AVM

1-The most common vascular lesion.

    80% before the end of the 4th decades.

    20% below 20 years.

2-Site:

    90% supra tentorial.

    10% infra tentorial.

3-It could contain calcium and if it takes contrast, it cause serpigenous (worm like) enhancement.

4-MRI:

-T1---as a signal void lesion in all pulse sequences before and after enhancement.

-T2--- you could see many areas in between vessels with hyper intensity which is due to gliosis and ischemia.

-Flow sensitive technique= make the vessels appear white instead of black.

-One of the vessels sharing AVM could form an aneurysm.

A CT scan of the head that demonstrates a left occipital arteriovenous malformation (AVM), with multiple calcified phleboliths and numerous hyperattenuating vascular channels.

A sagittal T1-weighted MRI demonstrating a large occipital arteriovenous malformation (AVM) with parasagittal flow voids.

A diffusion-weighted MRI showing a lack of signal intensity associated with an arteriovenous malformation (AVM).

A lateral left carotid angiogram demonstrating a mixed pial-dural arteriovenous malformation (AVM). Arterial and occipital arterial feeders extend to the nidus via distal branches of the middle cerebral artery.