What is a nidus in brain AVM?
Arteriovenous malformations (AVMs) are defects in the vascular system, consisting of tangles of abnormal blood vessels (nidus) in which the feeding arteries are directly connected to a venous drainage network without interposition of a capillary bed.
What is the nidus of AVM and radiology?
The nidus is blood density and therefore usually somewhat hyperdense compared to adjacent brain. Enlarged draining veins may be seen. Although they might be very large in size, they do not cause any mass effect unless they bleed.
Do AVM run in families?
AVM does not usually run in families, but somewhere on the order of 5% of AVMs may be due to autosomal dominant inheritance of a genetic mutation, most commonly hereditary hemorrhagic telangiectasia or the capillary malformation-AVM syndrome.
What is the nidus of an AVM?
On the bottom, an AVM is depicted with large sized shunts connecting the artery to the vein. In this diagram three shunts are depicted. The collection of shunts is called the nidus of the AVM. In reality, in an AVM, hundreds of shunts connect the artery to the vein.
What are AVMs in the brain?
What’s important to realize is that brain AVMs are an abnormal tangle of small vessels (called nidus) which directly connect brain arteries to brain veins, without any capillaries in-between (as should be normally the case).
How is an AVM catheter placed in the brain?
Once in the brain arteries, then the tip of the catheter is carefully placed into the individual shunts of the AVM and one by one they are blocked by introduction of a blocking agent into these shunts. This blocking agent is injected through the catheter.
What are the disadvantages of brain AVM treatment?
Disadvantages include very small but much feared possibility of radiation brain damage and lack of cure immediacy (irradiated AVMs are not cured right away, but slowly shrink over months to years). While the AVM remains “alive”, a risk of rupture remains. Our Role: Brain AVM treatment should only be undertaken in a multidisciplinary fashion.