0:00

It's a 56-year-old woman.

0:02

She's having trouble walking.

0:04

Looking at the images,

0:05

no joke.

0:07

Sagittal T1 C+ thoracic,

0:10

sagittal T2 fast spin echo,

0:12

and axial T2 fast spin echo.

0:15

I'm here with my colleague, Dr. Ben Lazar,

0:17

and we're tackling this rather complex case in a series

0:22

of vignettes covering a topic that relates

0:25

to vascular abnormalities of the spine.

0:28

So let's start out with the sagittal T2 fast spin echo.

0:33

Let's scroll a little bit,

0:34

give you a chance to gaze upon the beauty,

0:37

or lack thereof, of these images.

0:40

And then I would ask Dr. Lazar

0:43

to latch on to the finding that suggests a vascular

0:48

problem for this patient, especially on the Sagittal T2.

0:53

So, in the Sagittal T2 sequence,

0:55

if you notice below the surgical site,

0:58

there's a surgical site.

0:59

You'll see these serpigenous dots or lines that are extra

1:05

medullary that course along the ventral and the dorsal

1:08

spinal cord, which would suggest a vascular abnormality.

1:12

The other thing you would note, too,

1:13

is if you look at the spinal cord just

1:16

at the margin of the surgical site,

1:19

you'll see this vague hyperintense signal within the

1:22

spinal cord. These are suggestive of dural AVF,

1:27

which has either been treated successfully

1:29

or unsuccessfully.

1:30

So one possibility is that the echoliosis

1:34

is related to the surgery.

1:35

Another possibility, which I like better,

1:38

is that it's related to the Dural AVF itself.

1:41

And this pattern of venous congestion produces swelling and

1:46

gliosis of the cord and basically results

1:49

in a venous type infarction of the cord.

1:53

So let's talk about this before we get into what's

1:55

going on up here, which is just a hot mess.

1:58

Let's talk about the most common type of dural AVF.

2:02

And we're hammering away at this because radiologists

2:05

miss this again and again and again.

2:07

And on the average,

2:08

an expert radiologist, a master-level radiologist,

2:12

is the fifth one to touch this case after it's

2:15

missed four times, and then it's too late.

2:18

So this is 70% of vascular lesions of the spine,

2:23

and it almost always occurs at the

2:26

level of the heart or below.

2:29

Now,

2:29

it's usually caused by a single radiculomeningeal feeder.

2:33

Occasionally, you have more than one,

2:36

and it results in a fistula between the dural and the

2:39

pial veins, resulting in venous hypertension.

2:42

That is the disease in a nutshell.

2:45

And if the patient has an accelerated,

2:47

a markedly accelerated course,

2:49

it usually means that one of those veins has thrombosed,

2:54

and that leads to subacute necrotizing myelopathy,

2:58

also known as.

2:59

Foix-Alajouanine syndrome, described in 1926.

3:04

As we've said multiple times, these are typically males,

3:08

middle-aged males. This is another woman, unfortunately,

3:11

but middle-aged males with ascending weakness,

3:14

bowel dysfunction, bladder dysfunction, impotence.

3:18

And in fact,

3:20

in some reports, the male-to-female ratio is really high.

3:23

It's like five to one.

3:24

I've seen it as high as seven to one.

3:27

But again,

3:27

this is a woman just sprinting over to the right

3:30

hand side and doing a little scrolling.

3:33

The delicateness of these low-signal areas and

3:37

the fact that they're gray and not jet black

3:41

is indicative of vessels, as opposed to, say,

3:46

fast flow in the subarachnoid space,

3:48

which is a very common pitfall.

3:50

Now, something you pointed out earlier, Ben,

3:52

is that the periphery, the pial surface of the cord,

3:56

is kind of dark. And what's that suggest to you?

4:00

So that suggests one of two things.

4:02

Either the patient has bled from the dural AVF or

4:07

postoperative complication from a subarachnoid hemorrhage,

4:11

essentially hemosiderin lining the pial surface and staining it.

4:15

My personal experience is that clinically,

4:18

they don't show up with subarachnoid hemorrhage very often.

4:21

But the literature says that the subarachnoid hemorrhage

4:24

incidence is pretty high. What is it like?

4:26

What's the percent? About 36%.

4:28

36%. So my experience hasn't been that high.

4:31

But I think a lot of those subarachnoid hemorrhages are

4:34

quiet, they're occult, because it is a venous phenomenon,

4:37

a lower pressure scenario,

4:39

and that leads to this sort of darker appearance

4:42

around the outside of the cord.

4:44

So let's work our way up a little higher and see if we can

4:48

tease out what's happened here where

4:51

they operated on this patient.

4:52

Now,

4:53

somebody read this as multiple arachnoid cysts,

4:57

and I can see why they suggested that there's sort

5:00

of this loculated mass effect back here.

5:04

But what do you think of that diagnosis?

5:06

And I'm going to scroll up there with my axials

5:09

just to give us a little bit better bearing.

5:11

There's some signal in our cord as we escape and go north,

5:14

and that cord is really stuck anteriorly.

5:18

So what do you think some possibilities are besides

5:21

arachnoid cyst, even though we don't have the answer?

5:23

So, given the history of surgery,

5:26

clearly from the surgical changes,

5:28

two things pop in mind almost immediately.

5:29

One would be whether the spinal cord is adhered to the

5:33

ventral or to the posterior aspect of the vertebral bodies,

5:36

or if there's a spinal cord herniation.

5:38

As you can tell, at this level, right at the disc level,

5:43

the spinal cord is inseparable and plastered up against

5:47

the posterior aspect of the vertebral body,

5:49

which is a classic sign of spinal cord herniation.

5:52

Given the surgery, though,

5:53

I think adhesion is also a consideration,

5:56

and that is usually the differential.

5:58

It's usually between those two.

6:00

And when you extract the cord forward,

6:03

you create this void which gets filled with fluid.

6:06

And a lot of times people call these arachnoid cysts.

6:09

It'd be awfully coincidental to have a rare lesion,

6:13

an arachnoid cyst and a dural AVF together in one scenario,

6:19

especially in somebody that's already had an operation.

6:21

So I'm not really sure I like that diagnosis.

6:24

There's also some pulsatile pulsation in here,

6:26

which I don't usually like to see in my arachnoid

6:28

cysts because they're kind of tight.

6:30

You don't have a lot of back and forth motion in them.

6:34

And you pointed out earlier there's also some gliosis,

6:38

a bit more proximally. Now,

6:41

typically the peak location for these is about T seven

6:45

to T nine. Next most common T ten to T twelve.

6:49

And then you get into less common locations.

6:52

L one to L3, T four to t six and L4 to s one.

6:57

There is a high cervical type that occurs in

7:00

the foramen magnum. In my experience,

7:02

I've seen that more commonly with the type two form

7:06

of dural, sorry, vascular anomaly of the cord.

7:11

The so-called glomus type, the dural AVM,

7:14

as opposed to the dural AVF, but they do occur there.

7:17

But that is quite rare.

7:19

So, in summary, we've got somebody that had an operation,

7:23

didn't go well. The cord has been damaged.

7:27

It's thick, it's thin, it's gliotic.

7:29

It's either herniated or adhesive.

7:32

The patient has gliosis below the operative site

7:35

and still has persistent signs of a dural AVF.