经颅多普勒超声对大脑后动脉发育不良的血流动力学检测

目的 应用经颅多普勒超声（TCD）分析大脑后动脉（PCA）发育不良的血流动力学特点并探讨TCD对其的诊断价值.方法 选择经TCD和磁共振血管成像（MRA）筛查的52例大脑后动脉交通前段（PCA-P1）发育不良的患者,进行颈动脉压迫试验前、后血流动力学改变的观察,并与52例无血管变异的健康者（对照组）比较.结果 ①52例PCA-P1发育不良患者的不良侧PCA-P1的收缩期峰值流速为（55±8）cm/s,低于对照组的（60±6）cm/s,差异有统计学意义（P〈0.01）.分别压迫同侧颈总动脉（CCA）后,发育不良侧的PCA-P1收缩期峰值血流速度为（192±25）cm/s,高于对照组的（96±14）cm/s,差异有统计学意义（P〈0.01）.发育不良者的PCA-P1收缩期峰值血流速度于颈动脉压迫试验前、后的比值（Vp后/Vp前）为3.52±0.53,高于对照组的1.60±0.17,差异有统计学意义（P〈0.01）.②压迫同侧CCA后,发育不良侧PCA-P1舒张期末血流速度与压迫前的比值（Vd后/Vd前）为4.48±1.28,高于对照组1.6l±0.25（P〈0.01）.③发育不良侧PCA-P1血管搏动指数为1.00±0.22,高于对照组的0.78±0.09,差异有统计学意义（P〈0.01）.④52例患者中有28例血流频谱呈高阻力型改变,24例血流频谱正常.同侧CCA压迫前、后,高阻力型频谱组与压迫前比值（Vd后/Vd前）为5.3±1.1,高于血流频谱正常组的3.5±0.6,差异有统计学意义（P〈0.01）,但VP后/VP前与正常频谱组间差异无统计学意义（P〉0.05）.⑤TCD疑诊PCA-P1发育不良者39例,经MRA确诊32例,阳性符合率为82.1%;其中表现为高阻力型血流频谱患者17例,经MRA确诊PCA.P1发育不良的有16例,阳性符合率为94.1%.结论 根据CCA压迫试验前后的PCA-P1的血流动力学变化参数,结合血流频谱形态,TCD可初步诊断PCA-P1发育不良.

Hemodynamic detection of posterior cerebral artery dysplasia with transcranial Doppler ultrasonography

Objectives To analyze the hemodynamic characteristics of dysplastic posterior cerebral artery with transcranial Doppler ultrasonography （ TCD ） and to investigate the diagnostic value of TCD. Methods Fifty-two patients with posterior cerebral artery PI segment （PCA-P1） dysplasia screened by MRA and TCD were selected. The hemodynamic changes before and after the carotid compression test were observed, and compared with 52 healthy subjects without abnormal blood vessels （control group ）. Results ①The blood flow velocity of 52 patients with PCA-P1 dysplasia on the dysplasia was 55 ± 8 cm/s on the dysplastic side, which was significantly lower than that of 60 ± 6 cm/s in the control group （ P 〈 0. 01 ）. After compressing the ipsilateral common carotid arteries （CCAs） respectively, the velocity of PCA-P1 on the dysplastic sides was 192± 25 era/s, and it was significantly higher than 96 ± 14 cm/s in the control group （ P 〈 0.01 ）. The ratio of velocity in patients with dysplasia before and after the compression test （after Vp/before Vp） was 3.52 ± 0.53, and it was significantly higher than 1.60 ± 0.17 in the control group （ P 〈 0.01 ）. ②After compressing the ipsilateral CCAs respectively, the end-diastolic flow velocity and the ratio before compression （ after Vp/before Vp） was 4.48 ± 1.28, and it was significantly higher than 1.61± 0.25 in the control group （P 〈 0.01 ）. ③PCA-P1 pulsatility index （PI） on the dysplastic sides was 1.00 ± 0.22, and it was significantly higher than 0.78± 0.09 in the control group （ P 〈 0. 01 ）. There was significant difference （ P 〈 0.01 ）. ④Of the 52 patients, the flow spectrum of 28 patients showed high-resistance changes and the flow spectrum of 24 patients was normal. Before and after com- pressing the ipsilateral CCAs, the ratio of high-resistance spectrum group compared to that before compressing （ after Vd/before Vd） was 5.3 ± 1.1, and it was significantly higher than 3.5 ± 0. 6 in normal blood flow spectrum group. There was significant difference （ P 〈 0.01 ）. However, there was no significant difference between after VP/before VP and the normal blood flow spectrum group. ⑤Dysplasia in PCA-P1 was suspected in 39 cases by TCD, and 32 of them were confirmed with MRA. The positive coincidence rate was 82.1%, 17 of them showed high-resistance flow spectrum, and 16 had dysplasia in PCA-P1 confirmed by MRA. The positive coincidence rate was 94.1%. Conclusion TCD in combination with blood flow spectrum shape may initially diagnose the dysplasia in PCA-P1 according to the changes of hemodynamic parameters of PCA-P1 before and after the CCA compression test.