Un-ruptured intracranial aneurysm is a complex disease that seriously affects human life and health. At present, the treatment of intracranial aneurysm is divided into interventional treatment and craniotomy clipping, the two treatment methods are different in the intervention effect of aneurysm, for example, the complications of interventional therapy are lower than craniotomy clipping, but the long-term patency rate is lower than craniotomy clipping, and there is no standard of treatment in different parts of aneurysm in our country, the choice of intervention measures of un-ruptured aneurysm is different in different clinical centers; on the other hand, there are serious problems in the treatment of aneurysms, because without the relevant guidelines of diagnosis and treatment of intracranial aneurysms, different clinical centers will cause excessive treatment of un-ruptured aneurysms, not only bring unreasonable utilization of medical resources, but also cause the subject's life and property to be threatened.

The patients with un-ruptured intracranial aneurysm(estimated sample number over 1500) were included in prospective cohort study, after clipping and intervention operation, setting fixed time for postoperative follow-up, the clinical data and image data were recorded, the safety, efficacy and economic benefits of interventional treatment and craniotomy clipping were compared, providing strategies for the standardized treatment of un-ruptured intracranial aneurysms.

For this study,investigators consulted and hired professionals and experts about data collection, data and methodology,including Data Monitoring Committee, Data Management Committee, Progect Academic Committee, Executive Group, Project Manager, Project Statistician,Technical Support Center. investigators have a scientific regulations for this project. Project Manager and Executive Group: To ensure the successfully implementation of this project, including charging the daily operations of the study in 20 different research hospitals, organizing the monthly meeting to consider issures raised during the monthly progress of the study, liaising with the steering committee,the data management centre and statistical centre. Data management Committee: To be responsible for setting up and maintain the Electronic Data Capture (EDC) System according to the papera Case Report Form(pCRF) designed by principal investigators. To collect and save the pCRF coming from sub-centers. To entry the data into EDC system and keep the same with CRF. To organize training for the investigators about the rules in filling the EDC and pCRF.To determine the frequency of the Data Management Report and to fed it back to the steering committee every three months. Data Mornitoring Committee: To determine the frequency of the data mornitoring including the source data(Medical records) accuracy, completeness and representativeness comparing the external data(EDC, pCRF) in participanted centers.

To report the results after the mornitoring back to the steering committee about the missing data, non-reported and other problems about the study. To make a Standard Operation Procedure(SOP) from getting data to using data. Academic Committee: To supervise the academic issues including patient recruitment, protocol deviation, adverse events evalutating. To settle down the question and problem in the process of the study. Project Statistician: We cooperate with the statisticians of Medical Research & Biometrics Center National Center for Cardiovascular Diseases, China to get the perfessional statistical report. Technical Support Center:To provide technical support during the process of the study.

Inclusion Criteria:

1. At least one imaging methods( CTA / MRA / DSA ) confirmed un-ruptured intracranial aneurysms, whether have clinical symptoms or not;
2. For multiple aneurysms, regardless of previous treatment, the requirement for treatment interval should > 6 months.
3. The patient has the autonomous life ability, the scores of MRS≤ 3 points;
4. The subjects age > 14 years
5. subjects or family members agree to sign informed consent.

Exclusion Criteria:

1. Intracranial aneurysms and with 30 days of unexplained subarachnoid hemorrhage;
2. Subjects with other intracranial vascular malformations, such as AVM, AVF, etc.;
3. Subjects with malignant tumors in the intracranial or other parts of the body;
4. Fusiform, traumatic, bacterial or dissecting aneurysm;
5. Subjects with severe mental illness unable to communicate when diagnosing disease;
6. The body condition is poor, the survival time is less than 1 year or poor physical condition, can not tolerate the general anesthesia or aneurysm surgery;
7. Subjects involved in other intracranial aneurysms related clinical research;
8. A patient who received surgical clipping or endovascular treatment at once;
9. Subjects who were not followed up.
10. < 3 mm intracranial aneurysm。

Patients with un-ruptured intracranial aneurysms.

Data are available upon reasonable request. The data supporting this study's findings are available from the Principal Investigator （Chuanzhi Duan） upon reasonable request.