Objective To study the influence of begining time of cranial hypothermia treatment on the prognosis of extensive cerebral infarction(ECI) so as to extablish the optimum time for such treatment.

• 目的 观察头部低温启始时间对大面积脑梗死 (L CI)患者预后的影响 ,探讨头部低温最佳启始时间窗。