Spring-ring embolization of cerebral aneurysm: The local dilatation of the normal vessels of the cerebral artery into a sac-like shape is called aneurysm. The aneurysm wall is thinner than the normal vessel wall and is prone to rupture and bleeding, which leads to subarachnoid hemorrhage. Patients mostly present with unbearable headache, which is an acute and critical disease with high mortality rate. Interventional techniques can be used to occlude the aneurysm, followed by medication to control postoperative complications, which can save the patient’s life and avoid craniotomy with less pain. The current 2012 US guidelines recommend interventional treatment of aneurysms that can be embolized as a rule, rather than craniotomy. (Above: CT image of the head of subarachnoid hemorrhage, bottom left: posterior communicating aneurysm, bottom right: posterior communicating aneurysm after spring coil embolization)