Department of Obstetrics and Gynaecology, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium; Department of Development and Regeneration, KULeuven, Herestraat 49, 3000, Leuven, Belgium.
Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium; Department of Inmaging and Pathology, KULeuven, Herestraat 49, 3000, Leuven, Belgium.
Placenta. 2019 Aug;83:1-4. doi: 10.1016/j.placenta.2019.06.002. Epub 2019 Jun 7.
We aim to compare two different methods for the assessment of placental sharing in monochorionic diamniotic twins: X-ray-angiogram and digital photograph of the placenta.
We included the placentas of a prospective series of twins that were followed from the first trimester onward and resulted in a double live birth or double stillbirth between April 2016 and February 2019. Injection was performed after delivery and an X-ray angiogram was made, as well as a digital photograph. On both of these, the territory of each twin was measured two investigators (IC and LL). Placental sharing discordance was determined using the following formula: (larger territory - smaller territory)/larger territory. We calculated the intra-class correlation coefficients for intra-observer and inter-observer reliability and used Bland-Altman analysis to compare both methods.
77 placentas were included in the analysis. For both methods, there was an excellent intra- and inter-observer reliability. The mean difference in sharing (bias) on the X-ray and digital photograph using Bland-Altman analysis was 3,7% (95% CI 1,1% - 6,3%), where the digital photograph tends to overestimate the discordance. Limits of agreement were between -19% and 26%.
Delineation of the placental sharing on a digital photograph slightly overestimates the discordance. Since the venous territory on X-ray angiogram physically determines where each twin gets its oxygenated blood, X-ray angiogram may be a better method to determine placental sharing, although the digital photograph constitutes a valid alternative.
我们旨在比较两种评估单绒毛膜双羊膜双胞胎胎盘共享的不同方法：X 射线血管造影和胎盘数字照片。
我们纳入了 2016 年 4 月至 2019 年 2 月期间从孕早期开始随访的双胞胎的胎盘，最终结果为双活产或双死胎。分娩后进行注射，并进行 X 射线血管造影和数字照片检查。在这两种情况下，两位研究人员（IC 和 LL）测量每个双胞胎的胎盘区域。使用以下公式确定胎盘共享差异：（较大区域-较小区域）/较大区域。我们计算了观察者内和观察者间可靠性的组内相关系数，并使用 Bland-Altman 分析比较了两种方法。
77 个胎盘纳入分析。对于两种方法，观察者内和观察者间的可靠性均极好。 Bland-Altman 分析显示 X 射线和数字照片上的共享差异（偏差）的平均值为 3.7%（95%置信区间 1.1%至 6.3%），数字照片倾向于高估差异。一致性界限在-19%到 26%之间。
在数字照片上描绘胎盘共享会略微高估差异。由于 X 射线血管造影上的静脉区域实际决定了每个双胞胎获得含氧血液的位置，因此 X 射线血管造影可能是确定胎盘共享的更好方法，尽管数字照片构成了有效的替代方法。
