0:00

This is a patient who was 57-year-old male

0:05

that presented with seizure to the emergency room,

0:09

and then a CT of the head revealed

0:13

a slightly hypertense lesion concerning for metastasis.

0:17

This lesion was biopsied

0:19

and was confirmed to be a metastasis from melanoma,

0:23

so he underwent FDG pity for staging.

0:27

We will describe the rest

0:29

of the findings in the body later on,

0:32

but now I want to focus our attention on the brain.

0:36

If you look at the pet alone, you know

0:40

that on the right side you have the expected tracer uptake

0:45

that is distributed along the great matter of the cortex

0:50

and basal ganglia.

0:52

If you noticed in the right frontal lobe, there is, first

0:56

of all, there's an area of diffusely,

0:59

decreased uptake in the cortex,

1:02

but also a focus of intense

1:05

avidity correlating to a hypertense lesion.

1:10

So this was a hemorrhagic metastasis.

1:13

The degree of uptake

1:15

and position of the uptake suggested

1:18

that this was the metastasis

1:20

and there was peripheral bleeding.

1:25

Why do we have decreased cortical uptake is

1:27

because this patient had edema,

1:30

as you can also see it on the CT

1:32

as a diffuse hypo density in the white matter.

1:36

This is how edema is shown on FDG pit

1:39

with diffusely decreased cortical activity.

1:43

Something else that tends to happen in cases

1:47

where there is acute brain insults

1:50

or lesions is

1:53

what is called crossed cerebellar.

1:56

Diastasis, which is demonstrated

1:59

as a decreased tracer uptake in the basal

2:04

ganglia, Ella and contralateral cerebellum.

2:09

This doesn't have a morphologic correlation.

2:13

It's only functional and sometimes it's very subtle.

2:17

So if you don't see in a gray scale,

2:20

but you know that there's something in the brain,

2:22

what I do is change the color scale

2:26

and now it becomes more obvious.

2:29

Notice how we can see a very faint uptake

2:33

in ring-like with peripheral uptake

2:36

surrounding the metastasis.

2:39

So these were two sides of disease in this patient.

2:45

So what is this phenomenon?

2:46

This is a depression in function and metabolism

2:50

because of a contralateral

2:52

focal sial lesion.

2:55

And it could be a met, but it could also be an

2:58

Infarct.

3:00

These outside of the acuity phase,

3:03

the functionality could recover.

3:07

If we look at it in coronal view,

3:09

we can also appreciate the differences in the degree

3:13

of uptake in the cerebellum from the cross.

3:18

The.

FDG Case: Brain Metastasis

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0:00

This is a patient who was 57-year-old male

0:05

that presented with seizure to the emergency room,

0:09

and then a CT of the head revealed

0:13

a slightly hypertense lesion concerning for metastasis.

0:17

This lesion was biopsied

0:19

and was confirmed to be a metastasis from melanoma,

0:23

so he underwent FDG pity for staging.

0:27

We will describe the rest

0:29

of the findings in the body later on,

0:32

but now I want to focus our attention on the brain.

0:36

If you look at the pet alone, you know

0:40

that on the right side you have the expected tracer uptake

0:45

that is distributed along the great matter of the cortex

0:50

and basal ganglia.

0:52

If you noticed in the right frontal lobe, there is, first

0:56

of all, there's an area of diffusely,

0:59

decreased uptake in the cortex,

1:02

but also a focus of intense

1:05

avidity correlating to a hypertense lesion.

1:10

So this was a hemorrhagic metastasis.

1:13

The degree of uptake

1:15

and position of the uptake suggested

1:18

that this was the metastasis

1:20

and there was peripheral bleeding.

1:25

Why do we have decreased cortical uptake is

1:27

because this patient had edema,

1:30

as you can also see it on the CT

1:32

as a diffuse hypo density in the white matter.

1:36

This is how edema is shown on FDG pit

1:39

with diffusely decreased cortical activity.

1:43

Something else that tends to happen in cases

1:47

where there is acute brain insults

1:50

or lesions is

1:53

what is called crossed cerebellar.

1:56

Diastasis, which is demonstrated

1:59

as a decreased tracer uptake in the basal

2:04

ganglia, Ella and contralateral cerebellum.

2:09

This doesn't have a morphologic correlation.

2:13

It's only functional and sometimes it's very subtle.

2:17

So if you don't see in a gray scale,

2:20

but you know that there's something in the brain,

2:22

what I do is change the color scale

2:26

and now it becomes more obvious.

2:29

Notice how we can see a very faint uptake

2:33

in ring-like with peripheral uptake

2:36

surrounding the metastasis.

2:39

So these were two sides of disease in this patient.

2:45

So what is this phenomenon?

2:46

This is a depression in function and metabolism

2:50

because of a contralateral

2:52

focal sial lesion.

2:55

And it could be a met, but it could also be an

2:58

Infarct.

3:00

These outside of the acuity phase,

3:03

the functionality could recover.

3:07

If we look at it in coronal view,

3:09

we can also appreciate the differences in the degree

3:13

of uptake in the cerebellum from the cross.

3:18

The.

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: Brain Metastasis