Endovascular neurosurgery uses minimally invasive techniques guided by imaging to treat cerebral aneurysms, arteriovenous malformations, tumors, and vasospasm. Clinical trials show benefits to intra-arterial thrombolysis up to 6 hours and mechanical revascularization up to 8 hours after stroke. Endovascular techniques are also used to treat unruptured and ruptured aneurysms using coils, stents and flow diverters to occlude the aneurysm and prevent rebleeding. While effective, complications can include hemorrhage in up to 10% of mechanical thrombectomy cases.