis of polyangiitis

27:28

or IGT four related disease.

27:30

So these systemic diseases tend

27:32

to involve the lacrimal gland bilaterally, whereas, uh,

27:37

uh, inflammatory lesions, you know, like ditis will,

27:41

will cause unilateral enlargement of the lacrimal plant.

27:43

Or if there are tumors, you know, pulic adenoma,

27:46

Aden cystic carcinoma, even lymphoma, um, tends to, uh,

27:50

tends to be, um, unilateral.

27:52

So, you know, see whether there is involvement of orbital

27:55

or pal proportion.

27:56

And number two C if the involvement is unilateral

27:58

or bilateral.

27:59

So with this information, let's,

28:01

let's look at our first case.

28:03

So here we can see that there is diffuse enlargement,

28:06

diffuse thickening of the right lacrimal gland,

28:08

and along with this diffuse enlargement, that is

28:10

of course, avid enhancement.

28:12

There is a lot of inflammatory soft tissue that is present

28:14

around this diffusely enlarged lacrimal band.

28:17

And this is something that you would see with dro ATUs.

28:20

So ditis or inflammation

28:21

of the lacrimal band will cause this kind of enlargement

28:24

with a lot of inflammatory soft tissue all around it.

28:27

This dro ATUs can simply be, you know, infective, uh,

28:31

but it can also be because of orbital pseudo tumor.

28:34

So if they're presenting with orbital pain

28:36

and such, you know, think about orbital pseudo tumor

28:38

affecting the, uh, affecting the lacrimal gland.

28:42

Then here's, here's another case here.

28:44

We are seeing that there is a focal lesion within the

28:47

lacrimal gland, a focal lesion within the lacrimal gland,

28:50

and it looks like it is involving the orbital portion

28:52

of the gland that the palpebral portion is spared

28:56

and seen anteriorly.

28:58

So this is involving the orbital portion.

29:00

The other thing that is sort of, um, uh, different or,

29:04

or, um, um, um, striking about this particular lesion is

29:08

that it is causing indentation of the G globe.

29:12

Remember we talked about lymphomas,

29:13

and we said that lymphomas tend to infiltrate

29:16

around the structures that come in, uh, come in its way,

29:19

it does not really indent

29:21

or cause mass effect on the structures,

29:23

whereas this lesion is causing indentation of the globe.

29:25

So there are two things here, uh, that, uh, that,

29:29

that are pointing us in a, in a certain direction.

29:31

So when we are evaluating lacrimal gland lesions

29:33

or lacrimal gland masses, the, the two things

29:36

that come first to our mind are,

29:39

is this an epithelial lesion or is this lymphoma?

29:43

So epithelial lesions, as I said,

29:45

involve the orbital portion of the gland more commonly,

29:48

and it looks like this is involving the orbital portion.

29:50

Number two is that lymphomas tend not

29:53

to cause significant mass effect,

29:55

whereas this is causing indentation of the globe.

29:57

So this lesion is more likely to be an epithelial lesion.

30:01

Epithelial lesions of the lacrimal gland, you know,

30:03

more commonly plum morphic adenomas or benign mixed tumors

30:06

or adenoid cystic cancers, plum morphic adenomas tend

30:08

to be a little more common compared

30:10

to adenoid cystic cancers.

30:11

And of course, they have less aggressive features.

30:13

They're, you know, more homogenously enhancing

30:16

do not cause bone erosion.

30:18

And you know, this, this, uh,

30:20

lesion looks like it's following all those characteristics.

30:22

You know, it is higher in signal intensity, it is sort

30:26

of more homogenous and is homogenously enhancing without any

30:30

a cous erosion or, uh, any kind of heterogeneity.

30:34

So this was simply a c clear moic adenoma

30:36

of the lacrimal gland.

30:38

Here we have another case.

30:39

You know, again, there is focal, uh,

30:41

mass within the lacrimal gland,

30:44

and it looks like it is involving, again,

30:46

the orbital portion of the gland.

30:47

The lacrimal portion of the gland, again,

30:49

is seen separately pushed anteriorly.

30:52

This lesion is a little more heterogeneous.

30:55

Uh, this is causing mass effects.

30:57

See, there is a displacement of the superior

30:59

and lateral rectus muscles.

31:01

So again, if we are trying

31:02

to differentiate an adenoid cystic cancer from a lymphoma,

31:05

it looks like this is going to be, uh,

31:07

the features are going more in favor, uh,

31:09

of an adenoid cystic cancer.

31:11

Also, lymphomas tend to cause restricted diffusion

31:14

because of the hyper cellularity.

31:15

And this lesion is not doing that.

31:17

It is not very low in the T two signal,

31:20

which lymphomas tend to be.

31:21

So this lesion turned out to be an adenoid cystic cancer

31:24

and is kind of showing features of an adenoid cystic cancer.

31:29

And then here's another lesion again, that is focal, um,

31:32

enlargement of focal mass within the lac,

31:34

right lacrimal gland, very heterogeneous.

31:37

That is heterogeneous enhancement.

31:38

And this one is causing frank osseous destruction.

31:41

So this was also an adenoid cystic cancer

31:44

of the, uh, lacrimal gland.

31:47

And, and compared this to, you know, these lesions,

31:49

you know, this one is more homogenous.

31:52

That is not significant, uh, displacement of the structures,

31:55

and that is associated restricted diffusion.

31:58

Also, this is a significantly large lesion,

32:01

and you can see that it is conforming to the shape

32:03

of the globe and not really indenting the globe.

32:06

So this kind of features is more consistent

32:08

with the lymphoma, whereas epithelial lesions tend

32:11

to be larger and cause more displacement and,

32:13

and do not, uh, usually have, uh, restricted diffusion.

32:18

Now here's another lesion, again, unilateral involvement

32:21

of the lacrimal gland unilateral, uh, enlargement,

32:24

but the enlargement is very generalized.

32:27

You know, there is involvement of the orbital as well

32:30

as the lacrimal portion of the gland.

32:32

And, uh, and along with that, there is a lot

32:34

of inflammatory soft tissue around that, that focal lesion.

32:38

You know, there is orbital fat stranding,

32:39

there is fat stranding here, there is edema like signal

32:42

and a lot of enhancement.

32:44

And this is, again, one of those lesions

32:45

that is a great mimicker can be commonly, um, uh, sort

32:50

of confused with lymphoma

32:52

because they tend to be in the same locations

32:54

and tend to show some of the common features.

32:56

But this patient presents with orbital pain

32:58

and has a lot of inflammatory soft tissue.

33:00

So this is orbital pseudo tumor

33:02

or idiopathic orbital inflammation.

33:05

And here is a side by side comparison of, uh,

33:09

orbital pseudo tumor and orbital lymphoma.

33:11

These of, you know, these tend to be homogenous,

33:14

but look at all this inflammatory soft tissue

33:16

that is present, uh, around that focal lesion, uh,

33:20

in orbital pseu tumor.

33:21

And these patients commonly present with orbital pain.

33:27

Then coming on to bilateral lateral gland lesions.

33:30

Remember we talked about, uh, you know, lesions

33:32

of the lateral gland that, uh, can be unilateral

33:34

or bilateral, and these are bilateral lesions.

33:37

Uh, these, um, uh, bilateral involvement

33:40

of the lacrimal gland is usually by systemic diseases.

33:44

It could be sarcoidosis, could be IGT four related disease,

33:47

could be grand mitosis with polyangiitis.

33:49

And the unfortunate thing here is that differentiation

33:53

of these diseases, one from the other is,

33:57

um, is less possible.

33:59

So, you know, the, these lesions are commonly confused

34:01

with one another short of a histological diagnosis.

34:04

You, um, um, are less likely to diagnose them on imaging.

34:08

Uh, you know, just by looking at these,

34:10

you can tell which one is which.

34:12

You know, this one was IGT four related disease.

34:15

That one was osis with polyangiitis,

34:17

and this one was, uh, sarcoidosis.

34:19

So on the basis of imaging, it is difficult

34:22

to differentiate, uh, the systemic diseases

34:25

or, you know, bilateral involvement of the lateral clans

34:28

and to complicate things,

34:30

orbital lymphoma can also be bilateral if there is systemic

34:33

lymphoma, non-Hodgkin's lymphoma,

34:34

that can affect lacoma gland bilaterally.

34:37

And although much less common orbital pseudo tumor can

34:41

sometimes also be bilateral.

34:42

So when you have bilateral lac gland enlargement, you know,

34:45

depending on the clinical features, you know, you just have

34:48

to, you know, give you a differential diagnosis

34:50

that there is bilateral lateral gland enlargement.

34:53

It could be because of, you know, sarcoid,

34:55

oma disease lymphoma or, uh, or pseudo tumor.

34:58

If you have orbital pain, then um, pseudo tumor, uh,

35:02

tends to be favored.

35:03

Uh, but again, there is, there is no way to know.

35:07

Alright, so we talked about, you know, we are,

35:09

we are still in the realm

35:10

of talking about extra cornal lesions, uh,

35:13

in extra cornal lesions.

35:14

The biggest category is, uh, the lacrimal gland lesions,

35:17

but there are other lesions that can be, uh, extra cornal

35:20

and um, as well, uh, so this patient who presented

35:22

with right forehead numbness, we are seeing

35:25

that there is a well-defined sort of, uh,

35:28

hypodense lesion in the superior orbit

35:31

that extends from the posterior orbit to,

35:34

to the anterior orbit sort of, uh, tubular.

35:37

And with this kind of history, uh, if, if you, uh, sort

35:41

of correlate the history with, with the finding this kind

35:43

of tubular enlargement, we know that the V one segment

35:47

of the trigeminal nerve travels along the orbital roof,

35:51

and of course, V one, uh, is responsible for sensory, uh,

35:56

distribution at the forehead.

35:57

So with this kind of history, you know, we can, we can come

36:00

to the conclusion that this is probably a V one schwannoma,

36:02

which is what it turned out to be.

36:05

Uh, so this is, uh, again, showing an extra corona lesion

36:07

that that can be there in the, uh, superior orbit.

36:11

Then V one schwannomas or sonomas of the, uh, of V one

36:15

and V two are less common.

36:17

More commonly, what you will see in the head

36:19

and neck region, especially if the patient has head

36:22

and neck cancer, is very neural tumor spread.

36:24

So this patient had history of head and neck cancer,

36:26

and what we are seeing is that that is thickening of the,

36:29

of the V one segment of, uh, the nerve

36:31

that is also some soft tissue at the supraorbital nerve,

36:35

uh, uh, portion.

36:36

Again, on these coronal images, we can see

36:38

that there is thickening all along the V segment of, uh,

36:41

the trigeminal nerve.

36:43

Not only that, there is some inflammatory soft tissue at the

36:45

orbital apex, and this one is also extending all the way

36:49

to the V two segment of the trigeminal nerve.

36:52

So this is a perineal tumor spread along the V one

36:55

and V two segments of the trigeminal nerve in a patient

36:58

who has known head and neck cancer.

37:00

So always keep that in mind

37:01

because, um, you know, you might see an orbital mass, which,

37:06

uh, is simply just perineal tumor spread from,

37:08

from an adjacent cancer.

37:10

Um, adenoid cystic cancer actually can do that as well

37:12

because adenoid cystic cancers are lesions that

37:16

have a higher propensity for perennial tumor spread.

37:19

So a lacrimal gland adenoid cystic cancer can also cause,

37:23

uh, perennial tumor spread along the, uh,

37:25

different nerves of the orbit.

37:28

Then another extra cornal lesion here.

37:31

Here we are seeing a fat density lesion in the

37:33

superior lateral orbit.

37:35

Um, and just by the fat density you can deduce

37:38

that this is an orbital dermoid.

37:40

They can be fat or fluid density.

37:42

Of course, if you see fat, you're lucky, you can diagnose,

37:45

uh, an orbital dermoid there in this, you know,

37:47

typical location adjacent to the, uh, orbital sutures.

37:53

Then before I go on to, uh, lesions of the globe

37:56

and the, uh, optic nerve sheath complex,

38:01

I wanted to talk a little bit about

38:03

diffusely infiltrative lesions.

38:05

You know, we, we, so far, we talked about, you know,

38:08

focal lesions, cous malformations, you know, lymphomas

38:12

or, uh, lesions involving the lacrimal clan,

38:14

but there are certain lesions

38:15

that can diffusely involve the orbit.

38:17

Again, you know, pseudo tumor tends to be everywhere.

38:20

So pseudo tumors can be, they can be diffused variety

38:22

of orbital pseudo tumor or idiopathic oric inflammation

38:25

where there is involvement of all the extraocular muscles

38:28

that is involvement of the orbital fat lact from or gland.

38:31

Um, and in this particular case, actually,

38:33

this is going all the way to the orbital apex

38:37

and also involving the, the cavernous sinus.

38:40

And when this involves the, the nerves

38:42

and the lateral wall of the cavernous sinus,

38:44

it produces atypical clinical syndrome known as OSA hunt.

38:48

Terosa hunt is painful of thal plegia

38:50

because in involvement of nerves at the lateral wall, uh,

38:54

of the cous sinus, I'm showing you this case

38:57

of diffuse orbital pseu tumor leading to terosa hunt.

39:00

Uh, you should not take away from this,

39:02

that only the diffuse variety

39:04

of orbital pseu tumor can cause to Osa hunt.

39:07

They can only be a small lesion at the orbital apex

39:10

that can cause hun, this, you know,

39:12

this particular case just happens to be a case

39:14

of diffused pseudo tumor, which is causing to lose a hand,

39:16

but to lose hand can be present with even smaller lesions

39:19

and a non diffused variety of orbital pseudo tumor as well.

39:22

But yeah, when you have that, um, clinical syndrome

39:25

of painful of thal plegia,

39:27

and you see a lesion within the orbital apex that extends

39:31

to the cab sinus of the lateral wall, think about, uh,

39:33

orbital tumor and osa hunt.

39:36

And then of course, the second lesion

39:38

that it diffusely involves the orbit is orbital lymphoma.

39:41

They can be, uh, you know,

39:43

generalized involvement in lymphomas as well.

39:45

They, they, uh, can involve all the structures,

39:49

but even in this, you can see that

39:51

although there is diffuse involvement of the orbit,

39:54

these lymphoma lesions are not significantly displacing the

39:58

orbital structures, which tends to be what lymphomas do.

40:01

They just tend to infiltrate

40:02

and conform to the shape of all the,

40:04

all the structures that come in their way.

40:06

So, you know, when you're dealing with orbital lesions,

40:09

think about a lymphoma is something that is, you know, sort

40:11

of just going around these lesions

40:13

and not causing significant displacement.

40:16

Then other lesions, of course, cellulitis.

40:18

We already saw this case where there's, uh,

40:20

there was involvement of the cavernous sinuses, um,

40:23

causing orbital compartment syndrome.

40:25

Uh, plexiform, uh, neurofibromas in the setting of type two,

40:29

uh, type one, excuse me, neurofibromatosis can cause uh,

40:33

diffuse involvement

40:34

and then of course, metastatic disease, whereas

40:37

where breast cancer, lung cancer, uh,

40:39

and carcinoids are common.

40:41

Uh, one thing to keep in mind for, uh,

40:43

breast cancers infiltrating

40:44

or involving the orbit is that, uh, the scar kind

40:48

of breast cancer can involve the orbits,

40:51

and in that case, the clinical picture is not of proptosis,

40:54

but of an ophthalm.

40:56

So there is some kind of fibrotic

40:57

or desmoplastic reaction that is seen with skin cancers of,

41:02

uh, the breast, which metastasize to the orbit.

41:04

So you will see diffuse involvement of the orbit,

41:07

and instead of proptosis there would be an ophthalm.

41:10

So something to keep in mind when evaluating orbit for, uh,

41:14

breast metastasis.

41:17

Then coming on to optic nerve sheath complex lesions.

41:22

So here's, here's our first case

41:24

and, and what do we see here?

41:25

So we are seeing that there is a, a lesion in the region

41:28

of the optic nerve that is, you know, a well-defined, uh,

41:31

thickening, so to speak, of the optic nerve itself.

41:35

Um, uh, it, it that is associated heterogeneous enhancement.

41:38

And what is seen in this case is

41:40

that there is diffuse thickening of the nerve itself

41:43

and you cannot see the nerve separately.

41:45

And this kind of picture where there is diffuse thickening

41:47

of the nerve itself with enhancement

41:50

where the nerve cannot be differentiated from the mass

41:52

itself, especially if these

41:54

patients have type one neurofibromatosis is seen

41:57

with optic nerve glioma.

41:58

Of course, they can be sporadic optic nerve gliomas not

42:01

associated with NF one,

42:03

but if the patients have NF one, uh, it tends

42:05

to be more count in those cases, it tends to be bilateral

42:08

and can involve the optic chiasm as well.

42:11

Now this imaging picture is very distinct from this

42:14

particular mass, which is around the optic nerve,

42:17

and you can see the nerve separately from the mass itself.

42:21

So you can see that there is this mass that is

42:23

around the optic nerve, but you can still see the

42:26

central optic nerve.

42:27

It is all around the optic nerve.

42:28

And this kind of imaging picture that

42:30

where there is an enhancing mass around the optic nerve

42:34

or involving the optic nerve sheath is seen

42:36

with optic nerve sheath meningiomas.

42:39

Another case of optic nerve sheath meningioma

42:41

that is circumferential thickening all

42:44

around the optic nerve,

42:45

but you can still see that there is some semblance

42:48

of the nerve itself in the, uh, in the center

42:51

of this enhancing lesion.

42:53

When these lesions are longstanding, they can calcify

42:56

and can present with this typical

42:58

t tram track calcification around the nerve.

43:02

Then, uh, there can be other lesions that can involve, uh,

43:05

the optic nerve, uh, itself.

43:07

This is a patient who presented a young patient

43:10

that presented with acute left-sided vision loss.

43:13

And what we are seeing is that there is some optic, uh,

43:16

disc edema and there is enhancement of the optic nerve head.

43:20

And this kind of bright spot central sign has been described

43:23

with giant cell arthritis.

43:26

They can be anterior ischemic optic neuropathy,

43:29

which can be arthritis

43:30

or non-A in young patients,

43:32

what you see commonly is the arthritis type of, uh, of, uh,

43:37

anterior ischemic optic neuropathy,

43:38

whereas an older patient's non-A

43:40

because of diabetes, hypertension, what have you.

43:42

Uh, but when you have a young patient presenting with, uh,

43:46

acute vision loss and you see this kind of picture,

43:49

think about arthritis, anterior ischemic optic neuropathy,

43:52

uh, usually in the setting of giant cell arthritis.

43:56

Then besides this, uh,

43:58

demyelinating diseases can affect the optic nerve

44:01

as we all know, and there are several kinds

44:04

of dem marinating diseases that can affect the optic nerve,

44:06

you know, multiple sclerosis being the most common,

44:09

but then there are other kind of optic nerve, uh, um,

44:11

other kind of dem marinating diseases

44:12

that can affect the optic nerve.

44:14

Um, and a most spectrum disorder is a big one.

44:17

We all know about that a newly described entities MA

44:20

or myelin oligo, uh,

44:21

oligodendrocyte associated de marinating disease.

44:24

And this was a wonderful article.

44:25

I took this image from this article,

44:27

which beautifully describes the, uh,

44:29

different differentiating features

44:31

of optic nerve involvement

44:33

or brain involvement in in these three entities.

44:35

I highly recommend reading this article.

44:37

So what they describe is that in moga there is, you know,

44:40

long segment diffuse involvement of the anterior portion

44:43

of the optic nerve usually tends to be bilateral,

44:45

and there is a lot of per neuritis associated with MOA.

44:49

Whereas in NMO spectrum disorder,

44:51

there is usually posterior nerve involvement with, uh,

44:54

with frequent involvement of the optic chiasm.

44:57

Whereas in multiple sclerosis,

44:59

there is short segment involvement

45:01

and uh, which could be unilateral sometimes could be

45:03

bilateral, but there is short segment anterior nerve

45:06

involvement in, uh, multiple sclerosis.

45:10

Finally, talking about, uh, lesions of the globe, um,

45:15

I'm nearing the end of my talk.

45:17

Um, so, uh, different kind of hemorrhages

45:20

that can be present within the globe uh, com.

45:23

Two common detachments, retinal detachment

45:25

and choroidal detachment.

45:27

Uh, the typical pattern

45:28

of retinal detachment is this reshaped detachment where, uh,

45:33

there is tethering to the optic nerve head posteriorly,

45:36

and the common pattern of choroidal detachment is this bi

45:38

convex shape, and if it's bilateral, there tends

45:41

to be these, uh, kissing choroidal detachment.

45:43

So this is, uh, sort of the two common attachments

45:46

that you might see in the globe.

45:50

Then here we have a focal lesion in the globe.

45:53

It looks like a mass, uh,

45:55

within the globe it is hyperintense on, uh,

45:59

T one weighted images, sort

46:00

of high point intense on T two weighted images

46:02

and is showing avid post contrast enhancement.

46:05

The most common adult globe malignancy

46:09

that you will see is a UVL melanoma,

46:11

and this is the typical appearance of a UVL melanoma

46:14

where it is hyperintense on T one

46:16

because of the paramagnetic effects of melanin, uh, tends

46:19

to be hyperintense on T two N shows homogenous enhancement.

46:22

Can this be something else?

46:24

Uh, potentially it could be choroidal metastasis, uh,

46:27

but the T one hyperintensity would be lacking in a

46:30

choroidal metastasis.

46:31

Um, could it be focal, um, you know,

46:33

hemorrhage within the choroid?

46:35

I guess it could be, but it is very focal.

46:37

Usually, you know, hemorrhages tend to be more diffused.

46:39

Uh, so this, this kind of focal lesion, especially in adult,

46:42

should always raise the possibility

46:44

of a uveal melanoma most more commonly seen in choroid.

46:47

So choroidal melanoma, um,

46:50

and Mr is, is really, really helpful in the evaluation

46:54

of uveal melanomas or choroidal melanomas

46:56

because you can, uh,

46:57

because you can comment on extraocular extension, which is,

47:01

uh, better seen on Mr.

47:02

Uh, and then you can also differentiate the hemorrhages, uh,

47:06

that tend to be common with uveal melanomas from actual ma.

47:09

So, you know, enhancing nodules can be differentiated from,

47:12

uh, from the hemorrhage itself, uh, on mr.

47:17

Then, um, you know, what else can look like uveal melanoma,

47:20

choroidal metastasis, as I talked about, you know,

47:23

from breast and um,

47:24

and lung, uh, can cause um, metastatic involvement

47:29

of the choroid itself in kids retinoblastoma is a big one,

47:32

you know, tends to be bilateral trilateral sometimes, uh,

47:35

and then of course they can be benign choroidal osteo

47:38

that causes this, uh, calcification

47:40

or dystrophic calcification of the, uh, of the globe.

47:44

Then finally, some, some other diseases of the globe

47:47

that we see commonly.

47:48

Uh, we commonly see scleral plaques

47:51

or, um, uh, scleral calcifications in older population.

47:54

We can see optic nerve head drusen,

47:56

which is the spectate calcification at the optic nerve head

48:00

thesis bulb by which is sort of an end stage globe,

48:03

which could be resolved of trauma or inflammation.

48:07

Uh, some kind of s scleritis.

48:09

Uh, then glaucoma devices are commonly seen, you know, not

48:12

to be confused with some kind of pathology, um,

48:15

anti posterior elongation

48:17

of the globe seen in axial myopia when there is, you know,

48:20

focal ectasia of the globe due to weakening of the sclera

48:24

that is sta they can be focal deficiency

48:27

of the globe itself, which is seen in Cobos.

48:29

Usually these are so also associated with, um,

48:34

with mith thalamus

48:35

and optic nerve head is also a common location for Cobos.

48:39

Uh, and then finally you can have this dense intraocular

48:42

silicone, uh, that is placed in the, uh, in the globe

48:46

after treatment of, uh, retinal detachment.

48:52

Then finally, uh, you know, I wanna say

48:54

that most orbital lesions are compartments

48:56

specific as we saw.

48:57

Uh, you know, there is a, a set set of differentials

49:00

that you think about when you think

49:01

about different compartments.

49:03

Uh, but lymphomas and orbital psal tumor are great mimics

49:06

and can be present anywhere in the orbit.

49:09

Uh, clinical symptoms are important.

49:10

You know, psal tumor is usually going to present with pain.

49:13

Uh, so think about that, uh,

49:15

and the clinical course is usually, uh,

49:17

important when we are, uh, making a differential with this.

49:21

I wanna thank you all for a patient hearing.

49:24

I'm gonna stop sharing my presentation

49:26

and I welcome any questions at this time.

49:30

Yeah, thank you so much for your lecture, Dr. Agarwal.

49:32

And yes, at this time we will open the floor

49:34

for any questions from the audience,

49:36

and you may submit your questions

49:37

through the q and a feature.

49:40

It looks like we have a couple in there already, Dr.

49:42

Agarwal, if you're able to pull those up.

49:44

Yeah, so any good imaging signs of glaucoma.

49:47

Um, not that I know. I think glaucoma is sort

49:49

of a clinical diagnosis that is based on measuring of the,

49:52

um, ocular pressure.

49:54

So, um, I don't know of any good imaging signs for glaucoma.

49:58

Uh, glaucoma devices are pretty much MR.

50:00

Compatible, all the newer glaucoma devices,

50:02

you see them all the time, uh, on mr.

50:05

So yeah, they're, they're pretty much Mr. Compatible.

50:07

Can you tell us what protocol you perform for the orbit?

50:10

Uh, so we do, uh, pretty much, uh, six sequences.

50:15

Uh, we do coronal and axial, so coronal

50:20

and axial store images, and then coronal and axial pre

50:24

and post contrast, uh, T one weighted images

50:26

where the pre contrast imaging is non-fat suppressed

50:29

and the post contrast images are fat suppressed.

50:31

So that is the protocol that we use for, um,

50:35

uh, for our orbit.

50:37

Which nerve route?

50:39

The speral spread of adenoid cystic car used usually.

50:42

So, um, usually it's the, um, it's the, uh,

50:45

the V one segments, um, in the orbit,

50:48

but you know, pretty much it depends on where, uh,

50:50

the lesion is and it can hop onto, um, any of the nerves.

50:54

Uh, but commonly the V one segment is involved,

50:56

they can be posterior, uh, extension into the orbital apex,

50:59

and at that time it can involve other nerves as well.

51:02

How frequently do you see foreign body injuries to the eye,

51:05

and what are the common types of injury?

51:08

Um, yeah, I mean, trauma is pretty common.

51:10

It can be any foreign body, especially in, in, uh,

51:13

people who work with metal.

51:15

There are a lot of met metallic foreign bodies,

51:17

but it could practically be anything.

51:19

Uh, orbital trauma itself is a whole topic in itself, uh,

51:23

where there can be, you know, orbital fractures,

51:25

there can be globe, uh, rupture,

51:27

there can be lens dislocation

51:29

and different kinds of hemorrhages.

51:31

Um, so yeah, that's, uh, that's different.

51:39

Oh, my friend Lorenzo is here.

51:41

Um, that's, that's, that's great. I'm, I'm humble.

51:44

He's asking great lecture. Thank you for sh uh,

51:46

do you use EPI non E-P-I-D-W-I for the orbits?

51:50

So, uh, we generally just use EPI for,

51:54

um, for temporal bone.

51:56

We tend to use non EPI sequences, uh,

51:58

but for orbit, we, uh, don't employ the, uh,

52:02

non E-P-I-D-W-I for, for specifically for orbits.

52:09

So, um, could you please explain the air inside the vase?

52:13

Again, it was simply because of venipuncture.

52:15

You know, when you put, uh, you know, venous cannula

52:19

that can introduce air

52:20

and that can, it commonly appears in cab sinuses can also

52:23

appear in orbital veins, and sometimes it's more extensive.

52:29

Myop and staph diagnosis are just descriptive terms.

52:32

And should we recommend ophthalmology consult,

52:35

they usually do not require a dedicated consult.

52:37

Uh, when I see them, I usually talk about them, um,

52:40

you know, axial myopia

52:42

and staph in cases

52:45

of complicated sinusitis and orbital abscess.

52:48

Do you prefer drain

52:52

endonasal or medial anthology?

52:55

I don't know.

52:57

I, I don't think I'm an expert enough to talk about, um,

53:00

what kind of drain we use.

53:02

We, we don't do orbital procedures, so I'm sorry,

53:04

I can't answer that for you.

53:06

Some say TLO hunt is a diagnosis of exclusion. Do you agree?

53:10

Uh, well, TLO hunt is a, is a clinical syndrome, uh,

53:14

and when you see specific features

53:15

that could explain those symptoms, you, you tend

53:17

to, uh, talk about that.

53:19

Uh, you know, I would not say in my impression

53:21

that findings are suggestive of tho Hans syndrome

53:23

because again, it's a, a clinical diagnosis

53:26

or at least based on, uh, clinical features.

53:28

But when, uh, the request comes with painful of plegia

53:32

and if I see signs where it can be explained

53:35

by the imaging features, I would, I would talk about that.

53:39

Is it possible to differentiate inflammatory pseu tumor

53:41

involving lateral plan and ditis on imaging?

53:44

No, you can't. Uh, what about choroidal angio,

53:49

how you do differentiate it from melanoma

53:51

when the lesion is small?

53:53

You know, when the lesions are small and,

53:55

and hemorrhagic, uh, it's, uh, it's difficult.

53:58

Uh, but I would tell you that choroidal melanomas are far

54:01

more common than choroidal angios.

54:03

So if I see, uh, a lesion in the globe

54:07

that is T one hyperintense is enhancing associated

54:10

with retinal detachment

54:11

and hemorrhage, I would think, uh, more about UVL melanoma

54:15

or choroidal melanoma than angio.

54:20

Can you please repeat the differences

54:21

between thyroid and pseudo tumor?

54:23

Uh, thyroid tends to be bilateral, uh, tends

54:27

to spare myo tenderness.

54:28

Junctions, uh, has a set pattern of involvement.

54:32

Um, you know, I am slow.

54:34

So those are some of the differences.

54:36

Can we see OSA hunting in kids?

54:38

I imagine we can, I don't practice beads that much, so

54:43

I max you can endon or medial canmy.

54:47

I, I don't know. Uh, intriguing case here, we have a patient

54:51

with parasitic worm.

55:00

I don't know if I get this question.

55:01

Patient felt movement around orbital region suspected

55:04

to be there to above the eyeball

55:07

worm body could be suppressed,

55:08

and that could affect visibility,

55:11

this unique case successfully.

55:14

I don't know, I've, I don't have any personal, um,

55:17

experience with imaging worms in the orbit by imagine,

55:20

but I imagine, uh, if you're suspecting it in the globe

55:24

or the orbit, you could potentially, um,

55:30

use, uh, b scan

55:32

or ultrasound, you know, that might be, uh, a,

55:35

you might be able to visualize some of it, but I don't know.

55:38

I have, uh, I, I don't have experience with that.

55:45

Yes, is close a hundred extension. Yes, that is what it is.

55:52

All right. I think I answered all the questions here.

55:55

Yeah. Excellent job, Dr. Aggarwal.

55:58

Thank you so much for like rapid fire answering the,

56:00

all those questions that came in.

56:04

And thanks to everyone

56:05

for participating in our noon conference

56:07

and asking great questions.

56:09

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56:11

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56:13

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56:15

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56:19

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56:22

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56:24

Catherine McGillan will deliver a lecture entitled Acute

56:27

Abdominal Imaging.

56:29

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56:31

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56:33

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56:35

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56:37

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