0:01

The location of the subarachnoid hemorrhage gives

0:04

some indication of the location of the aneurysm.

0:08

If you have hemorrhage that is predominantly in the

0:11

interhemispheric fissure anteriorly, we're going to be

0:14

more concerned with an anterior communicating artery

0:18

or anterior cerebral artery aneurysm.

0:20

If you have hemorrhage that is localized

0:23

to one Sylvian fissure over the other,

0:26

we're gonna be more concerned about a middle

0:28

cerebral artery distribution aneurysm.

0:31

If you have hemorrhage, which is diffuse in the

0:34

basal cisterns, that may be due to a posterior

0:37

communicating artery aneurysm or a distal internal

0:40

carotid artery terminus aneurysm if you have hemorrhage,

0:44

which is predominantly in the posterior fossa.

0:47

Or in the fourth ventricle, we're going to be more

0:50

concerned with a vertebral basilar artery aneurysm.

0:53

Usually, the basilar tip is the most common of

0:56

these, but you can have those that occur

0:58

at the vertebral basilar junction or at the

1:02

posterior inferior cerebellar artery origin.

1:06

The PICA origin, those aneurysms of the PICA,

1:10

which are usually off of the vertebral artery, will

1:13

have hemorrhage that layers more commonly at the

1:16

foramen magnum. Some of the

1:19

aneurysms will burst into the brain.

1:21

Parenchyma.

1:22

ACOM aneurysms probably do this the most commonly,

1:25

and they will burst into medial frontal lobe parenchyma.

1:29

So if you have subarachnoid hemorrhage with medial

1:32

frontal lobe parenchymal hemorrhage, we're going to

1:35

be considering anterior communicating artery aneurysm.

1:39

Middle cerebral artery aneurysms will generally

1:42

cause parenchymal hemorrhage in the adjacent

1:45

temporal lobe, and we already saw a posterior

1:48

communicating artery aneurysm, which involved

1:51

the medial temporal lobe in that case.

1:55

On the left side, there are additional aneurysms,

1:58

the anterior choroidal aneurysm that will

2:01

generally hemorrhage into the choroidal fissure

2:03

and get into the lateral ventricular system.

2:06

So by virtue of these localization

2:08

features, you may be able to identify the.

2:12

Source of the hemorrhage.

2:14

However, usually we're following this

2:16

with a CTA, and with the CTA you're

2:19

going to be able to see the aneurysms.

2:21

In the vast majority of cases, over 90%

2:24

of the cases, it's only if you have multiple

2:27

aneurysms that are visible on the CTA, that the

2:31

hemorrhage will tell you which one of those.

2:33

That bled?

2:34

Was it the right MCA, or was it the

2:36

anterior communicating artery aneurysm?

2:38

And for that reason, the site of the

2:41

subarachnoid hemorrhage is useful.

Localization of Aneurysm with SAH

HIDE

Prev Next

Interactive Transcript

Pro Tip: Click on a word in the transcript to jump to that point in the video