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Hello and welcome to Noon Conference hosted by MRI Online

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Today we are honored to welcome back

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to the noon conference stage Dr.

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CSH McCury for a lectured entitled Post-Treatment Imaging in

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the head and neck, how

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to distinguish expected changes from

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treatment complications.

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Dr. McCury received his undergraduate degree from Duke

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University and his MD degree from Georgetown University.

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He currently holds appointments at multiple institutions

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and is a devoted educator

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who has been an invited speaker on over 500 occasions

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and has also written and edited 15 textbooks.

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He's a consulting editor for both neuroimaging clinics

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and Magnetic Resonance Clinics of North America

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and Associate editor for the Journal

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of Computer Assisted Tomography.

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At the end of the lecture, please join him in a q

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and a session where he will address questions you

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may have on today's topic.

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Please remember to use that q

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

1:10

as many as we can before time is up.

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

1:16

McCury, please take it from here.

1:19

Okay, great. Okay. Alright, well thanks

1:21

for um, again, having me here.

1:22

It's a real, uh, honor and privilege to to be here.

1:26

And uh, today what we're gonna do,

1:28

and we're really doing this talk based on the feedback

1:31

that we've had on some of the last sessions, is

1:33

that we're specifically gonna give a talk on post-treatment

1:36

changes and complications, um, in patients with head, head

1:41

and neck cancers that have been treated.

1:43

And we're really gonna focus on how

1:45

to distinguish recurrence from complications.

1:49

And the one thing that I wanna say upfront is

1:51

that we're not gonna be talking about pet imaging in the

1:53

head and neck because that really is its own separate talk.

1:57

So what I want to do is really focus on the

1:59

cross-sectional imaging.

2:01

Um, and then what I'll do is, you know,

2:03

obviously interject when it would be appropriate

2:06

to get PET imaging,

2:07

but we're really gonna concentrate on just the

2:09

cross-sectional imaging.

2:11

So when we talk about patients with head

2:15

and neck cancers, you know, we have a primary tumor

2:18

and then there are different ways

2:20

that these patients can be treated

2:22

and one of the ways can be with some type

2:25

of non-surgical organ preservation therapy.

2:28

And in this day and age it's typically chemotherapy

2:31

and radiation therapy.

2:33

And occasionally you can have immunotherapy as well too.

2:37

The other primary option is surgery.

2:39

So as we all know, chemoradiation is primarily,

2:42

or I should say preferred in patients

2:45

with HPV carcinomas involved in the oral pharynx.

2:48

And surgery is typically preferred for those patients

2:51

that are non HPV squamous cell carcinomas.

2:55

So what we'll first do is talk about chemotherapy

2:59

and radiation therapy.

3:01

So we'll first discuss expected changes

3:04

and it's essential

3:06

that when you are looking at something like this,

3:09

'cause this is a relatively complex topic, is

3:11

that when we start talking about the post-treatment changes,

3:15

it's really important

3:16

that you get the pre-treatment studies.

3:19

So you're gonna see this need pre-treatment studies

3:22

because in order to understand following treatment changes,

3:26

it really is helpful to know what you have before treatment.

3:31

So when patients have radiation therapy,

3:35

it is important to understand the histology.

3:38

Now you don't have to understand every bit

3:40

and piece of the histology,

3:42

but the points that I want to make is are the following is

3:45

that within 24 hours

3:47

after given radiation therapy,

3:49

you have this acute inflammatory response

3:52

and then it's followed by interstitial edema.

3:56

Now this interstitial edema eventually goes on to fibrosis

4:01

and the fact that there's this interstitial edema

4:04

and then you have fibrosis.

4:05

Really this is the underlying factor that contributes

4:09

to the imaging changes

4:11

that you'll see following radiation therapy.

4:15

Now oftentimes now in 2024, the patients are also treated

4:18

with chemotherapy as well too.

4:20

There are not any real specific changes

4:23

that are associated with chemotherapy.

4:26

But on the other hand, this does exacerbate the changes

4:29

after radiation therapy.

4:32

So here's some examples

4:33

of a patient pre-treatment and post-treatment.

4:36

So this is pre-treatment

4:38

and I wanna point out just the appearance of the epiglottis.

4:41

I wanna point out the appearance here of the platysma muscle

4:44

and the subcutaneous tissues.

4:47

So this is pretreatment, this is

4:49

what happens post-treatment.

4:51

So when you first look at this,

4:53

this can kind of catch your eye.

4:54

This is not abnormal, this is just normal.

4:57

And this is just edema involving the supra hyoid epiglottis.

5:02

So this is that edema from the radiation therapy.

5:05

And also note, it's how it's symmetric.

5:07

It's a relatively symmetric appearance.

5:10

Similarly after hum radiation therapy,

5:13

this is again edema involving the pre ELO space.

5:17

I also wanna turn your attention to the plAsa muscle.

5:19

Notice the thickening of the plAsa muscle.

5:22

This is all in normal expected change.

5:24

If you look just above this, this is all reticulation

5:28

of the subcutaneous tissues.

5:30

And then occasionally you can see that skin thickening.

5:33

You know, I see patients once a week

5:35

and I see these post-treatment changes.

5:37

So the skin thickening is much easier to see

5:40

when you actually see the patient alive

5:42

and sometimes is a little bit harder

5:43

to see on cross-sectional imaging.

5:45

The other uh, expected change that I want you

5:48

to be appreciative of is look at the normal appearance

5:52

of the submandibular glands pretreatment

5:55

and then following treatment, notice how they're thickened

5:58

and they're enhancing

5:59

and they're actually a little bit shrunken here.

6:02

So this is what we refer to as radiation s adenitis.

6:06

So this diffuse thickening of the epiglottis, this edema,

6:10

this radiation s adenitis, the thickening

6:12

of the platysma muscle, these are all expected changes

6:16

after radiation in chemotherapy.

6:20

So those are the expected changes.

6:22

Now the other thing that we have to be aware of is whether

6:26

or not those patients that have tumors

6:30

actually have a response to some type

6:32

of non-surgical organ preservation therapy.

6:35

So this is an example of a patient that has a tumor

6:38

that's involving the ula.

6:41

So the normal anatomy here is that this is our epiglottis.

6:45

This is what we refer to

6:47

as the median gloss epiglottic fold.

6:49

And in this pretreatment study we can see this tumor right

6:53

here involving the molecular.

6:55

Now after treatment look, notice what we see right now.

6:58

Notice how this free margin,

7:00

the epiglottis has become thicker, it has a low attenuation

7:04

and that's due to the edema.

7:06

And now all of a sudden we're seeing this little fold

7:10

that goes from the tongue base to the epiglottis

7:13

and what do you call that fold

7:15

that goes from the tongue base to the epiglottis.

7:18

Well that's the median glosso glosso is Greek for Latin

7:23

epiglottic fold.

7:24

And now you can see this thing magically appear

7:27

because the tumor right here has had a complete response.

7:32

The other thing too is look at the subandi glands.

7:34

Look at the subandi glands.

7:36

This is that radiation sil adenitis that we talked at,

7:39

that we mentioned before.

7:41

So what we have here is a complete local response

7:45

and we can see this tumor's completely evaporated,

7:48

if you will, after the chemotherapy

7:50

and the radiation therapy.

7:53

Now let's contrast that appearance with this appearance.

7:57

So this is a patient that has a tumor involving

8:01

the epiglottis.

8:02

So this is our epiglottis here.

8:03

This is actually extending into the pre epiglottic space.

8:07

So this is pre-treatment

8:10

and following treatment, look right here.

8:12

Notice how there's still this persistent mass right here

8:16

that's extending into the pre epiglottic space.

8:19

So that is not complete resolution, rather

8:22

that's a persistent mass.

8:24

And this is what is suggestive of non-responding

8:27

or if you will, recurrent tumor

8:30

involving the pre epiglottic space.

8:33

So, so far, just to kind of recap where we've come,

8:36

what we first talked about was the expected changes

8:39

and we talked about the diffuse thickening and the edema.

8:43

This is due to the radiation therapy

8:45

resulting in that edema.

8:47

Then the next thing that we talked about

8:50

was a complete local response.

8:52

So this is pre-treatment and this is post-treatment.

8:55

And now we're starting to see this normal anatomy appear.

8:59

And now we showed an example here of a non-responding tumor

9:03

and this is what we see when we look for recurrent disease.

9:07

So now let's talk a little bit about some

9:10

of these complications.

9:12

So one of the biggest challenges that we end up seeing is

9:15

that yeah, we can see recurrences,

9:17

sometimes we see complete response,

9:20

but oftentimes we're left

9:22

with this confusing appearance on cross sexual imaging.

9:26

And we're trying to figure out is that a complication?

9:28

Is a recurrence, is it non recurrence?

9:30

You know, when should we suggest getting PET cts in specific

9:35

uh, situations?

9:36

And that's what we wanna discuss right now.

9:40

So one of the first complications that we run into is

9:44

what we refer to as laryngeal or con necrosis.

9:48

So what this is is a rare complication

9:51

following radiation therapy.

9:53

Now I remember this

9:54

because back when I was a fellow, all of a sudden

9:58

before the 1980s or so, the majority of head

10:01

and neck cancers were being treated with surgery.

10:04

But then what happened is

10:05

that some very smart people realize that hey,

10:08

we can treat head

10:09

and neck squamous cell carcinomas with radiation therapy.

10:14

So after about the mid eighties

10:16

or so, we started seeing some of these uh, complications.

10:21

Now granted they are rare,

10:23

but that's when they sort of first came to light.

10:25

So when we talk about laryngeal

10:27

or con necrosis,

10:29

this is a rare complication following radiation therapy.

10:33

It's typically seen 12 months

10:35

after the completion of radiation therapy

10:38

and the dose is higher.

10:39

It's typically associated without seven by 7,000 rads.

10:44

And when you have concurrent chemotherapy,

10:47

this increases the likelihood of con necrosis.

10:51

So this is an example

10:53

of a patient has a squamous cell carcinoma involving the

10:56

left area epiglottic fold pre-treatment.

10:59

And this is what we see post-treatment Notice we can see

11:02

this kind of floppy low attenuation involving the left

11:06

area epiglottic fold.

11:08

And we can see this area of low attenuation that's sort

11:11

of ulcerated and extending into the area epiglottic fold.

11:16

Now the bottom line is, is

11:18

that we cannot completely, excuse me about that.

11:21

We cannot completely exclude the possibility of tumor.

11:24

There could be microscopic disease here.

11:27

But on the other hand, when I see this, what I begin

11:31

to ask myself is number one, first of all,

11:36

when was the radiation therapy completed?

11:38

Because if the radiation therapy was just completed, well

11:43

that's not the typical time

11:44

that we'd see radiation necrosis.

11:46

So I wanna see radiation necrosis

11:49

after 12 months after completion.

11:52

Also, if someone told me, Hey, the dose

11:54

that was given was only 3000

11:56

or 4,000, then I'm more apt to call this tumor.

12:00

But on the other hand, in order

12:02

to be a very accurate radiologist

12:04

and be as um, likely that we're gonna come to

12:07

that right diagnosis, we have

12:09

to take into consideration the dose and the time

12:13

after completion of radiation therapy.

12:17

So excuse me, this is the typical appearance that we'd see

12:20

with laryngeal oron necrosis.

12:23

Now there are certain more specific findings

12:26

that will tell us that we're dealing

12:27

with laryngeal oron necrosis.

12:30

Number one is the presence of air in the soft tissues.

12:34

If we have a patient that's been treated with chemotherapy

12:37

and radiation therapy, they have been treated

12:40

with high dose radiation therapy and we're after 12 months

12:43

after completion

12:45

and now all of a sudden I start

12:47

to see air in the soft tissues.

12:49

The first thing I have to ask myself,

12:52

does the patient have any injury?

12:54

Because it's possible if the patient had some type of trauma

12:58

that caused a fistula from the larynx into the soft tissue

13:01

that could be due to the air.

13:03

The other thing is I want

13:04

to make sure the patient is in febrile

13:06

because if the patient's febrile anytime

13:09

that we see gas in the soft tissues, we have

13:12

to start thinking about things such

13:14

as necrotizing fasciitis.

13:16

But in the absence of fever, in the absence of any trauma,

13:20

so on and so forth,

13:22

this air in the soft tissue is a pretty high indicator

13:26

that we're dealing with laryngeal oron necrosis.

13:30

And part of the reason we get that air is

13:32

because you could have gas formation in the um,

13:36

the cartilages and that nitrogen can kind

13:39

of seep out into the soft tissue.

13:41

So that's why we end up getting

13:42

that air in the soft tissues.

13:46

Another finding that is uh, consistent with laryngeal

13:50

or con necrosis is sometimes you can actually have

13:53

dislocation of the cartilages.

13:55

So this is pre-treatment

13:57

and post-treatment, if we start seeing this dislocation

14:00

of the cartilage, that again is another sign

14:03

that we have underlying laryngeal, uh, or con necrosis.

14:08

And if this gets really severe, this laryngeal

14:11

or con necrosis, you can have internal fistula formations.

14:15

And this is an example of fistula formation

14:18

that extended from the larynx into the retro

14:20

pharyngeal space.

14:22

And unfortunately this patient ended up developing a retro

14:25

feral space abscess

14:27

and this was due to

14:28

that direct fistulization from the airway extending into the

14:32

retro feral space.

14:34

So this was an example

14:35

of laryngeal andon necrosis plus an infection.

14:40

Now the next thing that we'll talk about again is a

14:43

complication of radiation therapy.

14:46

But instead of necessarily really focusing on the soft

14:50

tissues, this is really focusing on the bone.

14:53

And this is why we call it osteo radionecrosis.

14:56

So if we went back, we call this laryngeal

14:59

or chondro necrosis.

15:01

Now we're gonna talk about osteo radionecrosis.

15:05

And again, osteo radionecrosis was described

15:07

around in the 1980s

15:09

because that's when we first figured out

15:12

that radiation therapy can be definitively cure certain

15:16

types of squamous cell carcinoma.

15:19

Again, it's associated with a higher dose,

15:22

typically greater than 6,000 rats.

15:25

And the characteristic findings are the presence

15:28

of on CT cortical interruption sequestration

15:32

and pathologic fractures.

15:34

So this is an example

15:35

of osteo radionecrosis involving the right

15:38

side of the mandible.

15:40

What we see here is cortical disruption

15:42

and we can see this fragmentation

15:44

of the bone involving the mandible.

15:47

And then when we look on the CT scan here,

15:50

we can see the disruption,

15:51

we can see the pathologic fracture of the bone.

15:54

And you can also see this increased soft tissue thickening

15:58

involving the masticator space.

16:00

Now when we see something like this, there's no way

16:03

that we can exclude microscopic tumor.

16:06

It's just impossible.

16:08

But believe it or not,

16:09

osteo radionecrosis is initially a clinical diagnosis

16:13

and it's a little bit frightening to see

16:15

'cause I have patients, uh, present like this in our clinic.

16:18

Literally they're spitting out little fragments

16:20

of bone when they're talking.

16:22

So that's the earliest sign.

16:24

But when we see it on imaging, this is that fragmentation

16:27

of the bone that we see

16:29

with this associated soft tissue enhancement.

16:33

Another example here, this is the natural progression

16:36

of osteo radio necrosis.

16:38

So in this earliest findings, what we start

16:41

to see here is diffuse sclerosis and thickening of the bone.

16:46

And I wanna point out it's just at this point

16:48

just limited to the bone.

16:49

There's no soft tissue abnormality.

16:52

But over time, notice how this bone starts

16:55

to look a little rotten.

16:56

It starts to look a little irregular,

16:58

it doesn't look very healthy

17:00

and eventually it goes on to fragmentation

17:03

and sequestration.

17:04

So this was a normal progression

17:07

of osteo radio necrosis when we first start off

17:10

with sclerosis and then eventually

17:13

we end up into fragmentation

17:15

and eventually pathologic fractures.

17:19

Now this is an example of something that's not associated

17:23

with radiation therapy, but I wanted to point it out

17:26

because it's in that spectrum of diseases

17:30

that involve the bone.

17:33

And I wanna mention this in particular

17:35

because if you do have patients that are treated

17:37

with radiation and chemotherapy, if they are on some type

17:42

of medication that predisposes to osteonecrosis,

17:46

this can exacerbate the bony changes.

17:49

And these are the typical medications that we'll see

17:52

that impair osteoclastic function.

17:55

So this is what we refer to

17:56

as medication associated osteonecrosis

18:00

and these include medications such as bisphosphonate, umab

18:04

and also some of the anti-angiogenic drugs.

18:08

So sometimes where you are evaluating these patients

18:10

and even if they've never had radiation

18:12

or chemotherapy, you can see this typical bone within

18:16

the bone appearance.

18:17

So this is what we see in medication

18:20

associated osteonecrosis.

18:22

So this is the classical appearance on ct as I mentioned

18:26

before, that bone within the bone,

18:28

and again when we look at the mr,

18:30

we can see abnormal signal within the marrow.

18:33

And the way I kind of come up with this diagnosis is if

18:38

that I see this bone looks abnormal

18:41

and then I see direct involvement of the masticator space

18:45

and specifically the macer muscle and the medial OID muscle,

18:50

but I don't see a lot of soft tissue enhancement,

18:53

I don't see a big aggressive mass.

18:55

Then when I see this appearance,

18:57

the first question I always ask is,

18:59

is the patient on some type of bisphosphonate therapy?

19:03

Are they on some type of medication that's gonna allow them

19:06

to have more calcification in their body?

19:09

And you'd be surprised

19:10

how often sometimes our referring physicians

19:13

forget to ask that.

19:14

So when I see something like this, that's one

19:17

of the first questions I end up asking.

19:21

Now the next complication

19:23

that we can see following radiation therapy

19:27

is radionecrosis.

19:29

Now I can't emphasize enough how important it is

19:32

to get those pre-treatment or immediately

19:36

after completion of therapy images

19:38

because this was a patient had an orbital exenteration,

19:42

we can obviously see

19:44

that the right globe has has been removed

19:46

and this patient was treated with radiation therapy.

19:50

Now if we just looked at this image on the right,

19:53

what we see is diffuse thickening

19:55

and enhancement involving the anterior temporal lobe.

19:58

You know, quite frankly there's no way

20:00

that I can separate out whether this is tumor,

20:03

whether it's radiation therapy or it's a combination.

20:07

But on the other hand, when I look one year

20:10

before that, what I see here is I see a little bit

20:13

of an area of enhancement involved in medial portion

20:16

of the right temporal lobe, right in the hippocampal area.

20:19

And this was in the high dose field

20:21

of the radiation therapy.

20:23

So if we see this progress over time,

20:26

this was at the earliest stage, a little bit later we start

20:29

to see it's enlarged, then I'm much more confident

20:33

that we're dealing with radionecrosis.

20:36

And then at this stage we really don't know,

20:38

but this is the important area that we can see.

20:41

Notice how this is separate from the cavernous sinus

20:44

and it's again, it's important to note that this,

20:47

this was actually in the high dose field that was given

20:49

to treat the squamous cell carcinoma

20:52

and this patient had to undergo orbital exoneration.

20:57

Now one of the common things again that we'll run into,

21:01

and this is not only in patients with head, head

21:03

and neck cancer, but if you have a patient with lung cancer

21:06

or if you have a patient with breast cancer,

21:09

especially if they had enlarged lymph nodes involving the

21:12

lower portion of the neck,

21:14

these patients again are oftentimes treated

21:16

with high dose radiation therapy.

21:19

And if the dose is high enough,

21:21

especially if it's greater than 5,500 gray,

21:25

these patients can develop radiation associated

21:28

brachial plexopathy.

21:30

Now part of the question comes in is, uh, is there anything

21:34

that I've learned over time that leads me to believe

21:39

that these imaging findings are due

21:42

to radiation associated brachial plexopathy?

21:45

And the one thing that I've learned over time is

21:48

that when I'm looking at a brachial plexus, MR

21:51

and I don't necessarily see a defined mass,

21:54

but rather I see thickening of the components

21:57

of the brachial plexus

21:59

and it's like someone glued them together.

22:02

So you can see that these brachial plexus, uh,

22:05

components are thickened and they're almost stuck together.

22:08

When I see something like this, then I start thinking

22:11

that this is radiation associated brachial plexopathy.

22:15

Similarly, when we start looking at the stir images

22:18

and some of the vendors have um, the neural view sequences,

22:22

if you will, that are more sensitive to um, the high uh, uh,

22:27

the, the high signal on some of these DWI sequences.

22:30

Um, then again notice the asymmetrical increased signal on

22:34

the left compared to the right.

22:36

And again, this is all consistent

22:38

with radiation associated plex plexopathy.

22:42

Again, you always have to take the dose into consideration.

22:46

If I see this and I know the patient only had 2000

22:50

or 3000 grays, then I'm really more suspicious

22:54

that I'm dealing with tumor.

22:56

But again, if I know that they had high dose therapy

23:00

and it's about a year afterwards, then again

23:02

that gives me more confidence that we're dealing

23:05

with radiation associated brachial plexopathy.

23:10

Now this is one of those things that I'm starting

23:13

to see more and more of.

23:14

Um, it's a little bit more common

23:16

that than I thought it would be.

23:19

These are the radiation associated sarcomas.

23:22

So what radiation associated sarcomas are the following,

23:27

again, they're rare complications after radiation therapy,

23:30

but I am sure you will see them in your practice.

23:33

And what happens is that the radiation therapy

23:37

induces a variety of somatic genetic mutations

23:41

in the treated tissues.

23:43

So if you have a patient with squamous cell carcinoma

23:45

and they're treated with high dose radiation therapy

23:48

on rare occasions, the radiation therapy

23:51

induces somatic mutations into genes such as P 53

23:56

RB and the M gene.

23:58

And as a result, these mutations can result in the creation

24:03

of sarcomas.

24:05

In order for us to make the diagnosis

24:07

of radiation associated sarcomas, the

24:12

sarcoma has to be associated in the irradiated field

24:15

and the dose is typically greater than 6,000.

24:18

It has to be four years after the completion of therapy.

24:23

And this tumor must be histologically distinct

24:27

from the initially treated tumor.

24:30

So this is an example of

24:33

a radiation associated osteosarcoma.

24:36

This patient previously had a laryngeal carcinoma

24:39

that was resected treated with high dose radiation therapy.

24:42

In fact, we can see the flap right here in here.

24:46

We can see the new bony changes

24:48

and this large soft tissue mass.

24:50

And this was radiation associated osteosarcoma.

24:54

Another example here we can see a large mass right here

24:57

involving the masticator space.

25:00

This was radiation associated fibro sarcoma.

25:03

And on this one, again,

25:05

I think we can make the diagnosis here.

25:07

We can see this new bone formation,

25:09

this periosteal reaction associated with a soft tissue mass.

25:13

And again, another example of radiation associated sarcoma.

25:18

So again, in order to make this diagnosis, it has

25:21

to be high dose, it has to be typically at least four years

25:26

after the completion of therapy

25:28

and the histology must be distinct

25:31

from the initial tumor that was treated.

25:35

Okay? So what we've done so far is that we talked about

25:40

complications and expected changes after chemotherapy

25:44

and radiation therapy.

25:46

Now what we're gonna do is

25:48

that we are now gonna change our focus to surgical changes.

25:52

And the first thing that we're gonna talk about in surgery

25:55

is just a simple resection.

25:58

So this is what's referred to as primary closure.

26:02

So this patient had a mass right here involving

26:05

the parotid gland.

26:06

So this was pre-op

26:08

and post-op, we can see here the mass was resected

26:12

and there was no flap, nothing was really done.

26:15

They just close it up and the patient was done.

26:18

And in generally when you have this type of primary closure,

26:22

just basically a simple over, so there are not a lot

26:26

of complications associated with this, the most common thing

26:29

that you'll run into is something like this is,

26:32

which is an abscess.

26:34

So preoperatively,

26:35

this patient had a pleomorphic adenoma in this case

26:39

involving the paranal space.

26:41

And what the surgeons did is they waited and operated on it

26:45

and afterwards unfortunately this patient

26:47

developed an abscess.

26:49

So this is the most common complication

26:52

that you'll end up seeing

26:54

after primary closure, following primary resection.

26:57

So again, for a primary closure, not too much that you have

27:02

to worry about, but on the other hand,

27:07

when you have more extensive resections, the surgeons have

27:11

to figure out a way how to close

27:14

that surgical defect up.

27:17

And one thing that they'll do is they'll place a graft.

27:21

So we talked about resections

27:23

and now we're gonna talk about resection plus the PA

27:26

placement of a graft of tissue.

27:30

So first of all, let's talk about definitions.

27:33

What exactly is a graft?

27:36

A graft is when a surgeon moves one part of

27:40

tissue from one part of the body

27:43

and moves it to another part of the body

27:46

without taking the native blood supply.

27:49

And the most common graft

27:51

that you'll end up seeing in the head

27:53

and neck is going to be a fat graft.

27:55

So this is a fat graft that was placed

27:57

because this patient had a surgical defect

28:00

and they needed to fill up that defect.

28:03

So as I mentioned before, the most common thing

28:05

that we'll see on imaging is gonna be a fat graft,

28:09

but actually the most common graft

28:11

that's used in reconstruction, the head

28:13

and neck is gonna be a skin graft.

28:14

But in general, we don't do a lot

28:16

of imaging following skin graft,

28:18

but we do do a fair amount of imaging following a fat graft.

28:23

So when we do talk about our imaging,

28:25

we'll focus on the appearance of a fat graft.

28:28

So here's probably the most common thing that you'll see

28:33

in a fat graft.

28:35

So this was a patient that has a vestibular schwannoma

28:38

that's involving the left internal auditory canal.

28:42

So we can see the enhancing vestibular schwannoma.

28:46

Now when the surgeons resect this

28:48

and specifically the ENT surgeons, what they end up doing is

28:52

that they end up starting from the outside and working in

28:56

and they drill out the mastoid bone.

28:58

And this is what's referred to as a mastoidectomy.

29:01

So they perform a mastoidectomy

29:04

and notice what's happened when they performed their

29:07

mastoidectomy, they drill through the mastoid bone

29:10

and then once they get to the Petra apex,

29:12

now they have really good exposure of the four nerves

29:17

that comprise the vestibular cochlear nerve.

29:20

So as a result,

29:22

the surgeons are actually staying within the mastoid bone,

29:25

they're extradural

29:26

and this gives them the ability

29:28

to resect these vestibular schwannomas.

29:31

But then the issue comes is that in general,

29:34

you know the surgeon just can't lead this mastoid cavity,

29:37

they have to fill it up with something.

29:40

And the most common tissue that they end up filling this up

29:43

with is gonna be a fat graft.

29:45

So this is an example of the triangular appearance

29:49

of a fat graft that is placed in following resection

29:53

of a vestibular schwannoma.

29:55

And once you've seen one,

29:57

it's almost like pattern recognition.

29:59

It really looks like a piece of pie,

30:02

just this triangular area that's been filled in

30:05

to fill up this defect.

30:07

So this is what this looks like on the

30:09

non-contrast T one weighted images.

30:11

We can see that it's bright on T one is what we would expect

30:14

after the after the fat is placed.

30:17

And this is what it looks like on the

30:19

heavily T two weighted images.

30:21

So this is what we expect

30:23

to see in a completely resected vestibular schwannoma.

30:27

But this on the other hand is the presence of recurrence.

30:31

So now here's the CYS image right here we can see this

30:35

triangular piece of fat.

30:37

That's the graft that we see.

30:39

And if you look real closely,

30:41

we see this little soft tissue mass here on the

30:44

heavily T two weighted images.

30:46

Now, just based on this,

30:48

we don't know whether it's fibrosis,

30:50

we don't know whether it's recurrence, we're just not sure.

30:53

When we look at the non-contrast T one weighted image,

30:57

again we can see that nice triangular piece of fat

31:00

that's been placed in the defect.

31:02

But when we give contrast, we see this focal area

31:06

of enhancement right here, which is at the resection side.

31:09

And this in fact is what a recurring a recurrence

31:13

of a vestibular schwannoma looks like.

31:16

Now, what's quite possible,

31:17

this may have been incompletely resected, I don't know that

31:20

for sure, but this area of enhancement, notice

31:23

how it's focal and it's nodular.

31:26

This is what, uh, which is indicative

31:28

of recurrent vestibular schwannoma.

31:31

So this is what we've gone so far is

31:34

that this is the expected appearance,

31:37

this is the appearance of recurrence.

31:40

And now what are some potential complications

31:42

that we can see in a fat graph?

31:46

So up on the top right hand area is

31:49

what we would expect to see.

31:50

This is that triangular piece of fat.

31:53

This is an example of a seroma.

31:56

So superficially we can see part of

31:58

that fat graft right here,

32:00

but notice it doesn't kind of peter down into

32:03

that normal apex.

32:04

It doesn't look like that triangle.

32:06

So it's low signal on T one, high signal on T two.

32:10

And we can see this uh, fluid right here.

32:14

And this is the typical appearance of a seroma that can, uh,

32:18

that can occur because remember these fat graft do not have

32:22

a native blood supply.

32:24

And if somehow that blood supply,

32:26

if somehow if this fat starts to liquefy

32:29

or necros, we can develop a ELLA

32:32

and then over time we can actually develop fat necrosis.

32:36

So this was an example again of a patient

32:39

that underwent a mastoidectomy defect.

32:42

This was a fat suppressed image.

32:44

And in June of 2000, uh 20, uh, uh, June of 19,

32:49

we can see this little area of increased T one signal.

32:53

And then look what happened to it.

32:54

Five years later, all of a sudden this expanded

32:58

and this turned into proteinaceous material

33:01

and this was the natural evolution of fat necrosis

33:04

that occurred in this fat graft.

33:08

Now on very rare occasions, what can happen is

33:12

that you can actually have migration of fat

33:15

into the posterior fossa.

33:17

So this is the normal appearance of the fat here.

33:20

Remember, once you've seen one, you've seen 'em all,

33:22

you can see this triangular pie right here.

33:25

And in this case, what we see here are these GLTs of fat

33:29

that have migrated through the dura

33:31

and are actually located in the posterior fossa.

33:37

So this was a rare example

33:39

of fat migration into the posterior fossa.

33:44

Now the last thing that we'll talk about is resection,

33:49

followed by a flap reconstruction.

33:51

So remember, a graft is soft tissue

33:54

that's moved from one part of the body to another part

33:57

of the body that does not have its blood supply.

34:01

Now what a flap is, is you remove one part of the tissue

34:05

to another part of the tissue,

34:07

but you maintain the blood supply.

34:10

And if you are dealing with patients that uh, of you know,

34:14

a good group of ENT surgeons

34:15

that are doing these large resections, these are the ones

34:19

that are gonna have to reconstruct these larger resections

34:22

with these big flaps.

34:24

So this was the patient that underwent a laryngectomy.

34:27

We can see a resection of the larynx here.

34:29

In fact, you can see the epiglottitis

34:31

and this patient underwent a mandibular.

34:34

We can see the mandible has been resectioned,

34:37

this patient underwent a maxillectomy

34:40

and this patient actually underwent orbital exenteration.

34:45

These are very, very big procedures that are being done.

34:48

And the reason that you use a flap is that the whole purpose

34:53

of the flap is really primarily threefold.

34:56

First of all, cosmesis, you know,

34:59

you just can't have a patient leave the operating room

35:02

with a defect in the mandible.

35:04

So from cosmetically you have to try to reconstruct it

35:08

and try to return as much native appearance for

35:12

that patient as possible.

35:14

Second is function.

35:16

You know, once you do a procedure such

35:18

as a mandi bullectomy, the patients need to be able to talk,

35:21

they need to be able to eat, so on and so forth.

35:24

So they have to have, try to maintain

35:26

as much function as possible.

35:29

And then finally, oftentimes these patients

35:32

with these LA large cancers are being treated with some type

35:36

of adjuvant therapy.

35:37

And if you have a really good flap like this,

35:41

this can decrease complications associated

35:44

with adjuvant therapy.

35:46

So when you are dealing with these very,

35:48

very large resections, remember the goals

35:51

of flaps are cosmesis function

35:54

and decrease complications.

35:57

Now look, I can give

35:58

and I do have a talk, uh, 35 to hour talk purely on flaps.

36:04

Um, and I'm gonna talk a little bit about flaps,

36:06

but one of the the key things that I want to leave

36:09

with you is that when we talk about flaps

36:12

is this concept is like to like, so

36:16

what I'm gonna show in the next few slides

36:19

are a bunch of flaps.

36:21

But what I wanna remember is the concept of like to like,

36:25

and that is if you remove soft tissue, then the type of flap

36:30

that you're gonna reconstruct

36:31

with is predominantly gonna be soft tissue.

36:35

If you remove bone, then the type of reconstruction

36:39

that you're gonna reconstruct with is going to have

36:42

to contain bone.

36:43

And that's the whole concept of light to light.

36:46

So if we remove soft tissue, you wanna

36:49

reconstruct with soft tissue.

36:51

If you remove bone, you wanna reconstruct with bone.

36:55

So let's begin our journey.

36:58

So when we talk about flaps,

37:00

these flaps can be classified based on origin.

37:04

So a local flap is basically like a skin flap.

37:07

This patient has a defect right here.

37:09

You can take some skin and rotate it over

37:13

and close the flap.

37:14

This is what we mean by a local flap.

37:17

You can also use a flap that's a pedicle.

37:20

This is an example actually of a pectoralis muscle

37:23

that was freed up and is now rotated.

37:26

And you can see our pedicle here.

37:29

And one of the most common flaps

37:31

that you use is we take tissue from one part of the body

37:35

and put it in the other part of the body.

37:38

And this is what's referred to as a free flap.

37:40

So if you ever have heard of a free

37:42

flap, this is what it is.

37:43

We take one tissue from one part

37:45

of the body completely freed up

37:48

and we move it to another part of the body.

37:51

So this type

37:52

of classification is based on the origin of the tissue.

37:56

This is again adjacent.

37:57

This is a pedicle

37:59

and this is free tissue taken from

38:01

one place to another place.

38:03

But the other way to classify these flaps

38:08

is based on the tissue type.

38:10

So you can have a single tissue type, as I mentioned here.

38:13

This was skin, this was muscle, that's a single tissue type.

38:18

But most commonly we have what we refer to

38:21

as a composite type.

38:23

So this is muscle

38:25

and skin, this is myocutaneous, this is osteo cutaneous

38:30

and this is fascia cutaneous.

38:32

But the takeaway point that I want you

38:34

to have is remember light to light.

38:37

If we are just removing some type of soft tissue,

38:40

we're gonna reconstruct with some type of fat and skin.

38:44

If we are removing bone, then we're gonna have

38:47

to reconstruct with some type of bone.

38:50

Just remember that because this will help us as we now start

38:54

to look at these cases.

38:57

So this is an example of a patient

38:59

that has a cancer involving the posterior floor of the mouth

39:03

and the tongue base, the bone was not involved.

39:07

So this patient underwent a glossectomy.

39:09

So this soft tissue was removed.

39:12

So now what we see here is that the tongue is removed

39:15

and we see something that contains just fat.

39:19

Why was this? Because this was fasio cutaneous.

39:22

This is just flap.

39:24

Now when we're looking at the expected changes,

39:27

where my eye automatically goes to is this all

39:32

of this fat right here?

39:33

So this fat, this is where my eye goes to

39:35

and then I start seeing these vascular clips.

39:39

But what I want you to concentrate on is learn how

39:42

to not necessarily look in the middle

39:45

because all of this has been resected, this is

39:47

where the tumor was, but the tumors recur at the margin.

39:52

So this is another example.

39:54

This is an example of a patient

39:56

that had a partial glossectomy and had reconstruction.

40:00

But notice the recurrence is not gonna be in the center,

40:03

it's gonna be in the peripheral.

40:04

And this yellow arrow points it where the tumor is.

40:08

Another example here,

40:11

we our eye naturally goes to here, right?

40:13

Because that's the conspicuity, this is that flap.

40:17

But the yellow arrow points at this soft tissue right here.

40:21

And this is where the recurrent tumor is.

40:23

And this is along the margin.

40:25

So as you start looking at these postoperative appearances,

40:29

crane your eye to look at the margins

40:32

because that's where the marginal

40:33

recurrences are going to be.

40:36

Another example here,

40:38

this patient ended up having a tumor

40:40

involving the floor of the mouth.

40:42

This was actually fixed to the mandible,

40:44

so the mandible had to be resected.

40:47

So as a result, the type of reconstruction

40:50

that was performed had to involve the fibula

40:53

because this bone has to be reconstructed.

40:56

So this is an example of an osteo cutaneous flap,

41:02

osteo bone cutaneous skin.

41:06

So this is a mandibular reconstruction.

41:09

So again, when your eye goes to this, this is

41:12

where your eye goes to, it goes to the bone

41:15

and it goes into the soft tissue.

41:17

But again, you have to train yourself

41:19

to look along the margin.

41:21

So in this particular case, our eye goes to here

41:24

where the fat is, but train yourself to look at the margin.

41:28

This is where that recurrence was,

41:30

it was along the margin of that tumor.

41:33

And also if you have a really good eye, you can also see

41:37

that this patient recurred in a lymph node.

41:40

So this tumor recurred along the margin

41:42

and they recurred in the lymph node.

41:45

So in order to be to pick up those recurrences, you have to

41:50

remember to always look at the margin.

41:52

And that's something I've tried

41:53

to focus on over the last 15 years.

41:57

So what we've done so far, again, when we talk about

42:01

surgical resection, remember a flap is a piece of tissue

42:05

that's moved from one part of the body to the other,

42:09

but it maintains its native blood supply.

42:12

It has to have a blood supply.

42:15

Now what are some complications that we can have?

42:19

Well, one of the first complications that is

42:21

that we can have hardware loosening.

42:24

So this was a patient actually had a

42:26

mandibular reconstruction.

42:27

So in order to reconstruct this, what they do is

42:31

that they take a piece of fibula.

42:33

And at most institutions right now,

42:35

it's really quite amazing.

42:36

They'll do a preoperative ct, they'll take that ct,

42:40

they'll do 3D reconstructions,

42:42

and literally the, the a a little panel

42:46

or a little plate will come, a template will come

42:49

and it'll literally tell the surgeons where

42:51

to make the cuts in the fibula

42:53

and actually where to drill the screws

42:55

and where to place the plates.

42:57

So it's almost like a, you know, the surgeons are being told

43:00

where to cut and where to place their screws.

43:03

And so as a result, one of the complications

43:06

that can happen, it's that some

43:08

of these screws can sometimes get loose.

43:11

So this was a screw that was actually

43:12

placed in the mandible.

43:14

But notice this space right here.

43:16

It's actually start to unwind

43:18

and this is what's referred to as hardware loosening.

43:21

So when the 3D was done, the screw was placed,

43:25

but over time the screws become loose.

43:28

And this is what's referred to as loosening of the hardware.

43:33

Another example of a complication is extrusion.

43:37

And I've seen patients like this

43:38

and it was really one of the most amazing things I've seen.

43:41

So when you have mandibular reconstructions, you reconstruct

43:45

with bone and you can reconstruct with a plate.

43:49

Now, unfortunately in some situations what happens is that

43:53

that plate actually starts to extrude through the skin.

43:57

And I remember the first time I saw this,

43:59

I walked in the patient's room

44:02

and oh my gosh, I saw this metal plate that had come out

44:05

of their skin and I was literally looking at 'em.

44:08

And the interesting thing enough is

44:10

that the patient really wasn't in a tremendous amount

44:12

of pain, it was just a discomfort.

44:15

So you know, it actually looks a lot worse than the amount

44:19

of symptoms that the patients are having.

44:22

But certainly cosmetically it's something

44:24

that you don't wanna see.

44:26

So the typical way that you work up these patients is just

44:29

with a regular plain film.

44:31

But this was just a CT scan here of a complication

44:35

of a plate that had extruded through the skin

44:38

and is now visible to the visible eye.

44:41

So basically this is the correlate of

44:43

what we see here in this clinical picture.

44:47

Another complication that you can see is fistula formation.

44:52

So again, this was an example of a patient

44:55

that underwent total glossectomy

44:57

and we can see the reconstruction.

44:59

So remember like to like this was a patient

45:02

that had the tongue removed.

45:04

This was reconstructed with a free flap

45:06

and this was a fascia cutaneous flap.

45:09

So it was just fat.

45:11

But over time, over one year period,

45:13

what ended up happening is

45:15

that this patient developed a fistula formation.

45:19

So notice the skin right here, the skin defect.

45:21

And there was, this was continuous with the soft tissue

45:25

that was just below the flap.

45:27

And if you look just under it,

45:29

we can see really the early beginnings

45:31

of a fistula formation.

45:33

Now there's no way for us to exclude tumor here,

45:36

we just can't do it.

45:38

But what the surgeons will sometimes do is take a small

45:41

little PEO scope, they'll actually stick it in

45:43

and then look at the mucosa just

45:46

to make sure there's no tumor in this.

45:48

But this was just an example of fistula formation

45:52

that developed over a six month period.

45:56

Now if you have a complication that patients develop fever,

46:00

well you can end up developing osteomyelitis and flagg mod.

46:04

So this was an example of osteomyelitis

46:06

that develop an infected flap.

46:09

We can see the bone erosion

46:11

and we can see the the modeling of the bone

46:13

and the sequestration and the destruction.

46:16

And in this case, when we look at the contrast enhanced CT

46:19

scan, we can see this diffuse flag mount.

46:21

So this is flag mount associated with bone erosion

46:26

and we can go to that next phase

46:28

and that theleman starts to develop fluid

46:31

and gets walled off.

46:32

Well this was an example of a patient preoperatively

46:35

that had a laryngeal carcinoma, was treated

46:38

with a total laryngectomy, was treated with a free flap

46:41

and unfortunately this patient developed a large abscess.

46:45

So you can have infectious complications which are

46:48

osteomyelitis and phlegm mod,

46:50

but if it continues to persist, this is go on to form

46:54

a true abscess.

46:57

Now on some occasions you can actually have hematomas.

47:02

So this was an example of a patient

47:04

that had a retromolar trigone carcinoma

47:07

and that was reconstructed with,

47:09

in this case a myocutaneous flap.

47:12

And this was that pedicle flap that I talked about.

47:15

So here we can see the resection of the mandible.

47:17

This pedicle this, this little pectoralis major was kind

47:21

of tucked away and this is the expected

47:23

appearance that we would see.

47:26

This on the other hand was a hematoma of the flap.

47:30

So this was that same type of flap

47:32

that we can see the fat right here.

47:34

But unfortunately this patient developed a large hematoma

47:38

and here we can see the diffuse enhancement around the flap.

47:41

So up top here is the expected appearance

47:45

and below this is what happens in this unfortunate case,

47:49

which was a hematoma

47:50

that occurred in the flap that was placed.

47:55

Now this is the most challenging area and this is necrosis

47:59

and failure and this is what you don't wanna see.

48:02

So this was the page

48:03

that underwent a large squamous cell carcinoma.

48:06

This was actually following the placement of the flap.

48:09

You can see it doesn't look the healthiest already.

48:12

Again, light to light.

48:14

We should see low attenuation here, we should see that

48:17

that a fascia cutaneous appearance.

48:20

But unfortunately this was a flap that was failing.

48:23

And over about a five month period we can see

48:26

that this whole flap completely necros out.

48:29

So this is all air and necrosis that occurred in this flap.

48:33

So this is what we don't wanna see.

48:36

Typically these flap failures occur within 24 to 48 hours

48:41

after the placement of it.

48:42

To actually see this type

48:45

of delayed flap failure necrosis is a pretty rare,

48:49

a rare situation.

48:50

Now from our standpoint, again,

48:52

I cannot exclude the possibility of tumor,

48:55

but oftentimes these are fairly clinically obvious.

48:58

But you, because you can imagine all the flap just literally

49:01

starts to drain out in front of you.

49:03

So it's not the, certainly the nicest thing to see.

49:07

And the last slide that I wanna leave you with is this.

49:11

So this was a patient that had a total ectomy, was treated

49:16

with a large flap.

49:17

So we can see some fat right here.

49:19

We can see some muscular components, et cetera.

49:23

Now this patient started spitting up blood.

49:27

So in

49:28

or when they start to split up blood,

49:31

what you worry about is some type of vascular injury.

49:35

So this is a CT angiography.

49:37

So notice at this level right here,

49:40

all the contrast is in the vessel

49:42

and the contrast is in the vessel.

49:43

So these are the internal carotid arteries

49:46

and these are the vertebral arteries.

49:49

Now when we look a little bit lower, unfortunately

49:52

what we start to see now is

49:54

that we can see flow in the carotid,

49:56

but notice how there's extravasation of contrast

50:00

extending into the soft tissues.

50:02

And this is a coronal imaging

50:04

and we can see this contrast material extending out.

50:08

Well this is the typical appearance of a carotid blowout.

50:13

So if you see something like this, be very,

50:15

very worried in call your interventional neuroradiologist up

50:19

because this is the classical appearance

50:22

of a sentinel bleed.

50:24

So this was a patient that had a large carcinoma,

50:28

was treated with surgery and radiation therapy.

50:31

Notice the narrowing of the internal carotid artery.

50:34

But despite this, there is a little aneurysm right here.

50:38

This was a pseudo aneurysm

50:39

that ended up bleeding and blowing up.

50:42

And this was the same case that I'm showing on the CTA

50:46

and this little tiny aneurysm here

50:49

resulted in this large carotid blowout

50:51

and the extravasation of contrast.

50:53

So I just wanna make sure that you're fully aware of the ct,

50:57

an angiogram appearance following carotid blowout.

51:02

So in summary, what we've done over the last 15 minutes is

51:07

that we talked about the different types of ways

51:11

that patients are treated.

51:12

They can be treated non-surgically or with surgery.

51:16

We talked about the expected appearance,

51:19

we talked about some of the surgical reconstructions.

51:23

And then what I wanted

51:24

to do was provide you a checklist of things.

51:27

So sometimes when we are seeing these post-treatment

51:30

changes, you know, we don't even know where to start from.

51:34

So what I hope to do is at least give you an approach

51:36

and a list of things to look for.

51:38

So at the very least you can at least have pertinent

51:42

negatives and say there's no evidence of infection,

51:44

there's no evidence of ischemia, there's no fat necrosis,

51:47

so on and so forth.

51:49

So at least you have an approach

51:51

and hopefully this will give you a better sense of

51:54

what depletion your reports

51:56

and overall help you improve the outcome of your patience.

52:00

So thank you very much for your attention

52:02

and um, I'm happy to take any questions.

52:06

Thank you so much for that wonderful lecture Dr. McCury.

52:09

And yes, at this time we will open the floor for questions.

52:13

You can put those into the q

52:15

and a feature that'll help us stay on track

52:17

and get through as many questions as we can.

52:20

We can. So there's already several in that q and a box, Dr.

52:24

McCury, if you wanna pop that open.

52:27

Sure. Might be at the top of your zoom you got, okay,

52:32

Great. Yeah, can you

52:33

see my screen here?

52:34

I don't know if you can see it or not.

52:35

So, um, so should, should I read 'em out

52:38

or do you wanna read 'em out?

52:40

Up to you. Okay. Um, I can read out the first one.

52:44

So it a, thanks for the talk. It's from Kai Kim.

52:46

Uh, does chemotherapy include treatment, biologics,

52:49

biosimilars, or small MO molecules?

52:52

Um, so, um, that's a great question.

52:55

So the chemotherapy

52:56

that I discussed in this talk is predominantly the standard

53:00

cisplatinum because most head

53:02

and neck cancers will be treated with radiation therapy

53:05

and, and cisplatinum.

53:06

Now purely based on time, you know,

53:09

I did not discuss immunotherapy.

53:12

So immunotherapy is being used more and more frontline

53:17

and there are certain complications that are associated

53:19

with immunotherapy and a lot

53:22

of the immunotherapies are basically the revving up

53:25

of our immune system.

53:27

So in immunotherapy you can have things like

53:31

pseudoprogression, there's something called

53:33

hyper progression.

53:34

And because the immunotherapy kinda revs up your immune

53:38

system, you can have things like pituitary hyperplasia,

53:43

you actually can have types of thyroiditis.

53:46

In general, the complications associated

53:48

with immunotherapy are rare, um, but they can see them.

53:52

But this talk specifically was predominantly used

53:55

for the standard chemotherapy, uh, regimens, um,

53:58

that you'll see predominantly in your practice.

54:02

Um, the next one is from om. Hi M. It's good to see you.

54:06

Thanks for joining. Um, the next one is that

54:11

do we use the RAD system in the follow-up studies?

54:14

Um, I think rad, um, can be helpful.

54:17

Um, it's the RAD system basically is

54:22

a four tier system where it's either, uh,

54:25

definitely positive, probably positive,

54:29

probably negative or negative.

54:31

And it's also based on on time.

54:33

So in general, I don't necessarily use NI rrAD,

54:37

but I do um, suggest that in patients that are high risk

54:42

of recurrence, um, those are the ones, uh,

54:45

that should be getting, um, um, PET ct.

54:47

So we don't use the the RADS to the full extent of it,

54:52

but the whole concept of if I'm not sure, um,

54:56

whether something, if I'm not clear,

54:58

whether something's definitely recurrence

55:00

or something hasn't recurred in those indetermined cases,

55:03

then we would recommend PET CT in a way, which is a form

55:07

of RADS approach.

55:10

Um, the next question is do we use a SL

55:13

to differentiate radiation change in and tumor recurrence?

55:17

Um, it's a really good question.

55:19

Um, in general where I have found a SL

55:23

to be most beneficial is really

55:25

for nasopharyngeal carcinomas.

55:27

I think when we are looking, uh, at soft palate

55:31

and into the larynx, the A SL,

55:34

the technique can oftentimes be, uh, affected

55:38

by artifact, either motion artifact

55:41

or susceptibility artifact from the air, et cetera.

55:45

I think a SL can be very beneficial for skull-based tumors,

55:48

especially for nasopharyngeal carcinomas.

55:52

Um, after treatment, especially for NPC, sometimes it's hard

55:56

to determine whether or not there's post-treatment changes

55:58

or whether there are recurrent tumors.

56:01

So I think a SL um, can be beneficial.

56:06

The challenge is that there really aren't any, you know,

56:09

large trials that have path correlation suggesting that

56:14

what we see on the imaging is

56:17

actually been pathologically proven.

56:19

But on the other hand, if you have a patient that you're,

56:23

that's clinically unclear and you did do a SL

56:28

or any type of perfusion and there was increased blood flow

56:32

and increased blood volume, that may be enough to,

56:36

to push the radiation oncologist to reradiate

56:41

or potentially the, uh, medical oncologist

56:44

to provide chemotherapy.

56:46

So that's at least where I've seen to be a SL

56:49

to be more beneficial.

56:52

Um, the next question is

56:54

can diffusion imaging differentiate radionecrosis

56:58

and recurrence or infection?

57:00

So, um, the answer is yes, but I wanna give a little caveat

57:05

and that is in I find first of all

57:10

with diffusion imaging, you have to make sure

57:12

that your technique is really good.

57:14

So you have to have really good technique, um, you have

57:17

to have the right coils.

57:19

And in general for radiation necrosis, there has

57:22

to be a certain amount of

57:26

tissue there.

57:28

And what I mean by that is diffusion is not gonna be helpful

57:33

looking for microscopic disease.

57:35

You know, it's just impossible.

57:37

But on the other hand, if you really do have a mass

57:40

that you can see that's, uh, two or three centimeters

57:44

and you don't know whether or not it's a recurrence

57:46

or not, then I think the DWI can be helpful,

57:50

but it's not definitive for me.

57:52

Diffusion weighted imaging is additive,

57:55

so it is can be a problem solver.

57:58

So I still predominantly rely on my standard CT images.

58:02

I provi I rely on my base MRI sequences

58:06

and then if I'm still not sure,

58:07

then I will look at the diffusion.

58:10

But diffusion is not the first sequence that I turn to

58:14

because of the potential artifacts

58:16

and the potential, um, technical issues

58:20

that can be associated with diffusion

58:22

unless you really optimize, uh, sequences that you have.

58:28

Um, the next one is why would the hematoma enhance in the

58:33

complicated case of flap?

58:34

And thank you. Uh, thanks for your kind words.

58:37

So the hema, what ends up happening

58:39

with the hematoma is typically you have the periphery

58:42

enhancement, I think the case that I showed,

58:45

let me see if I can, oops, sorry about that.

58:47

Let me see if I can go back.

58:49

The case of the hematoma that I showed.

58:51

Yeah, this was it right here.

58:54

Um, notice how it's the periphery that's enhancing

58:58

and not centrally

59:00

and obviously the reason it's not enhancing centrally is

59:03

because this is the liquification of the blood products

59:07

as opposed to the peripheral area here, which is that area

59:11

of, of enhancement probably due to the inflammation

59:16

caused by that hematoma.

59:19

Um, uh, is it actually leaking as opposed to

59:23

to form the clot?

59:24

Um, I assume that you're talking about this, um,

59:27

it's probably a combination of the two.

59:30

Typically by the time we image the acute blood is gone

59:34

and now we're sort of dealing with this residual hematoma,

59:37

which is probably why we're seeing the enhancement at the

59:40

periphery, um, which is where we'd expect

59:43

to see the enhancement.

59:46

Um, the next question is differentiating

59:50

or n from osteomyelitis from recurrence.

59:52

And this is a great question.

59:54

Um, so sometimes it can be difficult.

59:58

So I can tell you when I'm actually seeing the patients.

60:02

Um, if you have patients that have ORN,

60:06

they typically are afebrile

60:08

and do not have any large masses

60:12

that are seen on physical examination from an imaging.

60:16

And so typically what happens if clinically

60:21

if the surgeons are trying to distinguish between ORN

60:25

and osteomyelitis, they'll go ahead

60:27

and be treated with a course of antibiotics to see if

60:30

that helps them resolve.

60:31

So clinically sometimes it can be ha a hard

60:34

to distinguish the two.

60:36

This I think is a great example of when to use PET ct

60:40

because if you are trying to look for recurrence versus ORN

60:45

or osteomyelitis,

60:47

I'm not a big SUV fan standard uptake value,

60:50

but in general, recurrences are gonna have higher SUVs than

60:54

compared to osteomyelitis or ORN.

60:57

The other thing too is that with recurrence,

61:00

the recurrence tends to be a little bit more focal,

61:03

whereas the osteomyelitis

61:05

and the ORN tend to be a little bit more diffused.

61:08

So when you're trying to distinguish between ORN and

61:11

and uh, recurrence, then clearly that's a great opportunity,

61:16

um, to use PET CT to help separate those two.

61:21

Um, seroma duration, is it formed and resolved?

61:27

In general? I would say that if you have a seroma

61:30

and it's within a free flap, oftentimes

61:35

that seroma does not go away by itself.

61:37

It tends to preserve and stay there over time.

61:40

So, you know, obviously I haven't in follow-ups on every

61:43

seroma I've ever seen, but

61:45

what I can say is once I've seen a seroma, um,

61:48

form in a graft, a fat graft, it tends to stay there

61:53

and tends not to resolve.

61:54

So to me, at least in my experience,

61:56

they've been relatively consistent

61:58

unless they've been drained.

62:01

Um, is there anything we can do

62:04

to prevent the complications from radiotherapy?

62:08

Um, and I would have to have a little bit more clarity on

62:12

that, meaning that, um, from an imaging standpoint,

62:17

so this was Saha Saha, maybe you can just, um, follow up,

62:21

up on the q and a.

62:23

'cause, um, I I'm not sure if you mean from an imaging

62:26

standpoint or, uh, whatever to prevent complications.

62:29

So I don't, I don't know if I can answer your question

62:32

accurately unless I get a little bit more information, um,

62:36

as to what you're referring to.

62:37

Apologies for that.

62:40

Uh, the next question is, in a case

62:42

where the individual had an accident

62:45

and the mandible is broken, um,

62:50

the individual had an accident, the mandible is broken,

62:52

what actually to the face?

62:54

Um, I don't know how to answer that one.

62:59

Um, I don't n Nixon, I don't know

63:03

how to answer that one either.

63:04

Um, Ashley, do you have any que uh, suggestions on that one?

63:08

That one I can't answer.

63:09

Um, 'cause I'm not sure what you're asking

63:12

so I apologize for that one. Um,

63:15

I don't, um, perhaps that person

63:17

who asked the question can clarify

63:20

with another question. Okay.

63:22

Alright. Um, Arif and eSSH and Ashwin

63:27

and Nixon, thanks for your car.

63:29

Hi Carla. Thanks. Uh, thank you very much. Um, let's see.

63:36

Yeah, or N versus osteomyelitis pet.

63:38

The answer is, um, you know, from,

63:41

or n versus osteomyelitis.

63:43

I don't, um, I don't know if pet's gonna be helpful for O

63:48

or N versus osteomyelitis.

63:49

Both of those have low level inflammations.

63:53

Um, and I just don't know if it's gonna be helpful.

63:57

I think certainly if you wanna exclude

63:59

recurrence, it'll be helpful.

64:00

But ORN versus, um, osteo, I don't know if it's gonna be,

64:04

I dunno if it's gonna be that helpful.

64:07

Let's see, what was I, um, case

64:12

where the individual has an ax in the middle of Brook,

64:14

I do face yes.

64:17

Imaging standpoint. Let, oh, I see what you're saying.

64:20

Um, yeah, so Jata, I think I know what you're saying.

64:24

I, I think, you know, that's an interesting question.

64:26

I think it's, it, I think it is important.

64:30

Maybe the question behind the question is, in general,

64:34

what we can do is to be very precise as to

64:38

where we think the margins of the tumor is.

64:42

So one way to think about is if, if,

64:46

if we just say there's a tumor there

64:48

and we sort of leave it up to the radiation oncologist

64:51

to give more dose

64:53

or maybe, um, it's staged higher than it should be,

64:57

then those patients would be more likely

65:02

to develop complications

65:03

because they may be overtreated, if you will.

65:07

But on the other hand, if, if you, if, if you are confident

65:10

to saying that this is where you think the tumor is

65:13

and where it's arising from,

65:15

then the radiation can be more focused

65:19

and the patients can be treated appropriately as opposed

65:22

to overtreated.

65:24

So that could potentially reduce some of the complications.

65:29

Um, so how do we, that's a, so

65:32

that's a really great question that the next one is, um,

65:35

how do we, how do we word

65:37

or report when we're not sure whether it's

65:40

radionecrosis or recurrent?

65:42

So that's a great question.

65:45

So what I end up doing is

65:46

that I'll end up saying there's an abnormality.

65:49

Um, and what I would end up saying is, um, if I'm really,

65:54

really not sure then I would probably just go ahead

65:58

and recommend a pet ct.

66:00

Um, in general, like someone mentioned rads, which is uh,

66:04

kind of a standard approach to it, which is, which is fine.

66:08

Um, I tend to first make sure

66:11

to see if I can problem solve based on the imaging findings.

66:14

And if I don't know for sure, that's when I'll go ahead

66:17

and recommend a pet ct.

66:18

So I will say, you know,

66:20

I'll mention the descriptive findings, whether

66:22

or not there's fragmentation of bone,

66:24

whether there's an enhancing soft tissue mass.

66:27

I'll also compare it to the prior study to see whether

66:29

or not the masses increasing in size,

66:32

whether there's more bone fragmentation.

66:35

And after I give all that description

66:37

and I'm still not sure, then I will go ahead at

66:40

that time then recommend a pet ct.

66:44

Um, let's see.

66:48

So this is a, a, again, a great question here.

66:50

Picking up on the or N versus recurrence subject,

66:54

can the time of the appearance

66:56

of the abnormality be helpful in differentiating This is

66:59

100% Yes.

67:01

So if I start to see an enlarging mass within six months

67:05

after treatment three to six months

67:07

after treatment, then I'm pretty confident I'm dealing

67:11

with recurrent tumor as opposed to

67:15

complications associated with radiation therapy.

67:18

Because remember the radiation therapy associated

67:21

complications typically occur a year out

67:24

and they're also associated with higher dose of therapy.

67:28

The other thing too is

67:30

that remember if you see an enlarging mass

67:33

that occurs in a lymph node, then

67:35

that's definitely gonna be recurrence.

67:37

So when you do see these masses enlarging over time,

67:41

if it's in a lymph node, it's recurrence.

67:43

If I see something early, then I'm more apt to think that

67:47

that's likely due to, um, recurrence,

67:50

especially if the dose is lower.

67:53

Um, but also to look at the margins.

67:56

Remember if I see tumor rising in the margins again,

68:00

then I'm more apt to call that recurrence.

68:02

So these are all nuances that you can use

68:05

to help you separate recurrence from

68:07

post-treatment changes, changes.

68:10

Um, the next one is any format, uh, checklist

68:14

for post-op neck?

68:16

Uh, so the answer is yes.

68:18

Uh, number one, what I do is I try

68:21

to get the pre-treatment studies.

68:23

Number two, I try to figure out what type

68:26

of treatment they've had.

68:28

So I actually like this

68:30

'cause I always like to guess that treatment,

68:32

just whether it's radiation or surgery

68:34

or what type of flat, I just get a joy in that.

68:38

So next thing is I, I try to get the pretreatment,

68:41

figure out where the primary site was, try to figure out

68:44

what treatment they have.

68:46

Then I start to look at the margins

68:48

and then I start to look at the lymph nodes.

68:50

So in my mind, those, that's my approach to this,

68:54

I always try to look at those four or five things.

68:59

Um, thanks Anga, thanks for joining.

69:02

Uh, um, uh, great question. Diffusion kurtosis.

69:06

Um, yeah, when I think of diffusion kurtosis,

69:10

I'm really thinking more DWI or diffusion based sequences.

69:14

So I think kurtosis can be happen, can be helpful,

69:17

but you know, realize kurtosis is basically a bell curve.

69:21

It is, it's a statistical probability.

69:25

And you know, one thing that I read recently is that again,

69:29

as a radiologist, it's impossible for us

69:34

to exclude microscopic disease of tumor.

69:37

We just can't do it. We can't exclude microscopic disease.

69:41

So whether or not we're looking at MR, whether

69:44

or not we're looking at ct, whether

69:47

or not we're looking at diffusion

69:49

or profusion when we see something on imaging,

69:53

what we're actually saying is that we feel

69:56

that the predominant tissue type

70:00

is either post-treatment changes or it's re recurrence.

70:03

We cannot exclude microscopic disease.

70:05

So when we look at the ketosis, what ketosis is doing,

70:10

it is saying that there is a probability

70:12

that there may be some recurrence there,

70:15

but the predominant soft tissue

70:19

is probably gonna be post-treatment changes.

70:22

So that's how I kind of look at ketosis.

70:25

A lot of this is probability

70:27

and I think our referers know

70:29

that we can never ex exclude microscopic disease.

70:33

Um, thank you very much, uh, for this anonymous attendees

70:37

and thanks for staying up so late.

70:39

Um, what's the best imaging modality MRC to your pet?

70:44

Uh, it's a great question.

70:46

Um, I think for me, uh, when I look at, um,

70:52

anything below the soft palate like the larynx,

70:54

the oral cavity, oral pharynx, I tend to use initially CT

70:59

followed by PET ct.

71:01

Um, for the skull base I tend to use MR

71:04

and then followed by PET ct.

71:05

But I will tell you one thing is that

71:10

if I have a patient that has an oral pharynx cancer

71:13

or a soft palate cancer, um,

71:16

or an oral cavity cancer, I am using MR.

71:19

More and I am using profusion based mr.

71:23

Um, and I like to use, um, uh,

71:27

a T one weighted dynamic sequences.

71:29

So I don't necessarily use, you know,

71:32

make quantitative assessments of this blood flow,

71:35

blood volume, et cetera.

71:37

A lot of places do that.

71:39

There was a paper that was written about 30 years ago

71:42

that I still use,

71:43

which is a dynamic gradient echo T one sequences in which

71:47

you inject, uh, uh, uh, uh, contrast.

71:51

You do a bolus injection, uh, a uh, power injector injection

71:55

and then use dynamic grading echo sequences

71:58

and you look for differential enhancement.

72:01

And I found that sequence really helpful

72:02

because the tumors tend

72:04

to have higher enhancement than the post-treatment changes.

72:07

So if I am looking at oral pharynx, oral cavity cancers, um,

72:12

I will use this dynamic gradient echo MR sequence first,

72:16

and then if I'm still not sure, then I'll go on to a pet ct.

72:22

Uh, thank you. Uh, sala, um, how

72:26

many occur necrosis?

72:29

Um, I don't, don't know that question.

72:32

How many occur necrosis and failure postsurgery?

72:35

I need a little bit more clarification on that one.

72:40

Um, thank you shalin.

72:42

Um, what mr.

72:45

CT and PET is still indetermined for ON versus recurrence?

72:48

What follow-up? That's a great question.

72:50

Um, I would probably say,

72:57

uh, let me think about that.

72:59

Um, you know, if something is still indetermined for O

73:04

or N versus recurrence, what followup do you get?

73:08

I would probably end up getting a pet ct, uh,

73:11

in six months to a year.

73:13

So those are sort of rad criteria,

73:15

but I would probably get it within six months to a year

73:19

if there's still clinical suspicion.

73:21

Um, so that's probably what I would recommend for that.

73:24

That's a really good question.

73:25

Um, but that's probably what I would recommend.

73:29

Um, let's see.

73:31

How will the fracture of the mandible affect the structure

73:34

and function of the face?

73:36

Okay,

73:37

Now we, this is in regards to the car crash question.

73:40

Uh, yeah, yeah. Got it. Yeah. Okay.

73:42

Um, so, um, yeah,

73:47

so if you do have mandibular fractures,

73:49

you are gonna have increased uptake on the PET ct.

73:51

So, um, I guess if what you're saying is if someone had a

73:57

reconstruction or they had a head

73:58

and neck cancer, then they were under when a car crashed

74:01

and they had a mandibular fracture, um, then the healing,

74:05

um, you are gonna have increased FDG uptake

74:07

at the side of the fracture.

74:08

I guess so. Um, i, I think

74:11

that way I think it can be confusing, uh,

74:13

if that's what you're asking.

74:15

I hope I got that right. Yeah. When to go for the biopsy.

74:19

Yeah, so that's a great question.

74:21

So first of all, if there's something clinically, if I,

74:24

if there's something clinical o clinically obvious,

74:26

you know, they don't need imaging,

74:28

they should just get the biopsy.

74:29

That's sort of what's referred to as, I think

74:31

that's a RAD four criteria.

74:33

So if something's obvious, just biopsy, um, if I see a, um,

74:39

uh, on serial imaging,

74:41

if I see a focal soft tissue mass along the margins

74:44

of a resection cavity, then those are the ones

74:46

that I would recommend biopsy.

74:48

But on the other hand, you know, you have to make sure

74:51

that it's either clinically palpable

74:53

or it's accessible for percutaneous biopsy.

74:56

Um, also if there's an enlarged lymph node,

74:59

if I see an enlarging lymph node,

75:01

then those are the ones I'm really suspicious for,

75:03

for having recurrent tumor.

75:05

So to answer your question, specifically

75:08

interval enlargement of a mass, either along the

75:11

surgical margin or within the irradiated site

75:14

or an enlarging lymph node, or if you do a pet CT

75:19

and there's a focal area

75:20

of abnormal uptake along the treated site,

75:23

then those are the ones that should go directly to biopsy.

75:30

I think you got through all of those questions, Dr. ee.

75:34

Okay. Alright. Amazing.

75:36

Thank you so much for doing that

75:38

and for your awesome lecture.

75:41

All right. Well thank you. Thanks, uh, we still have

75:42

that 200 people on too, so that was nice of everyone to,

75:45

to stay as long, as long as they did. So thank you.

75:49

Absolutely. And thank you everyone

75:50

for asking all those amazing questions

75:52

and for participating in today's noon conference,

75:55

you can access the recording of today's conference

75:58

and all our previous noon conferences

75:59

by creating a free MRI online account.

76:02

We'll also email out a link to the replay later today.

76:05

Be sure to join us next week on Thursday,

76:07

June 27th at 12:00 PM Eastern, where Dr.

76:11

Donald Resnick will deliver a lectured entitled

76:14

Osteomyelitis, septic Arthritis,

76:16

and Soft Tissue Infection Mechanisms,

76:18

imaging Findings and Complications.

76:20

You could register for that@mriline.com

76:22

and follow us on social media

76:24

for updates on future NOOM conferences.

76:26

Thanks again and have a great day. Bye.