Inclusion Criteria:  18-75 years old; At least one unruptured intracranial aneurysm was found by CTA; No relevant symptoms, receiving non-operative and conservative observation treatment; Signing the informed consent.  Exclusion Criteria:  Other cerebrovascular structural lesions (such as cerebrovascular malformation and arteriovenous fistula) or craniocerebral tumors; Fusiform or dissecting aneurysms; Traumatic, mycotic and atrial myxoma associated aneurysms; Suffering from systemic connective tissue diseases, such as polycystic kidney disease; Expectant survival of no more than 3 years due to other diseases or poor general conditions; Patients refuse to follow up or cannot communicate with them due to mental diseases; Pregnant women or participating in other aneurysm related studies.