0:00

We're gonna touch on adverse effects from immunotherapy

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that we can see with FDG PET ct

0:07

and I'm gonna show you these with some examples.

0:11

This is a baseline PET CT for a patient

0:14

that was recently diagnosed with metastatic melanoma.

0:17

We have seen this case separately as a

0:22

brain metastasis on FDG pit,

0:25

but now we're gonna discuss other findings as well.

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As you can see in these meat images, there's multiple sites

0:32

of abnormal trace or uptake.

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These are lung metastasis,

0:38

soft tissue metastasis, osseous metastasis,

0:42

small bowel metastasis, as well as multiple hepatic lesions.

0:47

So widely metastatic melanoma.

0:51

This patient started on immunotherapy

0:54

and then on the follow-up exam we can see

0:57

that there has been a very good response

1:00

with almost complete metabolic resolution

1:03

of the hepatic lesions

1:06

and many o of the other lesions in the small bowel

1:09

in the lymph nodes lung have also

1:14

resolved or near nearly resolved.

1:17

There is though, uh, appearance of several

1:22

mediastinal lymph nodes that look very symmetric.

1:26

And here I'm showing more specific view of this patient.

1:31

On the bottom row we have the baseline.

1:33

On the second row we have the first follow up

1:37

after initiating immunotherapy with a combination of drugs

1:42

and then we have a third follow up on maintenance nivolumab.

1:47

I want you to pay attention to these sites

1:51

of uptaking the liver that if you look at the ct,

1:54

have no CT correlate and

1:56

therefore are only FDG Abbott in the follow up.

2:00

The intensity of these lesions have improved.

2:05

Some of them are barely seen.

2:07

It's probably all background liver,

2:09

but we can now identify several hypodense lesions.

2:12

But these are not new lesions.

2:14

These are treated metastasis in the liver.

2:17

And in this next follow up you can see

2:20

how these hypotensive lesions are also resolving.

2:24

So this corresponds with a very nice response to therapy.

2:29

As I mentioned earlier on the first follow up

2:33

after initiation of the therapy,

2:35

there were new findings in the mediastinum

2:38

and the pattern of these resembles that

2:42

of sarcoidosis.

2:44

And this is a great mimicker

2:47

that now we see very often in patients

2:49

that undergo immunotherapy.

2:52

These are reactive lymph nodes.

2:54

They don't represent new metastatic disease

2:59

Things that can help us troubleshoot.

3:01

The interpretation of these cases are one,

3:04

if these findings were absent at baseline

3:08

and two, always double check when was the therapy started

3:13

and what is the relationship in time between the initiation

3:16

of the therapy and this pet ct.

3:19

Obviously these patients will have multiple follow ups

3:22

so the this can also be reevaluated in the subsequent study.

3:28

In this case it did not present much of a challenge,

3:33

but some cases, for instance, of a nonsmall cell lung cancer

3:38

with novel involvement,

3:40

this can represent a true diagnostic challenge.

3:44

Even though these most commonly happens in the chest,

3:48

in the mediastinum,

3:49

they can also happen in other lymph nodes of the body.

3:53

Another thing that can help us, uh, differentiate the two

3:57

would be that if we looked at these lymph nodes,

4:00

they would be more often than not our normal in size.

4:05

The second follow up

4:06

for this patient once he was on maintenance nivolumab,

4:10

was a diffuse uptake in the lungs.

4:14

We have seen on the prior videos

4:19

that uh, normally lungs do not have FDG uptake

4:23

because they're mostly air.

4:26

But look at this case how you can see

4:28

that there is diffuse increased tracer uptake in the lungs.

4:32

This focus now on the chest, the bottom,

4:36

we have the baseline pit where it showed

4:38

that there was a lung metastasis.

4:41

Then the first follow-up showed

4:43

that this lung lesion had decreased in size

4:46

and also degree of trace or uptake.

4:47

And we here we can see those lymph nodes

4:50

that we mentioned earlier.

4:52

On the maintenance nivolumab though we have new findings in

4:56

the lung as demonstrated

4:58

by diffuse ground glass opacities in both lungs

5:02

and diffuse tracer uptake.

5:05

This is immune checkpoint related pneumonitis

5:09

and it's also a common side effect.

5:12

This is important to be communicated to the clinician

5:16

because they might need

5:18

to start the steroids on this patient.

5:20

Obviously check for symptoms,

5:23

but also if reactions are very severe,

5:28

they might need to consider a stopping therapy.

5:32

This is, uh, a separate case also

5:35

of immune checkpoint related pneumonitis,

5:38

but here look at the pattern of pneumonitis.

5:43

In this case, this is a bronchiolitis pattern.

5:47

Pneumonitis can present like this

5:50

or as diffused ground glasses we have seen earlier,

5:54

but also you can mimic organizing

5:56

Pneumonia, NSIP

5:59

or hypersensitivity pneumonitis.

6:03

So all these things we should keep in mind when reading

6:07

these, these cases, particularly the if they

6:10

represent new findings.

6:12

Another common effect of immunotherapy is development

6:17

of thyroiditis.

6:19

You can see at baseline this patient had a normalized

6:23

thyroid and no tracer uptake.

6:25

And after initiating therapy,

6:28

the thyroid gland now is larger

6:30

and it is also diffusely, FDG avid.

6:34

This patient patients are normally

6:37

biochemical hypothyroid and they may not have any symptoms,

6:42

but it is something that is good to keep an eye on

6:46

and follow up.

6:49

This is another example of immune checkpoint related

6:53

adverse effect, which is colitis.

6:56

This is a metastatic melanoma.

6:59

The primary was in the back

7:01

and the metastasis were mediastinal lymph nodes.

7:03

Here there was no abnormal uptake

7:07

on the left side of the colon.

7:08

However, on the follow up PET had shown progression

7:12

of disease, but also diffused tic along the colon.

7:17

This, uh, was accompanied by, uh,

7:20

GI symptoms on this patient with, uh, diarrhea

7:23

and abdominal pain.

7:26

And these are a couple of examples from the literature.

7:28

You can also develop pancreatitis, which is a more,

7:31

more challenging to detect on pit,

7:34

but it shows, uh,

7:36

increased trace optic diffusely along the pancreatic gland.

7:40

And also on the CI would look for loss

7:44

of loation indicating

7:46

that the gland has increased in size.

7:50

And the other thing that you could detect on FDG

7:55

is hypophysitis.

7:57

I always look for a focal uptake in the hypothesis

8:02

and I raise the suspicion of hypophysitis if the

8:07

uptake in the hypothesis is equal

8:10

or greater than the cortex.

8:13

So in summary, we have reviewed specific patterns

8:17

of response for, uh, seen in immunotherapy.

8:21

We've seen a case of Sarco light reaction

8:23

and we have seen several examples of adv adverse effects

8:27

that are depicted on the FDG PET CT

8:30

that one should be aware of.

8:32

And now we're gonna review the cases separately.