Abstract: To study whether the transcranial doppler(TCD) ultrasonography parameters relate to the intracranial pressure(ICP) and the cerebral perfusion pressure(CPP) in severe brain injury patients. Methods： In consecutive 7 days, the peak systolic velocity (Vs), end diastolic velocity (Vd),mean velocity (Vm), resistance index (Ri)and pulsatility index (Pi) of the middle cerebral artery were determined by TCD ultrasonography in 40 patients with severe brain injury. The ICP, CPP and MAP were also determined. Results： There were inverse linear relationships between ICP and Vs, Vd, Vm, linear relationship between ICP and Ri, and exponential relationship between ICP and Pi. There were linear relationships between CPP and Vs, Vd, Vm, inversely linear relationship between CPP and Ri and inverse exponential relationship between CPP and Pi. prominent (rICP=0.809,　rCPP=-0.828 P＜0.001). In the context of 20?mmHg≤ICP≤50 mmHg and 40?mmHg≤CPP≤70?mmHg, ICP and CPP with Pi was also straightly related, and the relativity was better(rICP=0.864,rCPP=-0.887 P＜0.001). Conclusion： It is helpful by using TCD parameters in evaluating ICP and CPP qualitively and quantatively. It is promising to monitor the ICP and CPP noninvasively by studying parameters of TCD.

Key words: Transcranial doppler(TCD) ultrasonography, Brain injury, Intracranial pressure, Cerebral perfusion pressure