探索经腹部超声采集胎儿正中矢状切面的声窗及其应用价值。

通过12例引产胎儿前囟门、后囟门、矢状缝及前额缝分别获得颅脑正中矢状切面图，并将可行的声窗作为标准声窗对中孕期超声筛查的胎儿（头位组367例，非头位组384例）进行颅脑超声检查，并对两组胎儿获取正中矢状切面图的成功率进行比较。

中孕期超声筛查的751例胎儿成功获取颅脑正中矢状切面图497例。其中头位组获取颅脑正中矢状切面图的成功率为32.7%（32.7%，120/367），低于非头位组（98.2%，377/384），两组胎儿获取颅脑正中矢状切面图的成功率比较差异有统计学意义（P<0.01）。其中头位组采用前额、前囟门、矢状缝与后囟门4声窗联合检查采集颅脑正中矢状切面图的成功率为32.7%（32.7%，120/367），明显高于前额、前囟门、矢状缝与后囟门任何单一声窗采集图像的成功率（分别为17.2%、25.9%、1.6%、7.6%，P均<0.01）；非头位组4声窗联合检查采集颅脑正中矢状切面图像的成功率（98.2%，377/384）亦明显高于任何单一声窗采集的成功率（分别为31.8%、61.2%、64.8%、62.0%，P均<0.01）。

中孕期胎儿产前筛查经前额、前囟门、矢状缝、后囟门声窗均可获得颅脑正中矢状切面图，4声窗联合应用可增加颅脑正中矢状切面图的获得率。

This study intends to evaluate different acoustic windows that can be used to obtain the midsagittal plane of fetal brain during abdominal ultrasound scanning and the application of acoustic windows in practice.

The midsagittal planes were obtained respectively through anterior fontanel, posterior fontanel, sagittal suture and forehead seam of 12 aborted fetuses, and feasible acoustic windows were used as standard acoustic windows to obtain midsagittal planes of second trimester screening fetuses, which were divided into two groups according to the position of fetal brain, cephalic presentation group (367 cases) and non-cephalic presentation group (384 cases). The success rates were compared between groups.

Of the second trimester fetuses, 497 midsagittal planes of 751 cases were successfully obtained. The success rate of the cephalic presentation fetuses (32.7%, 120/367) was statistically lower than that of the non-cephalic presentation fetuses (98.2%, 377/384, P<0.01). Of the cephalic presentation fetuses, the combined acoustic windows acquisition success rate of the forehead, anterior fontanelle, sagittal suture and posterior fontanel acoustic window was 32.7% (32.7%, 120/367), significantly higher than the single acquisition success rate of the forehead, anterior fontanelle, sagittal suture and posterior fontanel acoustic window (17.2%, 25.9%, 1.6% and 7.6%, all P<0.01). Of the non-cephalic presentation fetuses, the combined acoustic windows acquisition success rate of the forehead, sagittal suture and posterior fontanel acoustic window was 98.2% (98.2%, 377/384), significantly higher than the single acquisition success rate of the forehead, anterior fontanelle, sagittal suture and posterior fontanel acoustic window (31.8%, 61.2%, 64.8% and 62.0%, all P<0.01).

The midsagittal plane of fetal brain can be obtained through forehead seam, anterior fontanel, posterior fontanel and sagittal suture acoustic windows in transabdominal screening. The combination of four acoustic windows can increase the success rate of obtaining midsagittal planes.