Objective To numerically evaluate the value of the largest Lyapunov exponent on diagnosing the various stenosis degrees of internal carotid arteries in white rabbits and in order to diagnose the angiostegnosis with transcranial Doppler ultrasound ( TCD). 目的探讨血流信号的最大Lyapunov指数在诊断白兔颈内动脉不同程度狭窄中的价值,以期达到利用经颅多普勒超声(TCD)量化诊断血管狭窄的目的。