Correlation analysis
The EA‐stimulation difference (EA_ POD 7 vs. POD 3) and group difference (HCs vs. patients at POD 3) were chosen as the regions of interest (ROI). The mean values in the ROI between the two groups were analyzed using the receiver operating characteristic curves. Pearson's correlation coefficients were calculated to indicate the relationship between the mean ALFF values in ROI in patients, where 