Fig 1: Correlation between relative difference of serum biomarkers and EIT extracted parameters for patients with normal and abnormal concentration of GFAP before surgery. (A) Heatmap of correlation coefficient between relative difference of GFAP protein and EIT extracted information. Significant correlations can be seen in group of CT1-GFAP < 327 pg/mL. (B) The correlation of TARIabs and relative difference of GFAP protein between T3 and T1 for patients with CT1-GFAP < 327 pg/mL. (C) The correlation of TARIabs and relative difference of GFAP protein between T4 and T1 for patients with CT1-GFAP < 327 pg/mL. T2–T1 relative difference between after and before surgery, T3–T1 relative difference between 12 h after and before surgery, T4–T1 relative difference between 24 h after and before surgery, T5–T1 relative difference between 48 h after and before surgery, HCA hypothermic circulatory arrest, ΔARVHCA the difference of average resistivity value before and after HCA phase, kHCA the slope of electrical impedance during HCA phase, MRAIabs maximum of the absolute value of resistivity asymmetric index, TARIabs absolute value of time integral of resistivity asymmetric index; TARVHP time integral of electrical impedance for half flow of perfusion; *means p < 0.05.