Nosologic concepts distinguish three types of aneurysm of Galen's ampulla: true aneurysms, related aneurysms, false aneurysms, whatever the type the majority of these malformations can be treated by the endovascular approach, frequently the most effective alternative therapy. Experience acquired during treatment of intracerebral arteriovenous angioma allows perfect control of direct, high output arteriovenous fistula by injection of pure isobutyl cyanoacrylate. Occlusion of shunts should be combined with prevention of consequences, that is to say extensive venous thrombosis. Two cases are reported that demonstrate the value of post-embolization heparin therapy.