Assessment of placental perfusion and oxygenation using novel MRI approaches.

在妊娠早期，滋养层细胞迁移到螺旋动脉腔，导致5-10倍终末 动脉扩张，从而增加通过胎盘的血流。胎盘功能不全与 螺旋动脉的这种转换失败，并导致最常见的妊娠并发症 如胎儿生长受限（FGR）和先兆子痫（PE）。在管理和治疗 妊娠并发胎盘功能不全，早期和可靠的检测是至关重要的，因为随着时间的推移， 胎盘功能障碍变得明显，胎儿或母亲的病理变化是不可逆的。 已经提出了许多方法来识别子宫内胎盘功能不全。特别是， 已经提出了各种基于MRI的方法来测量胎盘功能。然而，所有先前的研究都部署了 标准的脑MRI成像方案，没有对胎盘进行显著优化，或者使用了 对胎盘异常不太敏感在过去的几年里，我们已经推进了专用MRI 使用速度选择性动脉自旋标记进行胎盘特异性灌注和氧合测量的技术 （VSASL）和定量易感性作图（QSM），并已在我们的研究中证明了有希望的结果。 初步数据。在本研究中，我们将首先优化3 T下的胎盘VSASL，以提高信噪比， 图像质量（目标1）。然后，我们将应用我们的方法，胎盘VSASL和QSM在怀孕诊断 与FGR或PE和健康妊娠，以确定胎盘灌注和氧合之间的差异 FGR/PE和对照（目的2）。最后，我们将通过比较在体胎盘组织的MRI成像来验证我们的方法。 针对胎盘病理和临床结果的措施（目标3）。该项目的成功完成将 确定胎盘功能不全与体内胎盘灌注/氧合改变之间的相关性 测量.最终，这将开发出胎盘健康和疾病的早期和可靠的生物标志物， 协助制定和评估旨在改善妊娠结果的新的干预方法。

Early in pregnancy migration of trophoblast cells to the lumen of the spiral arteries leads to 5-10 fold terminal dilation of the arteries, thereby increasing blood flow through the placenta. Placental insufficiency is associated with failure of this conversion of the spiral arteries, and results in the most common complications of pregnancy such as fetal growth restriction (FGR) and preeclampsia (PE). In the management and treatment of pregnancies complicated by placental insufficiency, early and reliable detection is critical, because by the time placental dysfunction becomes evident, the pathological changes to the fetus or mother are irreversible. Numerous approaches have been suggested for identifying placental insufficiency in utero. Particularly, there have been various MRI-based methods proposed to measure placental function. However, all of prior studies deployed standard imaging schemes of brain MRI without significant optimization for the placenta or used the methods that are not very sensitive to placental abnormalities. Over the past several years, we have advanced dedicated MRI techniques for placental-specific perfusion and oxygenation measures using velocity-selective arterial spin labeling (VSASL) and quantitative susceptibility mapping (QSM), and have demonstrated promising results in our preliminary data. In this study, we will first optimize placental VSASL at 3 T for improved signal-to-noise ratio and image quality (aim 1). We will then apply our approaches of placental VSASL and QSM in pregnancies diagnosed with FGR or PE and healthy pregnancies to determine differences in placental perfusion and oxygenation between FGR/PE and controls (aim 2). Lastly, we will validate our MR imaging methods by comparing in-vivo placental measures against placental pathology and clinical outcomes (aim 3). Successful completion of this project will determine the association between placental insufficiency and altered in-vivo placental perfusion/oxygenation measurements. Ultimately, this will develop early and reliable biomarkers of placental health and disease, and will assist in developing and assessing new interventional approaches aimed to improve pregnancy outcomes.