arachnoid granulation image

[Cece]

http://radiographics.rsna.org/content/2 ... nsion.html

I've been hearing about arachnoid granulations since 2010 but never saw an image of them before. Arachnoid granulations are little buds where cerebrospinal fluid drains into the venous sinuses.

Here's the full article, it's on cerebral venous thrombosis. http://radiographics.rsna.org/content/2 ... 1/S19.full

Although arachnoid granulations are a normal anatomic structure, if they are large and appear in the dominant sinus or only in the transverse sinus, they could cause venous obstruction and lead to symptoms of venous hypertension

[HappyPoet]

Thanks, Cece.
Also interesting to see the two septa in the R-TS which show up nicely in the enlarged photo. I wonder how common they are.

[Cece]

I hadn't even read that far.

Classic appearance of arachnoid granulations. (a) Photograph from an anatomic dissection of the right transverse sinus demonstrates focal protuberances consistent with arachnoid granulations (arrows). Intrasinus septa (chordae willisii) (arrowheads) also are depicted.

googling chordae willisii gets me this:

Chordae willisii are structures located in the lumen of the superior sagittal sinus (SSS). It is thought that they act as flow-improving structures within the sinuses.

http://www.ncbi.nlm.nih.gov/pubmed/15540923

How could a septum improve the flow?

[HappyPoet]

How could a septum improve the flow?

I don't know, but maybe this will help answer the question:

METHODS: ... The chordae willisii were observed in all examined specimens. Three different types of the cords were found: lamellar, trabecular, and valvelike types. The most common type was the valvelike (mixed) one, which comprised 45.1% of all cords. The chordae willisii were most commonly observed in the parietooccipital region of the SSS.
CONCLUSIONS: Witout disturbing any structural relationships, the use of endoscopy allowed visualization and description of intraluminal structures as they behaved physiologically.

Regarding the photo of the R-TS, did you notice how the top septum seems to be attached to an arachnoid granulation?

[brocktoon]

As someone who looks at MR data all day w/r/t to CCSVI&MS, and TBI, these are very common in the dural, and most neuroradiogists I have asked agree that they are too. But, some can be abnormally large, and mistaken for venous sinus thrombosis, and apepar to get in the way of transverse sinus flow which ultimately goes to the jugulars. Large ones are sometimes linked to headache. We still haven't compared arachnoid granules in normals vs. MS.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2588165/

[Cece]

from brocktoon's link

The growth of arachnoid membrane into the dural sinus (glandulae conglobatae) was first described by Pacchioni2) in 1705. These projections are called arachnoid villi or arachnoid granulation, depending on their size. Arachnoid villi are microscopic, whereas granulation is visible to the naked eye11). They function as a passive filtration system for CSF, providing a pathway from subarachnoid space into the venous system. Arachnoid granulations increase in number and enlarge with age in response to increased CSF pressure from the subarachnoid space and are usually quite conspicuous by 4 years of age.

If CCSVI contributed to increased CSF pressure, which led to increased and enlargened arachnoid granulations, it could circularly worsen the already compromised drainage.

It's interesting to hear from someone with your experience, brocktoon, I'm glad you posted.