A total of 177 AIS patients within 9 h of symptom onsetwere enrolled. Among these patients, 36 patients (20.3%) be performed with randomized intravenously (n=18, Fig 3) or intra-arterial (n=18, Fig 2) tPA based on multi-MRI findings (50%). The rate of independence (mRS 0-1) in 3 months in MRI-selected intra-arterial tPA group was 55.6%, the IV group only was 44.4%, but difference showed no significance (p=0.739). Recanalization rate in IA tPA group was 50%, that in IV tPA was 27.8%, but no-significantly. (Fig 4) The rate of sICH in intra-arterial tPA group was 2/18 (11.1%), the IV group was 1/18 example (5.6%), but no significance (p=0.603). Patients given IV tPA were treated significantly earlier than intra-arterial (300 min Vs 265 min, p=0.018; Fig 5). The direct cost of intra-arterial treatment was significantly more expensive than IV by RMB 9,000 Yuan (p=0.005). This pilot study supports that it is safe and effective to expand the time window for tPA up to 6 hours in patients with tissue at risk as defined by MRI. The intra-arterial approach shows the trend to more effective, but need to enlarge the sample to further study.