二维超声技术对胎儿腭部显示切面的探讨

Study on scan plane of fetal palate using two-dimensional ultrasound

目的总结中孕期及晚孕期胎儿腭部超声声像图特征。方法选取孕21～36周产前二维超声和产后检查证实腭部声像正常的1885例胎儿（中孕组1023例，晚孕组862例）的超声图像进行分析。检查中采用经胎儿颌下、口裂、耳前连续区域显示腭冠状切面，经口裂显示腭纵切面，连续完整显示胎儿正常腭部并统计显示率。结果产前超声经胎儿颌下、口裂至耳前区域腭冠状切面扫查两组胎儿正常硬腭显示为横带状强回声，正常软腭显示为横带状低回声；中孕组、晚孕组胎儿腭部超声显示率分别为76％（777／1023）、53％（458／862）；经口裂腭纵切面扫查胎儿正常腭部显示为连续弧形带状回声：中孕组、晚孕组胎儿腭部超声显示率分别为49％（501／1023）、13％（113／862）。冠状切面与纵切面联合扫查中孕组胎儿腭部超声显示率为94％（961／1023），晚孕组胎儿腭部超声显示率为56％（483／862）。结论中孕期胎儿存在明显的下颌骨软骨间隙，经胎儿颌下、口裂、耳前区域腭冠状切面及经口裂腭纵切面扫查不受胎头屈曲位置影响，二维超声可较完整显示胎儿腭部声像，有助于检出单纯性继发腭裂。但由于成像过程依赖于操作者的技术和手法，尚不能作为常规筛查方法。

Objective To analyze the ultrasonographic features of fetal palate in the second and third trimester. Methods Two-dimensional ultrasound was performed in 1 885 fetuses during 21 to 36 gestational weeks of pregnancy, including 1023 cases in 2rid trimester and 862 cases in 3nd trimester. The normal fetal palate ultrasound images were confirmed by postnatal examination. In the ultrasound examination, fetal palate coronary plane was scanned through submandibular region, oral fissure and prootic region; longitudinal plane was scanned through oral fissure. The detection rate of completely and continuously displayed fetal palate was calculated. Results In prenatal ultrasonography, the normal fetal hard palate was shown as a bright band and the normal soft palate as a hypoechoic band in coronary section through fetal submandibular region, oral fissure and prootic region. The detection rate was 76%（777/1 023）in 2^nd trimester group and 53%（458/862） in 3^rd trimester group. The normal fetal palate was shown as continuous camber echogenic band in longitudinal plane through oral fissure. The detection rate was 49%（501/1 023） in Ta trimester group and 13%（113/862） in 3^rd trimester group. The detection rate was 94%（961/1 023） in 2^nd trimester group and 56%（483/862） in 3^rd trimester group by the combination of two scanning approaches. Conclusions There is usually an obvious gap between mandible gristles in 2^nd trimester fetus. Fetal palate is accessible regardless of fetal head position by coronary scanning through submandibular region, oral fissure and prootic region and longitudinal scanning through oral fissure. These planes could display fetal palate well, and might be useful in detecting isolated secondary cleft palate. But these scanning approaches and planes might not suitable for routine screening due to operator dependence.