中晚孕期正常胎儿大脑后动脉血流参数变化规律

目的：研究正常胎儿大脑后动脉(posterior cerebral artery，PCA)两个解剖节段的血流参数随孕周变化规律。方法：用多普勒检测132例正常单胎胎儿PCA两个解剖节段，PCA由基底动脉发出至后交通动脉之前节段(the firstsegment of posterior cerebral artery，PCAS1)和PCA与后交通动脉汇合之后节段(the second segment of posterior cerebralartery，PCAS2)的速度参数[收缩期峰值流速(peak systolic velocity，PSV)、舒张末期流速(end diastolic velocity，EDV)、时间-平均最大速度(time-average maximum velocity，TAMAXV)、速度时间积分(velocity time integral，VTI)]以及阻力参数[收缩期峰值流速与舒张末期流速比值(systolic peak velocity and end diastolic velocity ratio，S/D)、搏动指数(pulsatilityindex，PI)、阻力指数(resistance index，RI)]。将PCAS1和PCAS2血流参数分别与孕周行Pearson相关分析及多种曲线拟合，并对比分析两节段间的血流参数差异。结果：PCAS1和PCAS2速度参数随孕周增长而增加(P<0.0001)，速度参数与孕周均以Quadratic曲线拟合度最高(P<0.0001)。PCAS1和PCAS2阻力参数与孕周无明显相关性(P>0.05)。PCAS1阻力明显高于PCAS2(P<0.05)。结论：正常胎儿PCA两个节段速度参数均与孕周存在正相关关系，阻力参数与孕周不存在相关关系，两节段存在阻力差异。对正常胎儿PCA血流参数的研究可完善胎儿脑循环的评估，为高危妊娠的监测提供有力的根据及补充。

Blood flow parameters of posterior cerebral artery in normal pregnancy during middle and late stage

Objective: To study the blood flow parameters for 2 anatomical segments of posterior cerebralartery (PCA) in normal singleton fetal.Methods: Th e blood fl ow velocity parameters peak systolic velocity (PSV), end diastolic velocity(EDV), time-average maximum velocity (TAMAXV), velocity time integral (VTI) and resistanceparameters systolic peak velocity and end diastolic velocity ratio (S/D), pulsatility index (PI),resistance index (RI) for 2 anatomical segments in PCA were recorded. The first segment of thePCA (PCAS1) was recorded between the origin of PCA and the proximal part of the posteriorcommunicating artery. The second segment of the PCA (PCAS2) was recorded at the distal partof the posterior communicating artery. The blood parameters in both PCAS1 and PCAS2 wereanalyzed by using Pearson correlation and multiple curves fitting with gestational age (GA). Pairedstudent’s t test was performed to compare the difference in blood parameter between PCAS1 andPCAS2.Results: The blood flow velocity parameters in both PCAS1 and PCAS2 were increased withthe GA (P<0.0001), with the best fitted curves of Quadratic curve (P<0.0001). There were nocorrelations between resistance parameters in PCA and GA (P>0.05). Resistance parameters inPCAS1 were higher than those in PCAS2 (P<0.05).Conclusion: The blood flow velocity parameters in both PCAS1 and PCAS2 are increased withGA. The resistance parameters in both PCAS1 and PCAS2 do not change with GA. Study on thevelocities and resistance in these 3 arterial branches provides a more comprehensive evaluation onthe process of brain circulation.