The first purpose of this study is to find out the clinical benefit and risk of oral aspirin for unruptured intracranial aneurysm (small than 7mm) combined with cerebral ischemia in patients in the real world.

The second purpose of this study is to get the prediction model of aneurysm's rupture in patients who has unruptured intracranial aneurysm (small than 7mm) combined with cerebral ischemia , and find out who is suitable for oral aspirin.

The investigators try to collect the information of the patients have unruptured intracranial aneurysm combined with cerebral ischemia when oral aspirin.The characteristics of this study are large sample, multi center and prospective.In the real world, more and more patients are checked out unruptured intracranial aneurysm combined with cerebral ischemia.The investigators can collect the information such as how they use aspirin (dose, frequency, duration of treatment), demographic information, past history, daily life habits, morphological characteristics of the aneurysm, how they use other antithrombotic drugs.The investigators will record whether the aneurysm ruptured and have hemorrhage, ischemic stroke, death, changes in the morphology of aneurysm, MRI permeability image index changes. Finally the investigators will get the clinical benefits and risks of using aspirin and build the prediction model of rupture and hemorrhage for aneurysm, find out who is suitable for oral aspirin.

Inclusion Criteria:

1. has the diagnosis of unruptured intracranial aneurysm (using the CTA/DSA,smaller than 7mm)
2. has the history of TIA or any other diseases of cerebral ischemia
3. older than 18 years old
4. sign the informed consent

Exclusion Criteria:

1. has the history of intracranial aneurysm rupture hemorrhage or has more than one aneurysm untreated
2. has a family history of intracranial aneurysm
3. has AVM，MMD, intracranial tumor, hydrocephalus or intracranial hemorrhage
4. refuse to sign the informed consent
5. allergic to contrast medium

The investigators chose the patiens from the Tiantan hospital and other hospitals that participated in this study.The patients will all have unruptured intracranial aneurysm with the history of cerebral ischemia.