Prenatal Diagnosis Of Congenital Anomalies

1. 四腔视摆技术（FAST）回声：一种新颖而简单的算法来可视化标准胎儿超声心动图平面：使用三维和四维超声的新算法已经产生，以简化胎儿超声心动图。利用一种新的三维超声显示技术（OmniView），我们开发了一种利用时空图像相关（STIC）体积数据集的算法，通过导管弓的纵向视图绘制四条解剖线。该算法在50例妊娠15.3 ~ 40周的正常胎儿心脏中进行了测试，计算了心脏诊断平面的显示率。该算法还在5例确诊的先天性心脏缺陷患者中进行了测试。在正常情况下，该算法能够在100%的情况下单独生成诊断平面（除了98%的三血管视图），98%的情况下同时生成诊断平面。在100%的正常病例中，摆动技术能够生成三血管和气管视图、五腔视图和/或主动脉长轴视图、四腔视图和胃视图。在先天性心脏缺陷的情况下，图像显示的观点偏离了正常心脏的检查预期。本研究表明FAST回声算法简化了对胎儿心脏的检查，从而减少了对操作员的依赖。

1. Four-chamber view and swing technique (FAST) echo: a novel and simple algorithm to visualize standard fetal echocardiographic planes: Novel algorithms using three- and four-dimensional ultrasound have been generated to simplify fetal echocardiography. Using a new display technology (OmniView) for three-dimensional ultrasound, we developed an algorithm using spatiotemporal image correlation (STIC) volume datasets by drawing four dissecting lines through the longitudinal view of the ductal arch. The algorithm was tested in 50 normal fetal hearts between 15.3 and 40 weeks of gestation, and the visualization rates of cardiac diagnostic planes were calculated. The algorithm was also tested in five cases with proven congenital heart defects. In normal cases, the algorithm was able to generate the diagnostic planes individually in 100% of cases (except for the three-vessel view, which was seen in 98%), and simultaneously in 98%. The swing technique was able to generate the three-vessels and trachea view, five-chamber view and/or long-axis view of the aorta, four-chamber view and stomach in 100% of normal cases. In cases of congenital heart defects, the images displayed views that deviated from what was expected from the examination of normal hearts. This study demonstrated that the FAST echo algorithm simplifies examination of the fetal heart, thereby reducing operator dependency. 2. Simple targeted arterial rendering (STAR) technique: a novel and simple method to visualize the fetal cardiac outflow tracts: A major challenge in fetal echocardiography is the visualization of the outflow tracts (aortic and pulmonary arteries). It is now clear that a fetal cardiac examination without adequate imaging of the outflow tracts is incomplete, and may miss major anomalies such as transposition of the great vessels. Imaging of the outflow tracts is operator-dependent and widely accepted to be non-satisfactory. We used OmniView to generate an algorithm which would reliably identify the fetal outflow tracts. Three dissecting lines were drawn through the four-chamber view of the heart contained in a STIC volume dataset. The technique was tested in 50 normal fetal hearts between 15.3 and 40.4 weeks of gestation and abnormal cases. The STAR technique was able to generate the necessary diagnostic planes in all normal cases. In fetuses with congenital heart defects, the STAR technique identified a ventricular septal defect and great vessel anomalies. The practical implication of this work is that physicians can now obtain fetal outflow tract views in most cases when a STIC volume is available. 3. Evaluation of fetal cardiac function with four-dimensional ultrasound using spatiotemporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL): Evaluation of the basic parameters of cardiac function in the human fetus is challenging and has relied on two-dimensional ultrasound examination, yet this approach relies on many assumptions about the anatomy of the fetal heart which have not yet been validated. Three- and four-dimensional ultrasound allow volumetric examination of the fetal heart, and therefore, determination of key parameters such as stroke output and cardiac volume. We conducted a cross-sectional study in normal pregnancies (19-42 weeks of gestation) to evaluate ventricular volume, stroke volume (SV), cardiac output (CO), and ejection fraction (EF). The CO was also expressed as a function of estimated fetal weight and biometric parameters. One hundred and eighty-four STIC datasets were analyzed. With advancing gestation, ventricular volume, SV, CO, and adjusted CO increased, while EF decreased. The RV volume was larger than the left ventricular (LV) volume in systole (0.50 vs. 0.27 mL) and diastole (1.20 vs. 1.03 mL). There were no differences between the LV and RV in SV, CO, or adjusted CO. LV EF was greater than the RV EF (72.2 vs. 62.4%). This study also provided reference ranges for the evaluation of fetal cardiac performance. 4. Collaborative study on 4-dimensional echocardiography for the diagnosis of fetal heart defects: the COFEHD study: Four-dimensional ultrasound (4DUS) with STIC is used to perform fetal echocardiography, and accumulating evidence indicates that this may facilitate examination of the fetal heart. We conducted a multi-center study to determine the accuracy of 4DUS in the diagnosis of congenital heart defects. Fetuses with and without confirmed heart defects were scanned between 18 and 26 weeks of gestation, and their volume data sets were uploaded onto a centralized file transfer protocol server. Ninety volume data sets were randomly selected for blinded analysis by international experts. Overall, the median (range) sensitivity, specificity, positive and negative predictive values, and false-positive and -negative rates for the identification of fetuses with congenital heart defects were: 93% (77%-100%), 96% (84%-100%), 96% (83%-100%), 93% (79%-100%), 4.8% (2.7%-25%), and 6.8% (5%-22%), respectively. There was excellent intercenter agreement ( = 0.97). This study demonstrates that 4D volume data sets can be remotely acquired and accurately interpreted by experts located at great distances from where patients were examined. These data suggest that tele-fetal echocardiography can be performed around the world.