SeQuent ® Please CIS for the Treatment of INtracranial Atherosclerotic Stenosis

Inclusion Criteria: 1. Aged 18 to 80 years old (including boundary value), gender is not limited; 2. The target lesion of the patient is a symptomatic intracranial atherosclerotic stenosis lesion (for part A only) or restenosis lesions after interventional therapy (for part B only); 3. Symptomatic intracranial arterial stenosis (intracranial segment of internal carotid artery (Petrous segment and above), middle cerebral artery, intracranial segment of vertebral artery, basilar artery, etc.) within 6 months, the degree of stenosis of the diseased artery is between 70% and 99% (WASID method); 4. Patients with symptoms occurring more than once (symptoms refer to stroke or transient ischemic attacks) after intensive drug therapy of internal medicine (including antiplatelet therapy, antihypertensive therapy, hypoglycemic therapy and lipid-lowering therapy); 5. The intracranial arterial stenosis lesion to be treated is a single lesion; 6. Patients with at least 1 risk factor for intracranial atherosclerotic plaque, including previous or existing hypertension, hyperlipidemia, diabetes, smoking; 7. Preoperative mRS ≤ 2, and NIHSS≤8; 8. Patients whose life expectancy is greater than 12 months as assessed by the investigator. 9. Patients or their guardians can understand the trial purpose, voluntarily participate in and sign the informed consent form, and can accept follow-up visits. Exclusion Criteria: 1. Severe calcification in the target vessel, severe distortion of the target vessel or anatomical factors that make it hard for interventional devices to be in place; 2. Ischemic symptoms are only associated with branch events; 3. Severe stenosis or occlusion of tandem extracranial or intracranial vessels at the proximal or distal end of the target vessel; 4. Angioplasty or stenting procedures is planned for extracranial vascular lesions with tandem intracranial vessels; 5. History of endarterectomy in the extracranial segment of carotid artery and vertebral artery within 30 days; 6. The target vessel has previously been treated with stenting or angioplasty or other mechanical devices (for Part A only); 7. Acute or subacute intraluminal thrombosis is found in the target vessel; 8. Patients with intracranial stenosis combined with aneurysm, intracranial tumor or intracranial vascular malformation, or intracranial arterial spasm without significant stenosis; 9. Intracranial hemorrhage (cerebral intraparenchymal hemorrhage, massive subarachnoid hemorrhage, and subdural/epidural hemorrhage) within 3 months; 10. There are cardiogenic stroke or risk factors that may contribute to cardioembolism, such as fibrillation, left ventricular thrombosis or myocardial infarction within 6 weeks,; 11. Patients with abnormal coagulation function or bleeding tendency (e.g., international normalized ratio (INR) \> 1.5); 12. Patients with known hypersensitivity to iodine contrast medium, paclitaxel, or iopromide; 13. Patients who are participating in clinical trials of other drugs or devices; 14. Other conditions that the investigator deems the patient unsuitable for enrollment.