Inclusion Criteria:  Male or female between the ages of 18 and 80; Acute ischemic stroke patients within 4.5-24 hours of stroke onset, with NIHSS scores > 5; Patients with large vessel occlusion including occlusion of the internal carotid artery (ICA) termination or middle cerebral artery (MCA, M1, or M2 segment), and who are scheduled to receive arterial thrombectomy; Complete an assessment with multimodal CT and meet the criteria as follow: penumbra volume > 10ml, infarct core volume < 70ml, mismatch ratio > 1.2; Patients planning to receive arterial thrombectomy treatment; All patients (or guardians of patients) provided written informed consent.  Exclusion Criteria:  Patients with a medical history of atrial fibrillation or atrial flutter, or a 12-lead electrocardiogram at admission, showing atrial flutter or atrial fibrillation; Patients who have received intravenous thrombolysis; Pre-existing functional impairment with an mRS score ≥ 2; With severe comorbidities (e.g. severe cardiopulmonary insufficiency, advanced malignancy with an expected survival of less than 90d); More than 1/3 areas of hypodense ischaemic changes supplied by the middle cerebral artery on baseline CT; Patients with known hypersensitivity or contraindications to the use of tirofiban; Patients with known hypersensitivity or contraindications to the use of contrast agents in multimodal CT/MRI examinations; Pregnant or lactating women; Patients who are currently participating in other clinical trial; Other conditions judged by the investigator to be inappropriate for inclusion in the clinical study.