The goal of this clinical trial is to compare intracranial aneurysm patients. The main question it aims to answer are: Which heparinization regimen is most beneficial to patients during surgery for intracranial aneurysms. Participants will be randomized to different intraoperative heparinization regimens: (i) 50 U/kg intravenous (IV) at 1-h intervals reduced by half to a minimum of 1000 u/h; (ii) 70 U/kg IV at 1-h intervals reduced by half to a minimum of 1000 u/h. MRI will be performed within 72 h after surgery, and the DWI sequence of MRI will be analyzed. If there is a comparison group: Researchers will compare different intraoperative heparinization protocol groups to see which dose of intraoperative heparin has the best prognosis for use.

Inclusion Criteria:

1. Greater than 18 years old, less than 75 years old
2. Patients with unruptured intracranial aneurysm were confirmed by DSA.
3. Coagulation function should be normal in the enrolled patients.

Exclusion Criteria:

1. Dissection aneurysm, blister aneurysm, moyamoya disease or arteriovenous malformation.
2. Previous use of antithrombotic drugs (including anticoagulant or antiplatelet aggregation drugs).

Individual participant data (IPD) will be available to other researchers under the approval of the ethical committee.

the data will be available when summary data are published.