The efficacy and safety of methylprednisolone in acute ischemic stroke patients with large infarct cores (ASPECTS score < 6 or infarct volume ≥50 mL) due to anterior circulation large vessel occlusion have not been clearly established. This is a multi-center, randomized, double-blind, placebo-controlled trial to investigate early combination therapy with methylprednisolone for reperfusion in acute large core infarction.

Inclusion Criteria:

• Age ≥ 18 years.
• The time from onset to randomization was within 12 hours.
• Anterior circulation ischemic stroke was preliminarily determined according to clinical symptoms or imaging examination.
• Occlusion of the intracranial internal carotid artery, the M1- or M2-segment of the middle cerebral artery by confirmed by CT angiography (CTA), MR angiography (MRA), or digital subtraction angiography (DSA).
• Baseline National Institutes of Health Stroke Scale (NIHSS) ≥ 6.
• Baseline Alberta Stroke Program Early CT Score (ASPECTS) < 6 (based on non-contrast CT or MRI) and/or core infarct volume ≥ 50 ml (based on CTP with rCBF < 30%).
• Planned treatment with endovascular thrombectomy (EVT).
• Informed consent obtained from patients or their legal representatives.

Exclusion Criteria:

• Intracranial hemorrhage confirmed by cranial CT or MRI.
• mRS score > 2 before onset.
• Pregnant or lactating women.
• Allergic to contrast agents or glucocorticoids.
• Participating in other clinical trials.
• The artery is tortuous so that the thrombectomy device cannot reach the target vessel.
• Bleeding history (gastrointestinal and urinary tract bleeding) in recent 1 month.
• Chronic hemodialysis and severe renal insufficiency (glomerular filtration rate < 30 ml/min or serum creatinine > 220 umol/L [2.5 mg/ dL]).
• Life expectancy due to any advanced disease < 6 months.
• Follow-up is not expected to be completed.
• Intracranial aneurysm and arteriovenous malformation.
• Brain tumors with imaging mass effect.
• Systemic infectious disease.