Smith R S, Lauria M R, Comstock C H, Treadwell M C, Kirk J S, Lee W, Bottoms S F
Department of Obstetrics and Gynecology, William Beaumont Hospital, Royal Oak, Michigan 48073, USA.
Ultrasound Obstet Gynecol. 1997 Jan;9(1):22-4. doi: 10.1046/j.1469-0705.1997.09010022.x.
The purpose of this study was to determine in what percentage of cases the assessment of placental localization using transabdominal sonography (TAS) was changed after transvaginal sonography (TVS) was applied. TVS was prospectively performed on all pregnant women of at least 15 weeks' gestation, when the placental edge using TAS appeared to be over or within 2 cm (low-lying) of the internal cervical os. The time required for the TVS scan and the distance of the placental edge from the internal cervical os were recorded. Of the 168 patients entered into the study, 131 were analyzed. Landmarks were poorly seen in 50% of the cases when using TAS. In 66 cases, the placenta appeared low or possibly over the internal cervical os using TAS, but a definitive diagnosis could not be made due to suboptimal visualization. In the remaining 65 cases, visualization of the internal os and placental edge was possible using both TAS and TVS. In this group, there was a change in the diagnosis in 26% of the cases after TVS was performed. Our results suggest that optimal visualization of the placental edge and internal cervical os is usually difficult with TAS when the placenta appears low-lying or over the internal cervical os. The assessment of placental localization was changed in over one-quarter of cases (26%) after transvaginal sonography was performed. The use of transvaginal ultrasound should be seriously considered when the placenta appears to be low or over the internal cervical os by transabdominal ultrasound.
本研究的目的是确定在经阴道超声检查（TVS）应用后，经腹超声检查（TAS）对胎盘定位的评估在多大比例的病例中发生了变化。对所有妊娠至少15周的孕妇进行前瞻性TVS检查，这些孕妇经TAS检查显示胎盘边缘位于宫颈内口上方或距离宫颈内口2 cm以内（低置胎盘）。记录TVS扫描所需时间以及胎盘边缘与宫颈内口的距离。在纳入研究的168例患者中，对131例进行了分析。使用TAS时，50%的病例中标志物显示不清。66例患者经TAS检查显示胎盘位置低或可能覆盖宫颈内口，但由于可视化效果不佳无法做出明确诊断。在其余65例患者中，TAS和TVS均能清晰显示宫颈内口和胎盘边缘。在这组患者中，TVS检查后26%的病例诊断发生了变化。我们的结果表明，当胎盘显示为低置或覆盖宫颈内口时，使用TAS通常很难清晰显示胎盘边缘和宫颈内口。经阴道超声检查后，超过四分之一（26%）的病例胎盘定位评估发生了变化。当经腹超声检查显示胎盘位置低或覆盖宫颈内口时，应认真考虑使用经阴道超声检查。
