Inclusion Criteria:  The trial subjects should satisfy all the following criteria.  Adults≥19 years Patients who can start endovascular therapy within 12 hours after the symptomatic onset of Ischemic stroke. NIHSS on screening time point ≥ 8 points Patients whose general condition was favorable enough to perform daily activities without the help of others one day prior to the ischemic stroke onset (a person with mRS 0 or 1) Patients whose CTA or MRA confirmed internal carotid artery occlusion and M1 or M2 occlusion of the middle cerebral artery, that are the types of major cerebral artery occlusion that can cause acute cerebral infarction and are subject to endovascular therapy. Patients with early ASPECTS point≥4 (Noncontrast brain cross-section CT or Brain cross-section MRI diffusion weighted imaging) Patients who spontaneously submitted a written informed consent to participation on this clinical study.  Exclusion Criteria:  A patient who meets any one of the conditions below cannot participate in the Clinical trial.  Patients who meet the following exclusion criteria on imaging of endovascular therapy  ① Patients whose occlusion location that can cause an acute ischemic stroke in the CTA (CT angiography) image meets under the following conditions: A. Occlusion of bilateral large artery B. Simultaneous infiltration of anterior and posterior circulation  Patients who have contraindication to contrast media for brain imaging. Patients who are receiving renal replacement therapy such as dialysis due to acute or terminal nephropathy at screening point. Patients who were diagnosed with cancer or received cancer therapy within 6 months at screening or have recurrent or transitional cancer. Patients have high body temperature of 38oC or more and need antibiotic therapy due to medical opinion of infectious disease at screening. Patients who are having pharmacotherapy due to liver diseases such as hepatic cirrhosis, etc. at screening point.  Patients who are pregnant or lactating. However, only a woman who has no possibility of pregnancy can participate in this clinical research.  Woman with child-bearing potential can be defined as the woman who has not had the clear menopause or who has not had surgical treatment that makes pregnancy impossible.  Patients who have participated in other clinical trial within past 6 months at the screening time as a base. However, in case of participation of observatory experiment, the patient can participate in this clinical trial. Patients who are determined unsuitable for participation in this clinical trial due to other reasons