0:00

So this first one was a case of radiation changes following

0:05

treatment for radiation therapy. I believe this section was on larynx,

0:10

I believe, if I, if I recall. Mm-hmm. So, um,

0:13

this first case was an example of a patient that had an early true vocal cord

0:17

carcinoma. It's hard to see actually on the pre-treatment study,

0:21

but when we look at the post-treatment study,

0:23

what we end up seeing is diffuse thickening involving

0:28

the, uh,

0:29

true vocal cords and diffuse thickening involving the bilateral area

0:34

epiglottic fos.

0:35

So one thing that's a little bit unusual is because it's a left true vocal cord

0:40

carcinoma,

0:40

they gave a little bit more radiation therapy on the left than on the right. Um,

0:46

the, the attenuation here is actually low attenuation,

0:49

so there's really no aggressive mass seen. Um,

0:53

obviously you can't di differentiate between recurrent tumor,

0:58

uh, microscopic recurrent tumor and just post-treatment changes.

1:02

So I think if you did say you should always in your report say you can't exclude

1:06

microscopic disease, but these findings are pretty much consistent with,

1:11

um, post-treatment changes. So,

1:15

you know what I wanted to do and um, lemme see if I could bring this up here.

1:20

So following radiation therapy,

1:23

what ends up happening is that the radiation therapy elicits an acute

1:27

inflammatory response and this lasts typically about 24 hours.

1:31

And this is followed by interstitial edema. So after you give radiation therapy,

1:35

there's a lot of edema. There's also disruption in the blood vessels, um,

1:40

and the lymphatics.

1:42

And in approximately four weeks you end up developing fibrosis and this involves

1:46

the connective tissues, the blood vessels, and the lymphatics.

1:49

And oftentimes patients are treated with radiation therapy and chemotherapy.

1:54

So what the chemotherapy does is just, it just sort of exacerbates the changes.

1:59

So on the left here is a pre-treatment image and on the right here is

2:02

post-treatment.

2:04

And you can see after post-treatment you can see skin thickening.

2:07

We can see thickening of the platysma muscle,

2:10

we can see thickening here of the strap muscles.

2:13

Notice the radiation changes and thickening involved in the submandibular

2:17

glands. Here's one area epiglottic fold. Here's the other area. Epiglottic fold.

2:21

See how they're diffusely thickened in their symmetric bilaterally.

2:24

And we can see thickening of the posterior pharyngeal wall and we can see edema

2:28

involving the retro pharyngeal space. Another example here,

2:33

pre-treatment, we can see the free margin of the epiglottis.

2:36

After we give radiation therapy,

2:38

we can see diffuse thickening of the epiglottis and notice a low attenuation

2:42

here. There's low attenuation here and that's more indicative of post-treatment

2:45

changes. Also, look at the submandibular glands.

2:48

We can see that they're thickened, or excuse me,

2:51

they're actually in this case shrunken.

2:53

We can see skin thickening here and reticulation of the subcutaneous fat.

2:57

And look at the thickening of the patal muscle two and compare that to the

3:01

pre-treatment studies. Again,

3:05

pre-treatment versus post-treatment.

3:07

These are those changes that you expect to see.

3:09

We see the diffuse skin thickening, we can see the low attenuation.

3:12

And one of the key things that we look for is, uh, sym symmetry.

3:18

Now what about response? So here's example of what we would like to see.

3:22

So here is a pre-treatment image, a large mass here,

3:25

and we can see complete results after radiation therapy.

3:29

Another example here, d uh,

3:31

large mass here involving the left vem after radiation therapy.

3:35

Look at all the changes here. Diffuse thickening of the free margin,

3:38

the epiglottic colotti thickening of the median gloss of epiglottic fold.

3:44

We can see the radiation sil adenitis, uh,

3:47

characterized by decrease in size of the submandibular glands and,

3:51

and abnormal enhancement.

3:53

So the things that we look for after radiation therapy is that what we would

3:58

like to see is a situation like this where we have a mass on the right side and

4:02

after radiation therapy we see complete resolution.

4:05

See how it's completely shrunk. In this particular case, pre-treatment,

4:09

post-treatment, we still see this persistent mass.

4:12

So what we look for is that another example here,

4:16

this is an example of pre-treatment and after treatment we can still see this

4:21

residual focal enhancing mass. So the way the,

4:24

what we would like to see is either complete resolution such as this

4:29

and it completely vanished.

4:31

Or what we end up looking for is a persistent soft tissue mass in which

4:36

the tumor has not reduced by greater than 50%.

4:40

So those are the things that we look for, um, uh, in order to look to,

4:45

to look at complete response. I think the challenge, um,

4:48

in this case was, uh, because there was a left sided tumor,

4:53

a lot of the patients now are getting higher doses to the side of the tumor.

4:57

So we do see the typical changes where we see the low attenuation.

5:00

It's a little bit thicker on the left than on the right,

5:03

but in general we don't see a, a bulky mass here.

5:06

Rather we see all these changes that we would typically expect to see after

5:10

radiation therapy.

5:12

So let me stop there and do you have any questions at all for that?

5:15

So actually, if we don't have any previous image, we have to look for any,

5:21

if any obvious enhancement, you'll be the recurrence or residue disease.

5:26

If not, if we see any low ation will be just edema for the radiation.

5:32

Yeah, it's more indicative.

5:33

So specifically what we look for is an enlarging mass at the primary site or

5:37

along the margin. So that's the one thing that we look for. And, and,

5:41

and enlarging, if we see a big mass pre-treatment,

5:44

we want to see if that mass completely resolves.

5:47

If there is a lower volume lesion and then after radiation therapy the mass

5:51

starts to up, there's a, a, a mass that's growing at the site of the treatment,

5:57

then that's more that's indicative of recurrent tumor.

6:00

The other thing that we always have to look for too is we also want to evaluate

6:04

the lymph nodes because sometimes you'll see nothing at the

6:08

primary site. But then once we look, uh, more in the neck,

6:13

sometimes we'll have recurrences involving the the, um,

6:17

we will have nodal metastases.