0:01

Although we took a little side trip on the signal

0:04

intensity characteristics of

0:06

interparenchymal hematomas, we're still in scenario three,

0:10

which is the worst headache of one's life.

0:13

One of the other entities that may cause a

0:16

thunderclap, acute, abrupt headache is reversible

0:20

cerebral vasoconstriction syndrome, or RCVS.

0:25

Patients with RCVS develop a severe headache.

0:29

It may be associated with vasoactive drugs

0:31

that they may be taking for hypertension,

0:34

for example, or in the postpartum setting with

0:37

women who may have elevation of blood pressure.

0:40

Risk factors include migraineurs or patients

0:43

who may have dissection of the vessels,

0:45

or cannabis use—actually, marijuana use.

0:48

Normally, we would evaluate these

0:50

patients with a non-contrast CT scan.

0:52

The vast majority of these patients

0:55

do not show subarachnoid hemorrhage.

0:58

Rarely, you will see a little bit of blood products,

1:00

but the vast majority do not show subarachnoid hemorrhage.

1:04

And yet, because of that thunderclap nature

1:07

of the headache, they will often get a CTA.

1:10

Certainly, you may also evaluate

1:13

the patient with MRI or MRA.

1:15

And in these instances,

1:17

what you see is vasoconstriction.

1:19

What do we mean by vasoconstriction?

1:21

We're talking about something that looks like vasospasm.

1:25

Here is an MRA of a patient who presented with

1:29

a thunderclap headache, had a negative CT scan, a negative

1:33

lumbar puncture, did the MRA, and what you see are

1:37

these areas in which the blood vessels are missing.

1:40

This is severe vasospasm in the left

1:43

middle cerebral artery distribution.

1:45

Also found in the posterior cerebral

1:48

artery distribution in this individual.

1:51

So this vasospasm, in and of itself,

1:54

can cause the severe headache.

1:57

Here is an example that has an

1:59

arteriogram from the literature.

2:01

This is from one of my former clinical

2:04

neuroradiology fellows and a colleague at the University

2:07

of Maryland, Dheeraj Gandhi and Mossa-Basha.

2:11

And what you see is a high signal intensity

2:15

in the posterior white matter of the brain.

2:19

This is the pattern that you would normally

2:21

think—well, could this be posterior

2:23

reversible encephalopathy syndrome?

2:25

PRESS.

2:26

And this is RCVS simulating PRESS

2:29

can have the same sort of

2:32

issues related to blood pressure.

2:34

On follow-up examination, it goes away.

2:37

But at the time of the patient's symptomatology,

2:41

you see that the patient had an arteriogram showing

2:44

areas of high-grade stenosis in peripheral vessels,

2:48

indicative of RCVS—Reversible

2:52

Cerebral Vasoconstriction Syndrome.

2:55

The criteria for making this diagnosis are: severe,

2:59

acute headache; usually a uniphasic disease;

3:04

no subarachnoid hemorrhage from an aneurysm; CSF

3:08

normal; but multifocal, segmental cerebral artery

3:12

vasoconstriction or vasospasm demonstrated on catheter

3:15

angiography or via the CTA or MRA, which reverses—

3:20

so it is the "R" (reversible) within 12 weeks of onset.