McGahan J P, Phillips H E, Reid M H
Radiology. 1980 Feb;134(2):475-8. doi: 10.1148/radiology.134.2.7352234.
A total of 116 consecutive obstetric ultrasound examinations were reviewed. An anechoic area was observed at the placental-endometrial junctionin all 54 fundal placentas, 51 of the 52 posterior placentas, and 9 of the 36 anterior placentas. Detail was enhanced by use of a focused transducer with digital gray-scale equipment, and visualization of anterior placentas was improved by placing a water bath between the transducer and the skin surface. The anechoic area was seen beginning in the twelfth week of gestation and corresponds best to the dilated vessels of the decidua basalis.
共回顾了116例连续的产科超声检查。在所有54例宫底部胎盘、52例后壁胎盘中的51例以及36例前壁胎盘中的9例的胎盘-子宫内膜交界处观察到一个无回声区。使用带有数字灰阶设备的聚焦换能器可增强细节，并且通过在换能器和皮肤表面之间放置水浴来改善前壁胎盘的可视化。在妊娠第12周开始可见无回声区，其最符合基蜕膜的扩张血管。
