正常胎儿心脏肺循环血流的超声心动图特征

目的 :应用彩色多普勒超声心动图检测正常胎儿心脏肺循环血流 ,观察肺动脉及分支血流形态特点并探讨其意义。方法 :入选妊娠 2 0～ 4 1周的正常胎儿 339例。并按孕周分组 ,<2 8周为 组 ;2 8～ 36周为 组 ;>36周为 组 ;应用多普勒超声心动图观察肺动脉主干及分支血流形态 ,测量参数包括 :血流最大流速 (Vmax)、血流速度积分 (VTI)、血流加速时间 (ACT)、减速时间 (DT)及射血时间 (ET)、并计算瓣口血流量。结果 :1.正常胎儿心脏主动脉及肺动脉内径随孕周增加而增大 ,各孕周肺动脉内径均明显大于主动脉内径 ;2 .肺动脉瓣口血流速度低于主动脉瓣口血流速度 ,但肺动脉流量大于主动脉流量 ,且肺动脉流量与主动脉流量比值不随孕周而改变 ,始终保持恒定 ;3.动脉导管血流呈连续单向双期双峰血流 ,其收缩期流速始终明显高于主动脉瓣口及肺动脉瓣口流速。收缩期血流速度及收缩期与舒张期血流速度比值随孕周增加而增大 ;4 .肺动脉分支血流呈单向双峰 ,流速明显低于肺动脉瓣口流速 ,其血流形态表现为高阻力低灌注的特点。此形态孕早期即可出现 ,且不随孕龄的增加而改变。结论 :正常胎儿肺动脉循环系统的固有特点在孕早期即出现 ,并不随孕龄改变。因此早期应用彩色多普勒超声心动图检查 ,对判定胎儿心脏发育情况具

Color Doppler Echocardiography Used to Evaluate Normal Human Fetal Cardiac and Pulmonary Circulations and Blood Flow Characteristics

Objective:Color Doppler echocardiography was used to measure normal human fetal cardiac and pulmonary flow to observe the characteristics of the pulmonary artery and its branch flow.Methods:Three hundred and thirty nine normal fetuses were selected from 20 to 41 weeks of gestation.All cases were divided into three groups according to gestational ages:group 1,gestational age <28 weeks;group 2,gestational age between 28 and 36 weeks;group 3,gestational age >36 weeks.Color Doppler echocardiography was used to observe the characteristics of flow shape of pulmonary artery and its trunk.Parameters were measured as following:maximum velocity (Vmax)?time velocity intergral(VTI),and volumetric blood flow?accelerating time (ACT)?decelerating time(DT) and ejection time(ET)were calculated.Results:(1)Diameters of aortic and pulmonary arteries in normal fetal hearts increased with advancing gestational age and pulmonary arterial diameters were significantly larger than those of aortic artery at every gestational stage.(2)Peak velocity of pulmonary artery was lower than that of aorta,but the volume of the former was larger than that of the latter and the ratios of aorta and pulmonary artery were stationary at every gestational stage.(3)The shape of ductus arteriosus blood flow was consecutive?one-dimensional,double phasic and double peak.Its systolic velocity and the ratio between systolic and diastolic velocity increased with advancing gestational stage.(4)Blood velocity waveforms of the pulmonary artery branches demonstrated single-phasic and double peaks,the peak velocity was significantly lower than that of pulmonary artery and the waveform was characterized with high resistance and low perfusion.The waveforms existed at the early stage of pregnancy and remained stationary.Conclusions:The characteristics of normal human fetal pulmonary artery circulatory system appeared during the early stage of pregnancy,and unchanged throughout the gestation.Color Doppler echocardiography should be used at the early period of pregnancy to investigate whether the fetal heart is normal or not.