三维超声诊断胎儿小下颌畸形的价值

目的 应用三维超声定量检测胎儿下颌骨位置及大小,为产前诊断小下颌畸形提供理论依据。方法 采用经腹三维超声观察且比较188胎20~36孕周正常胎儿(正常组)及7胎小下颌畸形胎儿(异常组)下颌骨发育情况,测量胎儿颜面部角度及下颌骨宽度与上颌骨宽度之比,分析其与孕周的关系,并比较两组测量数据。结果 188胎中,成功测量178胎的全部下颌骨指标。正常胎儿颜面部角度为(62.37±6.23)°,与孕周无相关性(r=0.001,P=0.757),颜面部角度<49.90°诊断为颏后缩;下颌骨宽度与上颌骨宽度之比为0.98±0.09,在观察孕期内无显著变化,下颌骨宽度与上颌骨宽度之比<0.80诊断为下颌骨短小。7胎下颌骨短小且颏后缩,产前超声诊断为小下颌畸形,为产后或尸检结果证实。结论 应用三维超声测量胎儿颜面部角度及下颌骨与上颌骨宽度之比可在产前定量诊断小下颌畸形。

Value of three dimensional ultrasound in diagnosis of fetal micrognathia

Objective To quantitatively detect fetal mandible position and size with three dimensional ultrasound for diagnosis of fetal micrognathia. Methods The mandible was scanned with three dimensional ultrasound in 188 normal fetuses in 20-36 gestational weeks (normal group) and 7 fetuses with micrognathia (abnormal group). Fetal facial angle, width of the mandible and maxilla were measured. The ratio of the width of mandible and maxilla was calculated. The relationship between the above indexes and gestational weeks in normal fetuses was analyzed. The data of normal and abnormal group was compared. Results All the indexes of mandible were successfully measured in 178 of 188 fetus. There was no correlation of normal fetal facial angle with gestational weeks (r=0.001, P=0.757). The average fetal facial angle was (62.37±6.23)°, when this angle less than 49.90°, chin recession was diagnosed. The ratio of the width of mandible and maxilla in observed period did not remarkably change. The average ratio was 0.98±0.09, when the ratio less than 0.80, mandible short was diagnosed. The 7 fetuses with chin recession and mandible short were diagnosed as micrognathia, and then were confirmed by postnatal diagnosis or fetal autopsy. Conclusion Fetal micrognathia can be quantitatively diagnosed by three dimensional ultrasound using reconstructing of the mid-sagittal view and trasection of fetal facial, measuring fetal facial angle and calculate the radio of the width of mandible and maxilla.