Intracranial aneurysm is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. WILLIS®, researched and developed independently by MicroPort NeuroTech is first-of-its-kind product in China indicated for the treatment of intracranial aneurysms. WILLIS® intracranial stent graft system is composed of the stent, delivery system, cobalt-based alloy stent and PTFE graft. Compared with the traditional method of stent-assisted coil embolization treatment, the procedure of vascular reconstruction using WILLIS® effectively shunt the blood flow and keep it off of the aneurysm wall.