Recombinant Human Prourokinase for Acute Ischemic Stroke in the Extended Window Selected by CT-Based Artificial Intelligence

Inclusion Criteria 1. Age ≥18 years. 2. Clinically diagnosed acute ischemic stroke. 3. Time from stroke onset to randomization \>4.5 hours and ≤24 hours. For patients with unknown onset time or wake-up stroke, the estimated onset time will be defined as the midpoint between the last known well time and symptom discovery time. 4. Baseline National Institutes of Health Stroke Scale (NIHSS) score of 4-25. 5. Pre-stroke modified Rankin Scale (mRS) score of 0-1. 6. No planned endovascular treatment at randomization. Patients with large vessel occlusion who are eligible for endovascular treatment must undergo independent evaluation and discussion before study enrollment. Patients who are planned to receive endovascular treatment will not be enrolled. 7. Meeting the CT-AI tissue-window selection criteria: * Predicted ischemic core volume ≤70 mL; * Hypoperfusion-to-core volume ratio \>1.2; * Difference between hypoperfusion and ischemic core volumes ≥10 mL. 8. Written informed consent provided by the participant or their legally authorized representative. Exclusion Criteria 1. Baseline CT showing intracranial hemorrhage, subarachnoid hemorrhage, brain tumor, brain abscess, or other non-ischemic lesions. 2. Baseline CT showing an extensive infarction, severe cerebral edema, or mass effect, or the investigator determines that the risks of intravenous thrombolysis substantially outweigh the potential benefits. 3. Contraindications specified in the prescribing information for recombinant human prourokinase for injection or current intravenous thrombolysis guidelines, other than the extended treatment time window specifically evaluated in this trial, including but not limited to: * Any history of intracranial hemorrhage; * Severe head trauma or stroke, including ischemic stroke, within the previous 3 months; * Recent major surgery or severe trauma; * Active internal bleeding; * Significant coagulation abnormalities; * Platelet count \<100 × 10⁹/L; * Blood pressure that cannot be adequately controlled to meet intravenous thrombolysis requirements despite treatment; * Other conditions associated with substantially increased bleeding risk as determined by the investigator. 4. Pregnancy, breastfeeding, or unwillingness to use effective contraception during the study. 5. Inadequate NCCT image quality for CT-AI analysis or inability of the AI model to generate valid outputs. 6. Participation in another interventional clinical trial within the previous 3 months. 7. Expected survival of less than 3 months. 8. Other conditions considered by the investigator to increase the risk of study treatment or interfere with study participation.