The time window for intravenous thrombolysis with alteplase is 3-4.5 hours, mainly under multimodal imaging assessment, and it has been shown that screening by MRI diffusion imaging, and piezo water image mismatch, enables intravenous thrombolysis in patients with an onset time of 4.5-6 hours or less, without a significant increase in the risk of hemorrhagic transformation, and improves cerebral perfusion and clinical outcomes of patients. In patients with posterior circulation infarction, recent studies have shown that the rate of revascularization with alteplase thrombolysis, which correlates with the length of the thrombus, is in the range of 20%-30% if the thrombus is within 2-3 cm in length. In patients with severe posterior circulation infarction, a combination of intravenous thrombolysis and endovascular therapy should be performed. In patients with unknown onset or post-wake stroke, thrombolysis should be directed under CT or MRI perfusion imaging.