0:00

This is a patient in the 40s who developed

0:03

a myelopathy. What we see is the T1-weighted, T2,

0:07

and STIR images, showing cord expansion,

0:10

as well as abnormal cord signal intensity.

0:14

Based on these images alone,

0:15

again, we would be in a differential

0:17

diagnosis of longitudinally,

0:20

extensive demyelination versus an infectious

0:23

inflammatory etiology.

0:25

And we would look towards the post-gadolinium

0:28

enhanced scan to try to help us in excluding a

0:31

neoplasm or for our differential diagnosis.

0:35

On the post-gadolinium enhanced images,

0:39

you see that there is contrast enhancement

0:42

within the spinal cord

0:45

extending into the thoracic region.

0:49

However, what's different about this case from the other

0:52

cases of demyelination or neoplasm is that there

0:57

is enhancement on the surface of the

1:00

spinal cord, which is relatively dramatic.

1:03

This bright signal intensity does not represent

1:08

the fat. It's fat down here,

1:12

but up here at the C6-7 level,

1:16

it's contrast enhancement on the

1:18

surface of the spinal cord.

1:20

Typically, we do fat-suppressed post-gadolinium enhanced

1:24

pulse sequences to eliminate the possibility

1:26

that epidural fat would simulate

1:31

contrast enhancement.

1:33

Let's look at the post-gadolinium axial images.

1:39

So as we proceed downward,

1:42

we see the area of contrast enhancement in the

1:48

thecal sac, which is different than that

1:51

of the epidural fat. Let me point that out.

1:55

Posteriorly, here is the epidural fat.

2:01

However, on the post-gadolinium enhanced scans,

2:04

you see here something on the surface,

2:07

the posterior surface of the spinal cord,

2:10

which is gadolinium enhancement.

2:14

Let's look at a few other sections

2:16

to see whether you can see that.

2:18

So at this level,

2:20

we now see enhancement both within the spinal

2:23

cord, as well as on the surface of the spinal

2:27

cord with a minimal amount of epidural fat.

2:32

Cord.

2:34

Surface of cord.

2:36

Epidural fat.

2:37

Posterior column enhancement, as well as

2:40

surface of the spinal cord.

2:42

I'm going to blow this up just a little bit more.

2:46

So I'm looking at is on the surface of the

2:49

spinal cord. That would be decidedly uncommon in

2:53

a tumor and also would be uncommon

2:57

in most infections. In this case,

3:00

the etiology is a lesion which affects the peel

3:04

surface of the spinal cord and then

3:06

infiltrates into the spinal cord.

3:09

And this is fairly characteristic of

3:12

sarcoidosis. So just as in the brain,

3:16

where we see it extending into the PIA,

3:19

and then from there you get edema and secondary

3:22

cortical involvement with sarcoidosis.

3:26

So too,

3:27

is sarcoidosis found on the surface of the spinal cord,

3:32

then growing into the spinal cord from the PIAL surface.

3:36

Here, we have a lesion which is entirely intramedullary

3:40

where we don't see that PIAL involvement,

3:42

which is just to point out that, occasionally,

3:45

sarcoidosis will affect the cord primarily.

3:49

Most of the time it's a meningeal process.

3:53

Let me see whether there are any more

3:56

axial scans that point this out.

3:58

So here we have

4:00

axial scans through the intramedullary

4:02

portion of the sarcoidosis disease.

4:05

But the presence of that superficial enhancement

4:09

is useful in suggesting sarcoidosis differential

4:13

diagnosis would include subarachnoid seeding

4:16

of neoplasm such as medulloblastoma.

4:19

But that's less likely to infiltrate the

4:21

cord secondarily than sarcoidosis.