0:00

Let's quickly review where we are in the

0:03

assessment of intradural intramedullary lesions.

0:07

We started off by saying that the most common

0:10

etiology for a cord lesion is spondylomyelopathy,

0:15

that is, cervical spinal stenosis or thoracic spinal

0:18

stenosis leading to cord injury.

0:20

Let me just comment about the etiology of the

0:23

cord injury with spondylomyelopathy.

0:26

It's kind of unclear where the cord injury is

0:29

from direct traumatic compression by the

0:33

degenerative change by stretch injury in which

0:37

the cord is fixed by the spinal stenosis and

0:40

then through the activity of the neck,

0:42

you stretch that cord and injure it on

0:45

that basis, or a vascular etiology.

0:49

Even among the vascular etiologies,

0:51

some people say that it is a venous outflow

0:54

ischemic injury to the spinal cord as opposed to

0:58

an arterial injury to the spinal cord from

1:00

compression of the anterior and posterior spinal

1:03

arteries or the small arteries in the spinal cord.

1:07

However, it's pretty uncommon for us to see a spinal

1:11

cord infarct from spinal stenosis.

1:14

That would be very unusual.

1:16

The second category that we talked

1:18

about were neoplastic lesions,

1:19

and we went through various histologies.

1:22

We then just saw multiple cases of demyelinating

1:25

disorders, and I want to review that quickly.

1:28

So the most common of the demyelinating disorders

1:33

in the spinal cord will be multiple sclerosis,

1:36

this far outweighs neuromyelitis optica.

1:40

So cord lesions associated with multiple sclerosis,

1:43

which is the most common demyelinating disorder in adults,

1:47

occur in about one-third to one-half of cases.

1:51

throughout the lifetime of the patient.

1:54

And the initial evaluation of the patient with

1:56

multiple sclerosis usually does include brain,

2:00

cervical, and thoracic spine.

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Please do not recommend evaluation of the lumbar

2:05

spine since MS does not affect the nerve roots.

2:10

For multiple sclerosis,

2:12

we are mostly focusing on our STIR and T2

2:16

weighted images because demyelinating plaques

2:19

in the cord, just like in the brain,

2:21

may or may not show contrast enhancement.

2:24

When we see demyelination in the spinal

2:27

cord with short segment lesions,

2:29

we usually recommend to check the brain,

2:32

in those cases, to exclude periventricular,

2:36

subcortical, or infratentorial lesions,

2:39

which are the other manifestations of

2:41

dissemination in space by McDonald criteria.

2:45

Here is our patient who has upper extremity

2:47

weakness and has a stereotypical lesion

2:50

associated with multiple sclerosis, that is,

2:53

a short segment lesion

2:56

that is located in the posterior

2:58

aspect of the spinal cord.

3:00

MS does favor the posterior columns.

3:05

which may or may not be associated

3:07

with contrast enhancement.

3:10

And on the axial scan, we see that it is a

3:13

small lesion as favoring, in this case,

3:16

the posterior aspect of the spinal cord.

3:19

There likely is another lesion down below.

3:23

Multiple sclerosis of the cervical spinal cord.

3:27

We would recommend getting an MRI of

3:29

the brain and the MRI of the brain.

3:32

We see that this patient has periventricular

3:34

lesions, as well as a lesion in the left internal

3:37

capsule. And more importantly,

3:40

we see a small lesion in the subcortical white

3:44

matter which is showing contrast enhancement.

3:49

Therefore, dissemination in time.

3:52

In the lower spinal cord, we see additional

3:55

lesions that are not expanding the spinal cord

3:59

and likely would not show contrast enhancement.

4:02

Transverse myelitis is a manifestation

4:05

of neuromyelitis optica.

4:07

Transverse myelitis should be considered

4:09

a diagnosis clinically,

4:12

but not a specific pathologic diagnosis.

4:17

Transverse myelitis may be caused by any number

4:21

of abnormalities, including neuromyelitis optica,

4:25

but also

4:27

infectious etiologies, as well as ischemic etiologies.

4:32

Why is this case not multiple sclerosis?

4:35

It does not show small lesions,

4:38

short segment lesions.

4:39

It's a longitudinally extensive transverse

4:42

myelitis. By longitudinally extensive,

4:45

we usually say it spans greater than three segments.

4:47

In this case, it's going from cervical even

4:49

into the thoracic spine.

4:51

This might be a manifestation of neuromyelitis optica.

4:55

The next step would be to scan the orbits as

4:58

well as the brain to identify whether or not the

5:00

patient has optic neuritis and the stereotypical

5:04

NMO brain lesions at the area postrema of the

5:09

brainstem or along the hypothalamus and

5:13

favoring the periaqueductal and posterior

5:17

fossa structures over the supratentorial structures.

5:21

Here is an example of a patient who

5:24

who has NMO, Neuromyelitis Optica Spectrum disorder,

5:27

NMOSD, we see a patient who has a long segment

5:32

lesion in the spinal cord, going over multiple levels

5:41

That shows contrast enhancement along the left

5:47

lateral aspect of the lesion, with a relatively

5:50

subtle lesion on the T2-weighted scan.

5:53

And in addition, has a bright optic nerve, which is showing

5:59

contrast enhancement,

6:01

compare that with the normal optic nerve on the left side.

6:08

When we have a patient who has transverse

6:11

myelitis and we find no etiologies, remember that

6:15

we have to think about demyelinating disorders,

6:18

ischemic disorders, infectious disorders.

6:20

I should mention autoimmune and

6:22

collagen vascular disorders.

6:24

So things like scleroderma or lupus can cause

6:28

transverse myelitis, as well as vasculitis.

6:32

When all those get ruled out,

6:34

we come to the diagnosis of

6:38

Idiopathic Acquired Transverse Myelitis.

6:40

You'll see the acronym IATM

6:42

for Idiopathic Acquired Transverse Myelitis.

6:46

This may be the first manifestation of multiple

6:52

sclerosis in what's called clinically isolated

6:55

syndrome. Or it may occur in and of itself.

6:59

Approximately 30% to 40% of patients

7:02

who present with IATM, ultimately

7:06

down the line, will carry the diagnosis of multiple sclerosis.

7:10

But you can have it just as an isolated

7:13

abnormality, similar to optic neuritis, which

7:17

may occur in an isolated fashion.

7:20

Enhancement with IATM is variable,

7:23

but usually it's not very avid enhancement.