0:01

Aneurysms are a more common source of "worst"

0:04

headache of life and subarachnoid hemorrhage

0:07

than arteriovenous malformations or fistulae.

0:10

Nonetheless, each of them may cause

0:13

subarachnoid hemorrhage and bleed and

0:15

lead to the presentation of headache.

0:18

This was a relatively subtle example of

0:21

a CT scan where we noticed that there

0:24

were multiple areas of calcification.

0:28

And hyperdensity without evidence

0:31

of subarachnoid hemorrhage.

0:33

These multiple little calcifications raise the

0:35

possibility of things like cysticercosis or a

0:39

calcified neoplasm such as oligodendroglioma.

0:44

You could see that there is a little bit

0:46

of midline shift at the level of the septum

0:51

pellucidum, and this lesion had some mass effect.

0:55

The patient was referred for MRI scanning.

1:00

Whoa.

1:01

So here we see on the MRI scan that this

1:06

is a very large arteriovenous malformation.

1:10

We do indeed have mass effect with midline

1:13

shift at the level of the septum pellucidum, but

1:15

it's due to this lesion that has multiple

1:18

flow voids of an arteriovenous malformation.

1:23

And this is the T2-weighted scan.

1:25

Here we have post-gadolinium.

1:28

On the post-gadolinium hand scan,

1:29

you might say, "Well, it's an enhancing lesion.

1:32

Maybe it's a tumor."

1:33

The key here is to identify flow-

1:37

related phase ghosting artifact.

1:40

You notice that there is something that is coursing

1:43

across the plane here, identifying that there

1:47

is vascular flow pulsation from this lesion,

1:52

which is indeed an arteriovenous malformation.

1:56

So, subarachnoid hemorrhage may be

1:59

associated with arteriovenous malformations.

2:02

The rate at which an arteriovenous malformation

2:06

bleeds into the subarachnoid space

2:09

is quoted as 1 to 2% per year and, therefore,

2:13

less than the asymptomatic aneurysm, which

2:17

bleeds at approximately 2 to 3% per year.

2:21

One of the benefits of using MRI for the evaluation

2:25

of an arteriovenous malformation is that if you see

2:28

hemorrhagic products, hemosiderin staining

2:32

associated with the AVM, that suggests that the

2:34

lesion has bled in the past and, therefore, the

2:38

rate of bleeding in the future is higher if it

2:42

has demonstrated previous hemorrhage than if

2:45

it has not demonstrated previous hemorrhage.

2:47

So, this is another example of a

2:50

source of the "worst headache of life."

2:53

Here is an angiogram showing an

2:56

arteriovenous malformation.

2:58

You have the

2:59

sagittal T1-weighted MRI scan.

3:02

When we look at an arteriovenous malformation, we also

3:07

look at the drainage pattern and the size of the lesion.

3:11

And this is because of something known

3:13

as the Spetzler-Martin AVM grading system.

3:18

This is a grading system that tells the surgical

3:23

complication rate or the outcome with surgery

3:27

for arteriovenous malformation. In this

3:30

grading system, there are three components: the

3:34

size of the arteriovenous malformation,

3:39

and whether or not it affects eloquent cortex.

3:42

By that, we mean the motor strip,

3:43

speech areas, etc.

3:46

And the drainage of the lesion—if it's

3:49

less than three centimeters, it gets one point.

3:52

If it's three to six centimeters, it gets two points.

3:54

If it's greater than six centimeters, it gets

3:57

three points.

3:58

If it involves an eloquent area, we give it a point.

4:01

If it has deep drainage, it gets a point.

4:05

If it's superficially draining to superficial veins

4:08

or to the superior sagittal sinus, as opposed

4:11

to deep drainage to the internal cerebral

4:13

vein, straight sinus, or vein of Galen.

4:16

Again, these factors suggest a better

4:19

surgical outcome when the numbers are lower.

4:24

A worse surgical outcome may lead

4:26

the surgeon to suggest trying

4:28

endovascular treatment or even radiation

4:33

treatment for the arteriovenous malformation.