VFM评价正常成人左室心腔血流流场运动状态的初步研究

目的:运用VFM( Vector Flow Mapping)成像探讨正常成人左心室腔内收缩期血流流场特征.方法:健康成人志愿者40例(男22例,女18例),二维超声取心尖三腔观左室腔彩色血流信息动态图像存贮并脱机分析,将取样线分别置于左室腔基底段、中尖段和心尖段,获取心动周期内经取样线部位左室腔血流时间速度积分(Time-Flow curve, TF)变化曲线,记录基底段、中间段及心尖段收缩早期速度时间积分(ES-TF)、收缩中期速度时间积分(MS-TF)、收缩晚期速度时间积分(LS-TF).观察收缩期血流流场特征,观察涡流出现时间,测量涡流直径(横径Dx,)及涡流的最大向量速度(Vmax).结果:正常人左室心腔血流流场呈规则变化,收缩早期二尖瓣前叶下方可见涡流显示,收缩中期及晚期涡流消失.收缩早、中、晚期,血流时间速度积分测值由心尖段经中间段至基底段逐渐递增,差异均有统计学意义(P<0.05).收缩早期涡流直径约为(25.74±7.32)mm, 涡流最大向量速度均背离探头,大小为(38.31±14.25)cm/s,朝向探头速度大小为(11.42±6.28) cm/s.结论:应用VFM技术可清晰显示左室心腔内血流流场状态,左室腔血流速度积分测值可直观反应心腔内血流动力学变化.

Initial exploration of evaluation of left ventricular blood flow structure and dynamics in normal subjects by vect flow maping

Objective:To investigate the blood flow structure and flow dynamics during the ventricular systole stage by Vector Flow Mapping(VFM). Method:There were 40 healthy volunteers (22 male, 18 female)enrolled in this study. The apical three-chamber view and Color Dopper image in left ventricular(LV) were reserved and analyzed off-line. Time-Flow curves (TF) were obtained in cardiac cycle through the sample line in the basal, central and apical areas of LV. TF of early systole(ES-TF), mid-systole(MS-TF) and late systole(LS-TF) were recorded in the basal, central and apical areas of LV. Characteristics of blood flow structure of LV were observed during systolic, emergence time of vortexes, transverse diameters of eddies and maximum vector speed of the eddies. Result:The characteristic of flow structure had regular change in each of the cardiac phases, including early, mid-and late systole. During the early systolic phase, the circular arrangement of the vector (the eddy) was demonstrated at the anterior leaflet of mitral valve. The valves of ES-TF, MS-TF and LS-TF from basal areas to apical areas were gradually increased (P<0.05).The eddy was about (25.74±7.32)mm in diameter, and about (38.31±14.25)cm/s and(11.42±6.28) cm/s in the speed toward and from the outflow.Conclusion:The flow structure and dynamics of LV can be evaluated noninvasively by VFM, especially to obtain the mapping of the flow vector and time flow curve during individual cardiac phases and also to visualize the cardiac function.