Symmetry 对称性
Symmetry refers to the size of the ventricles. Generally, the diameters of the right and the left ventricles are approximately a 1:1 ratio. As noted in Figure 9, in the hypoplastic left side of the heart, the left ventricle was much smaller than the right ventricle. Alternatively, in Figure 11 showing tricuspid atresia, there is marked discrepancy in size, with the right ventricle being much smaller than the left ventricle. In this example of tricuspid atresia, there is an association with VSD, identi?ed with color ?ow (Fig. 11).
对称性是指的心室的大小。通常情况下，左右心室直径的比例约为1：1。就如我们在图9中所看到的一样，心脏左侧发育不全，左心室比右心室要小很多。同样，在图11中显示的是由于三尖瓣闭锁导致左右心室明显的比例失衡，右心室比左心室小很多。在这例三尖瓣闭锁中还存在室间隔缺损，彩色血流可以证实（图11）。
FIGURE 11. A-C, Tricuspid atresia with VSD. A, Corresponding line drawing of tricuspid with VSD. B, The color Doppler ultrasound again demonstrates small RV as compared with LV. The color Doppler demonstrates the VSD. C, This 4-chamber view of the heart demonstrates a small RV as compared with the larger LV. Also note the small VSD (arrow).
图11.A-C 三尖瓣闭锁合并室间隔缺损。A，示意图；B，彩色多普勒超声显示右心室比左心室小，同时也发现有VSD；C，四腔心切面显示右心室比左心室小，同时也存在小的VSD（箭头）。
In Figure 12, there is some discrepancy in the size of the lumen of the right ventricle as compared with the size of the lumen of the left ventricle. This is an example of cardiac rhabdomyoma with associated thickening of the left ventricular wall. Usually, the right ventricle moderator band is thickened as compared with structures within the left ventricle. However, in this example, there is asymmetry in the lumen of the left ventricle as compared with the lumen of the right ventricle because of the associated cardiac rhabdomyoma. This is often associated with tuberous sclerosis.
在图12中左右心室的内径存在一些比例失调，这是一例心脏横纹肌瘤的病例，左心室室壁增厚。通常情况下，右心室的调节束与左心室的结构相比比较的厚，然而在这个病例中，因为存在心脏横纹肌瘤从而导致左右心室内径比例失调，这种病变经常合并有结节性硬化。
FIGURE 12. Rhabdomyoma of the heart. Four-chamber view of the heart demonstrates a well-circumscribed mass arising from the interventricular septum and protruding into the LV (arrow) corresponding to cardiac rhabdomyoma in this fetus with tuberous sclerosis. Note the thickening of the LV wall (curved arrow).
图12 心脏横纹肌瘤。 四腔心切面显示肿块边界清晰，来源于室间隔并且向左心室内凸起（箭头），符合心脏横纹肌瘤，胎儿还存在结节性硬化症。我们还可以看到左心室室壁增厚（弯曲箭头）。
Septum 间隔
The evaluation of septal defects can be done best on the 4-chamber view of the heart. However, the interventricular septum may also be visualized on the LVOT. In Figure 13, there is a small VSD, which is much more dif?cult to appreciate on real-time images than with the use of color ?ow. This is an isolated VSD. Often, VSDs may be associated with more complex cardiac anomalies, as identi?ed in Figure 11 showing tricuspid atresia with associated VSD.
检查间隔缺损时最好是在四腔心切面，然而在左室流出道也可以显示室间隔。图13中我们可以看到一个较小的VSD，在实时状态下要比彩色血流模式下难以发现，这是一个单发的VSD。通常，室间隔缺损会合并有其他心脏异常，就像图11中所显示的三尖瓣闭锁合并VSD。
Use of the PASSSS mnemonic is helpful for the basic examination of the 4-chamber view of the heart and may be helpful for the detection of complex cardiac anomalies, as outlined earlier.
运用PASSSS记忆法在进行基本的四腔心检查时很有用处，并且对于复杂心脏畸形有很有帮助，如上所述。
FIGURE 13. A and B, Small VSD. A, Real-time image showing small VSD (curved arrow). B, This is better identi?ed using color Doppler (curved arrow).
图13. 小型室间隔缺损。 A，实时状态显示较小的VSD（弯曲箭头）；B，在彩色多普勒模式下能更好的显示（弯曲箭头）。
Out?ow Tract Views 流出道切面
Using a routine out?ow tract views, conotruncal anomalies may be detected. In Figure 14, TGA is identi?ed because the aorta and the PA are parallel. On routine fetal cardiac examination, the PA should be noted to cross the aorta, and if this is not observed, then this may be a clue for conotruncal abnormalities (Fig. 14). Furthermore, when using out?ow track views, it is imperative that the vessel originating from the right ventricle is noted to bifurcate to ensure that this is the PA. In Figure 15, the vessel originating from the left ventricle is noted to bifurcate. This is the PA originating from the left ventricle as associated with TGA. As this view resembles the open mouth of a baby bird?s beak, this has been called the baby bird?s beak view. It is critical to note both the crisscross relationship of the PA and the aorta and the PA bifurcation.
通过常规流出道切面有时就可以发现圆锥动脉干畸形，在图14中由于主动脉和肺动脉平行排列我们可以确定是TGA。常规胎儿心脏检查时我们应该注意到肺动脉与主动脉是交叉走行，如果看不到这种走行就可能提示是圆锥动脉干畸形（图14）。此外，在进行流出道切面检查时务必要观察从右心室起源的血管是不是存在分叉从而确定是否为肺动脉。在图15中，起源于左心室的血管存在分叉，说明肺动脉起源于左心室，符合TGA。由于这个切面看上去像是一个小鸟张开的嘴，
因此被称为小鸟嘴切面。在流出道切面上我们一定要注意肺动脉与主动脉的交叉关系以及肺动脉的分成情况。
In situations in which this relationship cannot be demonstrated because of technical factors, then 5 short-axis views of the heart should be obtained (Fig. 7). In the 5 short-axis views of the heart, the right ventricle is noted to originate from the right side of the heart, with the pulmonary crossing the aorta to the left side of the thorax. The PA is also noted to bifurcate in the 5 short-axis views. In the 3-vessel view, the PA is larger, and the aorta lies centrally between the PA and the SVC. 如果由于技术上的原因不能显示两者的关系的话，我们应该找到心脏的5个短轴切面（图7）。在这5个短轴切面上，我们应该注意到右心室位于心脏的右侧，肺动脉与主动脉交叉向胸腔的左侧走行，在这5个短轴切面上也应该注意到肺动脉的分叉。在三血管平面上，肺动脉比主动脉大，而主动脉则位于肺动脉和上腔静脉中间。
Another example of an abnormal outflow tract could include truncal arteriosus. There are different types of truncal arteriosus, but most commonly, the trunk overrides the interventricular septum with an associated VSD, as seen in Figure 16. Other complex cardiac abnormalities may be identified in outflow tract views including tetralogy of Fallot and similar overriding aorta with associated VSD and small pulmonary outflow tract (Fig. 17). 另一个流出道异常包括动脉干，它有多种类型，但最常见的是动脉干骑跨室间隔合并室间隔缺损（图16）。在流出道切面上还可以发现其他的复杂性心脏畸形，包括法四、类似的主动脉骑跨合并室间隔缺损和肺流出道缩窄（图17）。
FIGURE 14. A and B, Transposition of the great arteries. A, Diagram shows transposition of the great vessels, with the aorta originating from the RV and the PA originating from the LV. B, An out?ow view shows the parallel course of the aorta and the PA rather than the normal perpendicular course of these vessels. AO, aorta. Adapted from 14A courtesy of Dr Gregory DeVore.
图14 A和B，大动脉转位。A，大动脉转位的示意图，主动脉与RV相连，肺动脉与LV相连。B，流出道切面显示主动脉和肺动脉平行走行而不是正常的垂直走行。
FIGURE 15. Transposition of the great arteries. A, This scan shows the PA originating from the LV. B, The PA bifurcation is shown, and the left branch of PA makes a sharp angle with the main PA and DA, reminiscent of a baby bird?s head with an open beak. Normally, the aorta exiting the LV should be traced to the aortic arch. The SP is to the left of the image, and the left side of the fetus is toward the transducer. Adapted from McGahan et al.
图15 大动脉转位。A，图像显示肺动脉与LV相连；B，图像显示肺动脉分叉，