Division of Fetal Imaging, Department of Obstetrics and Gynecology, William Beaumont Hospital, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan, USA.
Curr Opin Obstet Gynecol. 2011 Apr;23(2):117-22. doi: 10.1097/GCO.0b013e328342b730.
The incidence of placenta accreta is increasing as the number of cesarean sections increases. Separation of the placenta from the uterus in this situation may result in torrential bleeding. Antenatal diagnosis allows modification of the approach to delivery to conserve blood loss and avoid major medical problems.
Most of the imaging literature confines itself to patients who are at risk due to previous surgery and a placenta previa. In these patients, the most reliable sign of placenta accreta is the presence of irregular vascular spaces with arterial flow. In almost all patients, the signs needed for the diagnosis are present at the time of the screening examination at 18 weeks. Ultrasound is quite accurate in predicting severe placenta accreta in at-risk patients. Less severe cases, in which the placenta is solely difficult to separate, may not have any ultrasound findings. Nothing is known about the ultrasound appearance of placenta accreta in patients who have not had previous uterine surgery.
Antenatal identification of placenta accreta is possible with high sensitivity in patients with placenta previa and a previous cesarean section.
随着剖宫产数量的增加，胎盘植入的发病率也在增加。在这种情况下，胎盘与子宫的分离可能会导致大出血。产前诊断可以改变分娩方式，以减少失血并避免出现重大医疗问题。
大多数影像学文献仅限于因既往手术和前置胎盘而有风险的患者。在这些患者中，胎盘植入最可靠的征象是存在不规则的伴有动脉血流的血管间隙。在几乎所有患者中，在 18 周进行筛查检查时，就已经存在诊断所需的征象。超声在预测高危患者严重胎盘植入方面非常准确。在胎盘仅难以分离的不太严重的情况下，可能没有任何超声发现。对于没有既往子宫手术史的患者，胎盘植入的超声表现尚不清楚。
对于有前置胎盘和既往剖宫产史的患者，产前可以高度敏感地识别胎盘植入。
