中文摘要：

目的探讨早孕期胎儿先天性半月瓣缺如的产前超声诊断特征。方法对超声心动图检查并诊断为先天性半月瓣缺如的21例孕11～13＋6周病例进行回顾性分析，归纳总结早孕期先天性半月瓣缺如的产前超声诊断特征及临床结局。结果21例先天性半月瓣缺如胎儿中，单纯肺动脉瓣缺如9例（42．9％）;肺动脉瓣合并主动脉瓣缺如12例（57．1％）。本组诊断半月瓣缺如的最小孕周为11＋5周，平均孕周为（12．0±0．7）周，平均头臀长约（60．2±6．6）mm。母体平均体质指数为（22．1±3．6）kg／m2。20例胎儿颈后透明层组织厚度（NT）增厚，范围2．4～12．4mm，平均NT值为（6．8±2．7）mm。早孕期先天性半月瓣缺如产前二维超声特征有NT增厚、胎儿水肿、颈部水囊瘤，心脏增大，心胸比值增大，多伴有心内和（或）心外畸形；彩色多普勒特征为三血管气管切面检测到主动脉和（或）肺动脉出现红蓝交替的往返血流信号，称为“进出征”，频谱多普勒显示双期双向血流流速曲线。结论先天性半月瓣缺如在早孕期有特征性表现，“进出征”和双期双向血流流速曲线是早孕期先天性半月瓣缺如的主要超声特征。

英文摘要：

Objective To describe the sonographic features of congenital absent semilunar valve diagnosed by first trimester ultrasound. Methods This retrospective study assessed the feasibility of first trimester ultrasound in detecting congenital absent semilunar valve. All cases diagnosed by first trimester fetal echocardiograms were identified using established perinatal database. Demographic information, sonographic images, perinatal outcomes, and autopsy reports were reviewed. Sonographic features were described. Results Among 21 cases diagnosed with congenital absent semilunar valve, there were 9 cases with APV（42.9%）, 12 cases with AAV and AAV（57.1%）. The earliest gestational age diagnosed with absent semilunar valve was 11 ＋ 5 week, mean gestational age at diagnosis was （12.0 ± 0.7） weeks and mean crown-lump length was （60.2 ± 6.6）mm. The mean maternal BMI was （22.1 ± 3.6）kg/m2. Twenty fetuses had increased NT ranging from 2.4- 12.4 mm [mean （6.8 ± 2.7）mm2. 2D sonographic feature of congital absent semilunar valve at the first trimester include increased NT thickness, generalized edema, cervical cystic hygroma, enlarged heart, increased C/T ration, and frequently associated with other additional cardiac abnormality or extracardiac abnormality. Color Doppler flow imaging revealed that biphasic bidirectional flow in the aortic arch and/or pulmonary artery at the 3VT view （＂to-and-fro＂ sign） is important to diagnose congenital absent semilunar valve at the first trimester. Conclusions Congenital absent semilunar valve has characteristic ultrasound images at the first trimester screening. ＂To-and-fro＂ flow pattern and biphasic bidirectional flow in the great arteries are key sonographic features in fetus with absent semilunar valve.