Advanced Imaging Research Center, Oregon Health and Science University (OHSU), Portland, Oregon, United States of America.
Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center (ONPRC), OHSU, Portland, Oregon, United States of America.
PLoS One. 2022 Jul 19;17(7):e0270360. doi: 10.1371/journal.pone.0270360. eCollection 2022.
Existing methods for evaluating in vivo placental function fail to reliably detect pregnancies at-risk for adverse outcomes prior to maternal and/or fetal morbidity. Here we report the results of a prospective dual-site longitudinal clinical study of quantitative placental T2* as measured by blood oxygen-level dependent magnetic resonance imaging (BOLD-MRI). The objectives of this study were: 1) to quantify placental T2* at multiple time points across gestation, and its consistency across sites, and 2) to investigate the association between placental T2* and adverse outcomes. 797 successful imaging studies, at up to three time points between 11 and 38 weeks of gestation, were completed in 316 pregnancies. Outcomes were stratified into three groups: (UN) uncomplicated/normal pregnancy, (PA) primary adverse pregnancy, which included hypertensive disorders of pregnancy, birthweight <5th percentile, and/or stillbirth or fetal death, and (SA) secondary abnormal pregnancy, which included abnormal prenatal conditions not included in the PA group such as spontaneous preterm birth or fetal anomalies. Of the 316 pregnancies, 198 (62.6%) were UN, 70 (22.2%) PA, and 48 (15.2%) SA outcomes. We found that the evolution of placental T2* across gestation was well described by a sigmoid model, with T2* decreasing continuously from a high plateau level early in gestation, through an inflection point around 30 weeks, and finally approaching a second, lower plateau in late gestation. Model regression revealed significantly lower T2* in the PA group than in UN pregnancies starting at 15 weeks and continuing through 33 weeks. T2* percentiles were computed for individual scans relative to UN group regression, and z-scores and receiver operating characteristic (ROC) curves calculated for association of T2* with pregnancy outcome. Overall, differences between UN and PA groups were statistically significant across gestation, with large effect sizes in mid- and late- pregnancy. The area under the curve (AUC) for placental T2* percentile and PA pregnancy outcome was 0.71, with the strongest predictive power (AUC of 0.76) at the mid-gestation time period (20-30 weeks). Our data demonstrate that placental T2* measurements are strongly associated with pregnancy outcomes often attributed to placental insufficiency. Trial registration: ClinicalTrials.gov: NCT02749851.
现有的评估体内胎盘功能的方法无法在母体和/或胎儿出现疾病之前可靠地检测出有不良结局风险的妊娠。在此，我们报告了一项前瞻性双部位纵向临床研究的结果，该研究采用血氧水平依赖磁共振成像（BOLD-MRI）定量测量胎盘 T2*。该研究的目的是：1）在整个妊娠期间的多个时间点量化胎盘 T2*，并确定其在不同部位的一致性，2）研究胎盘 T2与不良结局之间的关系。在 11 至 38 周的妊娠期间，316 例妊娠中完成了多达 3 次的 797 次成功成像研究。结果分为三组：（UN）无并发症/正常妊娠，（PA）原发性不良妊娠，包括妊娠高血压疾病、出生体重<第 5 百分位和/或死产或胎儿死亡，以及（SA）继发性异常妊娠，包括不属于 PA 组的异常产前情况，如自发性早产或胎儿异常。在 316 例妊娠中，198 例（62.6%）为 UN，70 例（22.2%）为 PA，48 例（15.2%）为 SA。我们发现，胎盘 T2在妊娠期间的演变可以很好地用 S 型模型来描述，从妊娠早期的高平台水平开始，T2持续下降，在 30 周左右出现拐点，最后在妊娠晚期接近第二个较低的平台。模型回归显示，从 15 周开始，PA 组的 T2明显低于 UN 妊娠，并持续到 33 周。相对于 UN 组回归，计算了个体扫描的 T2百分位数，并计算了 T2与妊娠结局的关联的 Z 分数和接收者操作特征（ROC）曲线。总的来说，UN 和 PA 组之间的差异在整个妊娠期间均具有统计学意义，中晚期妊娠的效应大小较大。胎盘 T2百分位数和 PA 妊娠结局的曲线下面积（AUC）为 0.71，在中孕期（20-30 周）具有最强的预测能力（AUC 为 0.76）。我们的数据表明，胎盘 T2测量与常归因于胎盘功能不全的妊娠结局密切相关。试验注册：ClinicalTrials.gov：NCT02749851。
