0:00

Okay, Dr. Schupeck, this is a weird one.

0:03

This is a 62-year-old lady who's had neck pain since

0:07

She had an operation, a decompression, 4 00:00:11,834 --> 00:00:14,513 it looks like, posteriorly, in 2017.

0:14

And this is a study several months later in 2018.

0:20

Now, she had neck pain after the surgery,

0:22

after the decompressive surgery,

0:24

and she had an epidural injection.

0:26

I don't know the exact date of the epidural injection,

0:29

but it is relevant to the findings in this case.

0:32

So we've got a Sagittal T2,

0:34

water-weighted image done on a three tesla,

0:37

a Sagittal non-contrast T1 weighted image,

0:41

and she's got a little retrolisthesis and some

0:44

degenerative spondylosis at C5

0:46

that would hardly rise

0:50

to the interest level of showing a case worldwide

0:54

in a teaching vignette like this.

0:57

There's an abundant amount of granulation

1:00

tissue and scar posteriorly.

1:02

So let's see what they decompressed in the

1:04

back as we go from distal to proximal.

1:09

And it looks like I think it might be easier to look

1:12

at a different sequence to see what's been taken down.

1:15

So they definitely have taken down some

1:17

of the posterior arch structures,

1:19

and it's very busy posteriorly.

1:22

Now, as we scroll through the axial T2.

1:26

And let's do that.

1:28

Keep an eye on the posterior soft tissues.

1:31

I'm sure everybody's looking

1:32

at the cord and the canal,

1:33

as you appropriately should see if anything

1:36

strikes you during that scroll.

1:39

There should be at least one or two things that

1:41

strike you. And this is for the audience.

1:44

And those things are round and bright.

1:49

There's at least one if we keep going,

1:51

maybe another one, we keep going.

1:54

Let's see if there are any others.

1:55

Oh, there are two more.

1:56

So what might that be?

1:58

And in one of them,

1:59

there's a little dimple of low signal intensity

2:02

inside. Let me blow that up.

2:04

That is very typical of an abscess.

2:09

So if we were to look at this with contrast,

2:13

an abscess is a round structure

2:17

with an enhancing wall.

2:19

And the enhancing wall is usually of uniform caliber

2:23

all the way around. It's usually not lumpy,

2:25

bumpy like, say, a tumor.

2:29

And when you have them in the brain,

2:31

sometimes the abscess will be thinner on the

2:34

non-peeled surface. So uniformity is a key.

2:38

And then inside the abscess,

2:40

you would think naturally that an abscess

2:43

is a liquefied structure,

2:45

so it should have liquid inside it.

2:47

So I'll make it blue for liquid,

2:49

since water is kind of blue and it should be bright.

2:53

Unfortunately, that is not always the case.

2:56

And the reason is you have a lot of proteinaceous

2:58

viscous material inside.

3:00

The second reason is you've got a lot of neutrophils,

3:04

which generate peroxidases and

3:07

other paramagnetic species,

3:10

so it actually drives the signal intensity

3:12

within the abscess down.

3:13

So it's not uncommon in an abscess to see some

3:16

liquefied high signal, but also some really,

3:20

really dark signal in the middle.

3:23

I've got it drawn in gray.

3:25

Maybe I'll pick something that's a little clearer,

3:26

like purple. Here we go.

3:28

Here's some purple representing our dark signal.

3:30

So it's not uncommon to have a

3:32

dimple of dark signal inside.

3:34

And sometimes even the entire abscess isn't bright,

3:38

which is terribly confusing due to a combination of

3:42

protein and the neutrophil products that are made

3:47

inside the abscess that generate these peroxidases.

3:50

So now let's go to the contrast-enhanced MRI.

3:54

And I've got a subtracted one right here.

3:57

I think the subtracted one really shows these ring

4:01

like lesions. Here's one of them right here.

4:03

I'm going to make it bigger.

4:04

And indeed, the ring is pretty uniform.

4:08

Now, as the abscess matures,

4:10

and this is especially true in the brain,

4:12

you'll often see a rim of fibrosis around the

4:16

enhancing rim. So you get an enhancing rim,

4:19

then a rim of fibrosis,

4:20

and then even around that you'll have some edema.

4:24

So it's very concentric looking.

4:27

Almost looks like a fried egg.

4:28

Sign of multiple sclerosis. Now,

4:31

that is not as common a phenomenon in the soft

4:34

tissues, but you absolutely do see the ring.

4:37

And there's more than one of them.

4:38

Here's another one, not quite as perfectly round.

4:41

Slightly lumpy, bumpy, but still thin.

4:45

There's a little bump to it right there.

4:47

And now let's look at the T2-weighted image again.

4:51

And I think we'll take the sagittal this time.

4:54

We'll go right to our area of abscess formation,

4:59

which this is,

5:01

and we'll cross-reference it and let's

5:03

see what the signal of it is.

5:05

It's really not all that bright on the standard T2,

5:08

is it? It's kind of gray to bright.

5:10

In keeping with what I discussed earlier,

5:13

the reasons why abscesses are not uniformly bright. Now,

5:18

this one happens to be Mycobacterium abscessus,

5:25

which is a contaminant.

5:27

You find it in doctors' offices.

5:31

It's found in dust.

5:33

It is attributable to less than optimal

5:37

sterile technique and, unfortunately,

5:40

it is a bear to get rid of.

5:41

It does not respond very well to the typical anti-tuberculous antimycobacterial treatments.

5:45

And that's one of the reasons why this lady has had

5:48

this difficulty for quite some time

5:54

with posterior abscesses.

5:58

Now another.

5:59

Ah.

6:00

Another feature of this case that's worth mentioning

6:04

is the multiplicity of the abscesses and the

6:09

fact that this is an indolent organism.

6:12

Indolent organisms like fungi and mycobacteria tend to

6:18

have lower signal intensity in their abscesses than

6:22

the standard pyogenic ones like Staphylococcus aureus.

6:26

So that would be another thing that would

6:27

point you to something that's atypical.

6:29

Plus, this has been going on for quite some time,

6:32

also points to an atypical cause. If the patient had

6:35

Staphylococcus aureus abscesses in the back of the neck,

6:38

they'd be pretty sick. They might have MRSA,

6:41

they might be hospitalized, etc.

6:43

So this is a contaminant.

6:44

I'll put up the Sagittal contrast-enhanced MR one

6:48

more time to compare with the Sagittal T2.

6:52

Let's go to one of our bigger abscesses

6:57

right there. Look how long that thing is.

6:59

Yeah. They could all be connected, couldn't they?

7:02

They probably are connected, yeah.

7:04

See that's the key to any sort of abscess

7:06

treatment is establishment of drainage.

7:09

Because if you have established drainage,

7:12

you can give them any antibiotics you want.

7:14

It's not going to be able to get access to that.

7:16

So that may have been part of the problem,

7:18

trying to get this cleaned up.

7:20

This would have to be treated openly because

7:22

I already had 14 operations.

7:26

But once again, there's no way around it.

7:29

You can give antibiotics all day and night,

7:31

but you're going to have to establish it.

7:33

And probably what's happened

7:34

is they thought all of it,

7:36

and then there's been another little

7:38

thing and receded. Okay,

7:39

so trying to connect all these dots

7:41

are really where the problem is.

7:43

You can see that there are actually two channels here.

7:45

My guess is they're connected somewhere.

7:47

There's one channel in the back, here's,

7:48

another channel in the front,

7:50

and it looks like a pretty long cigar.

7:52

So at any rate,

7:53

this is an atypical infection from a contaminant.

7:56

It's unclear whether this happened as a result

7:59

of surgery or the epidural injection,

8:01

although the epidural injection has been labeled by

8:06

the clinical staff as the culprit in this case.

8:09

And we've pointed out some key features as they

8:12

relate to abscesses. One more closing point.

8:15

I'm sure you all remember out there imagers that

8:17

abscesses are one of the structures that can diffusion

8:21

restrict because of their increased viscosity.

8:24

So don't forget that that can be helpful to you.

8:27

Hematomas can diffusion restrict as well,

8:30

but simple fluid collections do not.

8:32

Let's move on, shall we?

8:33

Yeah. Thanks a lot. I'm not going to sleep tonight.

8:35

All right. Mycobacterium abscessus.