速度矢量成像技术评估儿童左心室扭转-位移环特点

Assessment of the changing characteristics of left ventricular twist-displacement loop in children with velocity vector imaging

目的应用速度矢量成像(VVI)技术观察正常儿童左心室扭转-位移环随年龄增长的变化特点。方法使用二维超声心动图采集73名3～14岁健康儿童左心室心尖和心底短轴切面图,以VVI软件脱机分析各切面的左心室扭转运动和短轴位移,比较不同年龄组(3～6、7～10、11～14岁)扭转-位移环的特点。结果左心室扭转-位移环呈8字形结构,收缩期的扭转和位移呈线性关系,其斜率随年龄增加而逐渐增大。在舒张早期,伴随解旋出现的径向扩张位移相对较小,导致各组的扭转-位移关系曲线较为陡直;在舒张中晚期,随着径向扩张位移的逐渐增大,扭转-位移环曲线趋向平坦。结论 VVI能有效、无创评价左心室扭转-位移环随年龄的改变;根据扭转-位移环评价儿童左心功能时,需考虑年龄因素的影响。

Objective To assess the changing characteristics of left ventricular （LV） twist-displacement loop of children with velocity vector imaging （VVI）. Methods Basal and apical LV short-axis images were acquired in 73 healthy children （aged 3 to 14 year-old） with 2-dimensional echocardiography. Then VVI software was used to analyze LV twist motion and radial displacement at each plane off-line. The characteristics of left ventricular twist-displacement loop were compared a- mong different aging groups （3--6, 7--10, 11--14 year-old）. Results The LV twist-displacement loop was like the con- figuration of ＂8＂. There was linear relation between twist and displacement during systole, and the slope increased gradual- ly with advancing age. During early diastole, the relatively small radial expand displacement appeared with untwisting, re- sulting in a much steeper twist-displacement relationship curve in each group, which became smooth gradually when the ra- dial expand displacement increased during mid to late diastole. Conclusion VVI can be used to effectively and noninvasively assess LV twist-displacement loop changing with aging. The impact of aging must be taken into account when evaluating LV function of children by the twist-displacement loop.