0:00

This is an FDG PET CT done to a gentleman

0:04

that had a squamous cell carcinoma of the base of tongue

0:07

that had undergone, uh, radiation therapy

0:10

and had completed the regimen

0:12

and came back for evaluation of treatment response.

0:17

What I want you to look at is this

0:21

abnormal tracer uptake in the right hemothorax

0:24

that we see in the MIP images as we move the patient.

0:29

And then we're gonna center our attention to the lung.

0:35

So we've said already many times in these uh,

0:40

cores that FVG is a sensitive tracer,

0:43

but not as specific as it can show us areas of malignancy.

0:49

It can also show us physiological processes,

0:52

but also benign things.

0:54

Uh, like in this case, we can see

0:58

multifocal three in bad nodularity

1:01

and patchy opacities in the right lower lobe

1:05

and right middle lobe.

1:07

And these all show increased tracer uptake if we compare it

1:10

to the low uptake that we have in the

1:12

normal lung parenchyma.

1:14

So in this case, it's really important

1:17

to first understand the context of the patient,

1:21

but also look at how the CT findings, uh,

1:25

look like here.

1:28

If you only had the ct,

1:29

you would have no hesitation in saying

1:32

that this looks inflammatory or infectious.

1:35

If you recall, this patient had a left tongue, uh,

1:39

base malignancy and therefore it's more prone to aspiration.

1:45

So this is a case of aspiration pneumonia where the FDG

1:50

corresponds to the areas of opacity in the lung consistent

1:54

with active infection.

1:57

The challenges of this is that sometimes, as you know,

2:02

pneumonia is more consolidative

2:07

or nodular and it may be difficult to discern

2:11

as both will show FDG uptake.

2:14

So looking at the medical records,

2:17

seeing if there are ongoing symptoms,

2:20

and ultimately providing

2:22

with the differential diagnosis will be very helpful

2:25

for the clinician with infection.

2:29

We also expect some degree of reactivity

2:34

in the lymph nodes, so it is common

2:38

to also see mild uptake in the

2:42

laterality of the findings.

2:45

In this case, we have very mild uptake in the right hilum

2:48

and al non stations.

2:50

And obviously this adds another layer

2:55

of complexity when reading cases for,

2:59

for instance, lung malignancy that may also spread

3:03

to the different notations.

FDG Case: Aspiration Pneumonia

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0:00

This is an FDG PET CT done to a gentleman

0:04

that had a squamous cell carcinoma of the base of tongue

0:07

that had undergone, uh, radiation therapy

0:10

and had completed the regimen

0:12

and came back for evaluation of treatment response.

0:17

What I want you to look at is this

0:21

abnormal tracer uptake in the right hemothorax

0:24

that we see in the MIP images as we move the patient.

0:29

And then we're gonna center our attention to the lung.

0:35

So we've said already many times in these uh,

0:40

cores that FVG is a sensitive tracer,

0:43

but not as specific as it can show us areas of malignancy.

0:49

It can also show us physiological processes,

0:52

but also benign things.

0:54

Uh, like in this case, we can see

0:58

multifocal three in bad nodularity

1:01

and patchy opacities in the right lower lobe

1:05

and right middle lobe.

1:07

And these all show increased tracer uptake if we compare it

1:10

to the low uptake that we have in the

1:12

normal lung parenchyma.

1:14

So in this case, it's really important

1:17

to first understand the context of the patient,

1:21

but also look at how the CT findings, uh,

1:25

look like here.

1:28

If you only had the ct,

1:29

you would have no hesitation in saying

1:32

that this looks inflammatory or infectious.

1:35

If you recall, this patient had a left tongue, uh,

1:39

base malignancy and therefore it's more prone to aspiration.

1:45

So this is a case of aspiration pneumonia where the FDG

1:50

corresponds to the areas of opacity in the lung consistent

1:54

with active infection.

1:57

The challenges of this is that sometimes, as you know,

2:02

pneumonia is more consolidative

2:07

or nodular and it may be difficult to discern

2:11

as both will show FDG uptake.

2:14

So looking at the medical records,

2:17

seeing if there are ongoing symptoms,

2:20

and ultimately providing

2:22

with the differential diagnosis will be very helpful

2:25

for the clinician with infection.

2:29

We also expect some degree of reactivity

2:34

in the lymph nodes, so it is common

2:38

to also see mild uptake in the

2:42

laterality of the findings.

2:45

In this case, we have very mild uptake in the right hilum

2:48

and al non stations.

2:50

And obviously this adds another layer

2:55

of complexity when reading cases for,

2:59

for instance, lung malignancy that may also spread

3:03

to the different notations.

Report

Faculty

Elisa Franquet Elia, MD

Assistant Professor of Radiology

UMass Chan Medical School

Lesson

Introduction to PET/CT Imaging

Lesson

FDG Use in PET/CT

Lesson

FDG: Common Pitfalls and Benign Lesions

Lesson

FDG Use in Hematologic Malignancies

Lesson

FDG Use in Lung Cancer

Lesson

FDG Use in Head & Neck Cancer

Lesson

FDG Use in Breast Cancer

Lesson

FDG Use in Immunotherapy

Lesson

DOTATATE Use in PET/CT

Lesson

DOTATATE and FDG Use in Neuroendocrine Tumors

Lesson

PSMA Use in PET/CT

Lesson

PSMA Use in Prostate Cancer

FDG Case: Aspiration Pneumonia