经颅多普勒超声对颈动脉病变侧支血流的评价

目的经颅多普勒超声（transcranial Doppler，TCD）的血流动力学参数评价侧支代偿能力的敏感性和特异性。方法经数字减影血管造影（digital subtraction angiography, DSA）证实的单侧颈动脉完全闭塞患者41例，依据DSA侧支分级分为完全代偿组和不完全代偿组，计算患侧大脑中动脉（MCA）与健侧MCA峰值流速的比值（dVMCA／nVMCA，及患侧MCA与健侧MCA搏动指数的比值（dPIMCA/PIMCA），比较代偿是否完全时，峰值流速比值和搏动指数比值的不同，通过ROC曲线分析，确定TCD评估标准。并分析TCD血流指标与侧支类别、数量的关系。结果TCD与DSA比较，评价大脑中动脉供血区域代偿较完全，dVMCA／nVMCA〉0．65时，敏感性为76％，特异性为75％，dPIMCA/PIMCA〉0．60时．敏感性为90％，特异性为60％。dVMCA／nVMCA、dPIMCA/PIMCA与侧支开放的数目无关。结论TCD能够通过血液动力学参数评价侧支血流代偿的程度，能够反映半球的灌注情况，评价侧支血流的多少比评价开放侧支的数量更有意义。

Transcranial Doppler evaluation on collateral flow in patients with carotid artery occlusion

Objective To determine the accuracy of transcranial Doppler(TCD) ultrasound,a noninvasive and cost-effective method,for evaluation on collateral flow in patients with carotid artery occlusion.Methods 41 patients with unilateral carotid artery occlusion were included and divided into two groups depend on the collateral degrees defined by DSA.Calculated the ratio of systolic flow velocity and pulsatility index of MCA in affected side with unaffected side(dVMCA/nVMCA and dPIMCA/nPIMCA) and compared the ratios between the groups.The ROC analysis was used to define transcranial Doppler criteria for distinct collateral degree.The ratios were also compared between the groups of different type and number of collaterals and between the carotid occlusion and control group.Results Compared with DSA,the sensitivity was 76% and specificity was 75% for dVMCA / nVMCA>0.65.The sensitivity was 90% and specificity was 60% for dPIMCA/ nPIMCA >0.60 to predict complete collateral flow in MCA region.The ratios of dVMCA /nVMCA and dPIMCA /nPIMCA did not associated with the number of cpllaterals.Conclusion Hemodynamic parameters of TCD can reflect the perfusion status of carotid disease.The extent of collateral supply is more important for clinic evaluation than the number of collaterals.