Department of Ultrasonography, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, P.R. China.
Prenat Diagn. 2010 Nov;30(11):1057-63. doi: 10.1002/pd.2611.
The velocity vector imaging (VVI) technique is useful to assess regional myocardial mechanics. The aim of this study was to evaluate the usefulness of this technology in assessing regional right ventricular longitudinal functions in the fetus and to establish a nomogram of the right ventricle (RV).
We studied 170 healthy fetuses that were divided into five groups based on gestational age. Dynamic digital images of four chambers were collected and analyzed off-line. The longitudinal VVI parameters were calculated in the right free wall and ventricular septum, respectively.
A total of 151 out of 170 fetuses (89%) were successfully analyzed using VVI, with good inter- and intra-observer agreements. Normal values for velocity, strain, and strain rate were established. The tissue velocity gradually decreased from basal to apical segment (P < 0.05), whereas strain and strain rate remained stable. The tissue velocity increased with gestational age (P < 0.05), whereas strain and strain rate were stable (P > 0.05).
Fetal myocardial velocity, strain, and strain rate measurements are easy to obtain and are reproducible. From mid-to-late gestation, the longitudinal tissue velocity of the RV increases with gestational age, whereas strain and strain rate remain stable. These results indicate that myocardial contractility is established in mid-gestation and remains constant throughout gestation.
速度向量成像（VVI）技术可用于评估局部心肌力学。本研究旨在评估该技术在评估胎儿右心室（RV）局部纵向功能中的作用，并建立 RV 的正常图表。
我们研究了 170 名健康胎儿，这些胎儿根据胎龄分为五组。采集并离线分析四腔动态数字图像。分别计算右游离壁和室间隔的纵向 VVI 参数。
使用 VVI 成功分析了 170 名胎儿中的 151 名（89%），具有良好的观察者内和观察者间一致性。建立了速度、应变和应变速率的正常值。组织速度从基底段逐渐降低到心尖段（P < 0.05），而应变和应变速率保持稳定。组织速度随胎龄增加而增加（P < 0.05），而应变和应变速率保持稳定（P > 0.05）。
胎儿心肌速度、应变和应变速率测量易于获得且具有可重复性。从中孕期到晚期，RV 的纵向组织速度随胎龄增加而增加，而应变和应变速率保持稳定。这些结果表明，心肌收缩力在中期妊娠时建立，并在整个妊娠期间保持不变。
