ACOART Intracranial ISR Pilot:Intracranial DCB in the Treatment of Intracranial In-stent Restenosis

Inclusion Criteria: * 18 to 80 years of age * Confirmed by DSA: in-stent restenosis (ISR) at intracranial segment of internal carotid artery, middle cerebral artery, basilar artery and vertebral artery; ISR is defined as \>50% stenosis within or immediately adjacent (within 5 mm) of the implanted stent and \>20% absolute luminal loss * presence of ISR associated ischemic stroke or transient ischemic attacks even with medical treatment and strict control of risk factor * asymptomatic ISR with severe hypoperfusion in the ISR territories, confirmed by a cerebral blood flow decrease of ≥30% when compared with the perfusion on the contralateral side for anterior circulation lesions or the anterior circulation territory for posterior circulation lesions on CT perfusion, and/or by an American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) Collateral Flow Grading System score \<3 on DSA. * the diameter of target vessel is 2.0-4.5mm * there is only one intracranial ISR lesion per subject * baseline mRS score ≤2 * Voluntarily participate in this study and sign the informed consent form Exclusion Criteria: * Patients with stroke within 2 weeks before procedure; * any history of brain parenchyma or other intracranial subarachnoid, subdural or extradural hemorrhage in the past 30 days. * Those who have received thrombolysis within 24 hours before procedure; * Deterioration of neurological function within 24 hours before procedure (defined as NIHSS score increased by ≥ 4 points over the baseline) * patients with thrombus in target vessels. * in addition to ISR lesions, there are other primary intracranial lesions that need endovascular treatment. * Major surgery (including open femoral, aortic or carotid artery surgery) is planned within the past 30 days or within 90 days. * patients with renal artery, iliac artery and cardiac coronary artery requiring simultaneous intervention. * Combined with intracranial tumors, aneurysms or intracranial arteriovenous malformations. * Cardiac stroke or potential cardiogenic thromboembolism, with any of the following cardiogenic embolism causes: chronic or paroxysmal atrial fibrillation, mitral valve stenosis, mechanical valves, endocarditis, intracardiac thrombus or implant, dilated cardiomyopathy, spontaneous acoustic imaging of the left atrium; * patients with myocardial infarction within 6 weeks before procedure. * those who cannot tolerate general anesthesia due to insufficiency of heart, lung and other important organs. * patients with known severe hepatic and renal dysfunction. * patients with hemoglobin \< 100g / L, platelet count \< 100,000 / mm3, INR \> 1.5or with uncorrectable factors leading to bleeding. * patients who cannot receive dual antiplatelet therapy due to existing diseases or who are tested to be tolerant to dual antiplatelet therapy. * Patients with known severe allergies or contraindications to heparin, paclitaxel, contrast agents and other related intravascular treatment drugs * current alcohol or drug abuse, uncontrolled severe hypertension (systolic blood pressure \> 180mmHg or diastolic blood pressure \> 110mmHg). * Life expectancy \< 1 year. * pregnant or lactating women. * patients who are unable to complete follow-up due to cognitive, emotional disorders or mental illness. * Patients who are participating in other drug/device clinical trials and have not completed all follow-ups required by the programme; * According to the judgement of the investigator, other situations that are not suitable for enrollment