经颅多普勒超声评价大脑中动脉远端狭窄的方法及准确性分析

The Method and Accuracy of Transcranial Doppler Sonography in the Diagnosis of Distal Middle Cerebral Artery Stenosis

目的探讨经颅多普勒超声(TCD)评价大脑中动脉远段(M2段)狭窄的方法及可行性,为临床评价M2段狭窄提供重要的评价指标。方法选择磁共振血管成像(MRA)证实单侧M2段狭窄>50%的患者159例(病例组),TCD检测大脑中动脉近段(M1段)及M2段平均血流速度(MFV),计算M2段与M1段的MFV比率(M2/M1)及M2的非对称指数(AI),并与162例无脑动脉畸形及狭窄者(对照组)进行比较。同时计算各指标评价M2狭窄的准确性。结果病例组M2/M1显著大于对照组。ROC曲线显示M2/M1曲线下面积(0.957)最大,以0.97为截点值诊断M2段狭窄的敏感性和特异性分别为84.35%和86.22%,阳性预测值和阴性预测值分别为74.65%和91.24%。结论作为TCD的新指标,M2/M1可准确评价M2狭窄,TCD在M2狭窄的诊断、治疗及随访中具有重要作用。

Objective To evaluate the method and accuracy of transcranial doppler sonography（TCD） in diagnosis of the distal middle cerebral artery stenosis.Methods A total of 159 patients who underwent TCD and magnetic resonance angiography（MRA） were selected.Base on MRA,M2 stenosis was defend as 50 % in one lateral,TCD index of the M2/M1 ratio was defined as the ratio between the mean flow velocity（MFV） obtained at M2 and M1.The sensitivity and specificity of the M2/M1 ratio were calculated from the receiver operation characteristic curve.The asymmetry index and MFV were also investigated.A total of 162 healthy individuals were also enrolled as normal control.Results M2/M1 ratio was significantly higher in the patients group.Sensitivity and specificity for M2 stenosis were most satisfying when the M2/M1 ratio of 0.97 was adopted as the cutoff value.Conclusion The M2/M1 ratio may be a highly specific parameter for assessing M2 stenosis with TCD.TCD is highly accuracy for evaluating M2 stenosis.