Angiographic architecture of intracranial vascular malformations and fistulas--pretherapeutic aspects.

The authors describe the angio-architecture of intracranial vascular malformations. Several patterns can be identified thanks to the intracranial superselective angiograms that can now be performed. Schematically, the following features can be seen: direct arterial supply, indirect arterial supply, flow-related arterial ectasia (aneurysm), dysplastic aneurysm, direct arteriovenous fistula, intralesional arterial ectasia (aneurysm), intralesional venous ectasia (aneurysm), venous ectasia. Each of these elementary arrangements are illustrated and their clinical significance outlined whenever possible. Finally, the dural AVM drainage into the cortical venous system serves as an almost experimental model for the appreciation of the role played by the venous congestive phenomenon in brain AVM symptoms.