Cerebrovascular stenosis 90% whether to put a stent with its stenosis location, collateral circulation and the patient’s own situation, etc., some can not put a stent. 1. Cerebrovascular stenosis location: Although the cerebrovascular stenosis reaches 90%, but the location is remote, such as the middle cerebral artery M3 segment, the anterior cerebral artery A2 segment, etc., it is not suitable for stenting, and need to be treated conservatively with drugs. However, if the middle cerebral artery M1 segment, internal carotid artery severe stenosis, stenting is recommended to prevent stroke. 2. Collateral circulation: Although the cerebrovascular stenosis is severe, if good collateral circulation has been established, stenting can be avoided. 3. Patient’s own condition: If the patient’s basic condition is poor, such as cardiopulmonary insufficiency, even though the cerebrovascular stenosis is severe, it may not be suitable for stenting, and it needs to be treated conservatively with drugs. If 90% of cerebrovascular stenosis is found, it is recommended to consult a doctor as soon as possible, and evaluate whether to perform stenting or conservative treatment under the guidance of a professional doctor.