Abstract： Objective To evaluate whether the number of high intensity transient signals(HITS)intraoperative detected by transcranial doppler ultrasound(TCD)can predict postoperative neuropsychological deficit.Methods Twenty patients scheduled for coronary artery bypass grafting(CABG)operation with cardiopulmonary bypass were enrolled in this study.HITS were recorded by TCD intraoperatively.And neuropsychological test battery was used to assess postoperative neuropsychological changes.Results There was no significant difference in the number of HITS compared with patients with or without neuropsychological changes.And multivariable correlation between the test scores and the number of HITS showed there was a weak correlation between RW Dgt-Dg5 and HITS(P＜0.05).Conclusion The number of HITS detected during cardiopulmonary bypass(CPB) do not!correlate with the postoperative neuropsychologial changes.