Intracranial aneurysms are abnormal bulges in the walls of intracranial arteries. According to bulk autopsy reports, the incidence of intracranial aneurysms is 0.2% to 7.9%, but most are unruptured aneurysms, and the annual incidence of ruptured intracranial aneurysms is 10%. According to statistics, the disease can occur at any age, and its peak incidence is between 40 and 60 years old. Once an aneurysm ruptures, the mortality rate is 40% for the first bleeding and 60-70% for the second bleeding. Thirty-five percent of patients who survive the first bleed with conservative treatment will die within a year from another bleed, and 51% will die within 5 years. More than 60% of patients with severe disability or death occur within 1 year after aneurysm bleeding. Therefore, such patients should be clearly diagnosed and treated in time to obtain satisfactory results. 1.Diagnosis of intracranial aneurysm Timely and correct diagnosis, early elimination of the risk of rebleeding is the key to the treatment of intracranial aneurysm; 1.CT and CTA: have high auxiliary diagnostic value; CT can detect the site of subarachnoid hemorrhage, the size of hematoma, the presence of cerebral pressure, hydrocephalus, etc. CTA can clearly show intracranial aneurysm, the diagnosis rate of aneurysm with diameter greater than 2mm reaches 98%. The diagnosis rate for aneurysms larger than 2mm is 98%. Three-dimensional reconstruction can show the geometry of the aneurysm and its relationship with the aneurysm-carrying artery. 2.MRI and MRA: MRI can detect whether there is thrombosis in the aneurysm, and MRA can clearly show the intracranial aneurysm, and the diagnostic rate of aneurysm with diameter greater than 2mm is 98%. It can also clearly show the geometry of the aneurysm and its relationship with the aneurysm-carrying artery by three-dimensional reconstruction. 3.Lumbar puncture: It is the direct evidence to diagnose SAH after intracranial aneurysm rupture. It has a high diagnostic value for aneurysms with symptoms but not shown by CT or MRI. However, caution should be exercised when releasing cerebrospinal fluid by lumbar puncture to avoid too much and too fast to prevent brain herniation or aneurysm re-rupture and bleeding. 4.Whole brain angiography (DSA): It is currently the “gold standard” for diagnosing intracranial aneurysm. The angiography can not only find out the size, location, shape, number of aneurysms, width of the aneurysm neck, extension direction of the aneurysm neck, presence of collateral vessels and arteriosclerosis, 3-D angiography can also clarify the relationship between the aneurysm and the aneurysm-carrying artery, providing direct and visual evidence for the treatment of intracranial aneurysm. However, whole-brain angiography is an invasive test and there is a certain false-negative rate. Therefore, patients with bleeding who have negative first angiography need to have DSA again 1 to 2 months after bleeding, including internal and external carotid arteries and vertebral arteries. II. Treatment of intracranial aneurysm Aneurysm is a disease with a very high mortality and disability rate among young and middle-aged patients. Once diagnosed, the necessary surgical treatment must be given urgently. The causes: 1. In the acute stage, hemorrhage stimulates the blood vessels at the base or surface of the brain causing cerebral vasospasm, which in turn leads to cerebral infarction and brain damage manifestations such as increased impairment of consciousness, hemiparesis and aphasia. 2. The rebleeding rate of such patients is about 20% within 2 weeks, which makes the patient’s condition deteriorate and even leads to death. The aim of surgical treatment is to remove the cause of the disease and strive to prevent the aneurysm from rupture again. It includes open aneurysm clamping by micro-neurosurgery and intracapsular embolization of aneurysms by endovascular neurosurgery or a combination of the two. Craniotomy aneurysm clamping: The patient is under general anesthesia, the scalp is incised, the corresponding part of the skull is removed, then the brain tissue gap is separated, the aneurysm is found and the neck is separated, the aneurysm neck is clamped with aneurysm clamps, and then the skull is repositioned to achieve the purpose of aneurysm treatment. Endovascular treatment of intracranial aneurysm: Under general anesthesia or local anesthesia, the patient undergoes femoral artery puncture and delivers a microcatheter into the aneurysm cavity through the vascular system to occlude the aneurysm with microspring coils, medical adhesive and other materials, thus preventing the aneurysm from rupture and bleeding and recurrence and achieving the purpose of cure. Currently some European and American countries have adopted endovascular treatment as the preferred method for treating intracranial aneurysms. Endovascular treatment can also be effective for patients who are difficult to open the skull, have poor general condition to tolerate surgery or in the acute stage of bleeding. In addition, endovascular treatment of intracranial aneurysms has the outstanding advantages of less trauma, less pain, lower risk and higher success rate, which is widely accepted by patients.