血流向量成像定量评价正常婴幼儿心腔血流动力学

目的应用血流向量成像(VFM)技术定量观察正常婴幼儿心室腔内血流动力学变化。方法选取0.6～36.0个月的健康婴幼儿40名,中位月龄9.5个月。以VFM分别定量心尖四腔的左、右心室峰值血流速度在心腔内分布的位置,血流量峰值时间和每个心动周期正、反向累计血流量及心腔内涡流的数量、位置、出现时间和涡流量。结果左、右心室腔内舒张期峰值血流速度均位于心腔正中,而收缩期峰值血流速度均位于心腔内偏室间隔侧。心腔内的血流速度及血流量均自基底段向心尖段逐次递减,但同一心腔内各节段的血流量的达峰时间差异无统计学意义(P>0.05);心室内涡流多持续在等容收缩期;与右心室腔相比,左心室腔内涡流面积及涡流量均明显增高(P<0.05)。左心室腔内涡流量与体表面积、心肌质量呈正相关(P<0.05),与心率呈负相关(P<0.05)。结论 VFM技术能定量评价和可视化显示婴幼儿心腔内血流动力学的变化,可用于评价儿童心脏疾病。

Quantitive evaluation on hemodynamic changes of ventricular chambers with vector flow mapping in normal infants

Objective To quantitively observe the hemodynamic changes of the ventricular chambers in infants by vector flow mapping (VFM) based on Doppler echocardiography. Methods Apical four-chamber views in 40 healthy infants aged from 0.6 to 36 months (middle 9.4 months) were examined with VFM. Peak velocity and the position of blood flow in ventricular chambers, the time to peak flow volume, the blood flow for both directions in a single cardiac cycle and the number, position, appearing time and flow of the vortex were analyzed. Results The flow position of peak velocity was in the middle of the chamber in diastole, but leaning to the ventricular septum side in systole. Both the velocity and flow volume decreased gradually from basal to apical segment, but the time to peak flow remained similar of the three segments in same ventricle (P>0.05). The vortex mostly lasted during the isovolumic contraction interval. Compared with the right ventricular chamber, both the area and the flow of the vortex in left ventricular chamber were significantly larger (P<0.05). And the flow of the vortex in left ventricular chamber correlated positively with body surface area and myocardial mass (P<0.05), but negatively with heart rate (P<0.05). Conclusion VFM can be used to quantitively and visually observe the hemodynamic changes of ventricular chambers in infants, also may be used to evaluate the cardiac diseases in children.