The study is to explore the molecular mechanisms underlying the occurrence of malignant cerebral edema (cerebral hernia) after large hemispheric infarction. Acute LHI (<=48h) patients that develop cerebral hernia or not within 5 days post-stroke onset, as well as the healthy controls will be studied. The participants will be followed for up to 6 months post stroke-onset, and their modified Rankin Scale (mRS) will be recorded. A mRS score of 0-4 is considered as a favorable outcome while a score of 5-6 as an unfavorable one.

A total of 80 patients with acute large hemispheric infarction (LHI) within 48h after occurrence admitted into NICU of Xuanwu Hospital as well as 40 healthy volunteers will be recruited. The patients' baseline characteristics, treatment and changes of clinical conditions will be recorded, and ICP monitoring (D2-D7 post-stroke), chest X-ray (D2, D7, D14 post-stroke), ECG (D2, D7, D14 post-stroke), cerebral vascular ultrasound, TCD and head MRI (T1WI, T2WI, FLAIR, DWI) on D2 and D14 post-stroke will be performed. Blood samples from both the LHI patients (D2, D4, D7, and D14 post-stroke) and the controls will be analyzed for NEU, TNF-alpha, IL-1b, IL-6, IL-8, IL-17, ICAM-1, VCAM-1, MPO, NE, MMP-9,miRNA, free dsDNA, H3CIT and NETosis levels. All patients were treated for brain edema with osmotic medications-either intravenous 20% mannitol or 10% hypertonic saline. In addition, some patients were treated with decompressive surgery.The patients will be followed up to 6 months and their modified Rankin Scale (mRS) will be recorded. A mRS score of 0-4 is considered as a favorable outcome while a score of 5-6 as an unfavorable one. Statistical differences in the different parameters between different groups at different time points will be analyzed by SPSS 22.0 software.

Inclusion Criteria:

• 1. 18-80 years old;
• 2. Clinical diagnosis of large hemispheric infarction
• 3. Within 48h after stroke onset.

Exclusion Criteria:

• 1. Clinical diagnosis of severe infection;
• 2. Clinical diagnosis of severe heart, liver or kidney diseases;
• 3. Clinical diagnosis of bleeding tendency, active bleeding or hematological diseases;
• 4. Malignant tumor;
• 5. Modified Rankin Scale (mRS)<2 before stroke onset.

Patients that are recruited into the Neuro-intensive care unit (NICU) of Xuanwu Hospital during 2018.1.1-2022.12.31