The placenta is a unique organ directly responsible for fetal development and growth through a transient, yet critical interface between the mother and the fetus. With the increasing scientific evidence that modifiable maternal factors such as obesity may impact placental function, there is an increasing demand for the development of methods that directly assess placental structure and physiology in vivo and in real time across pregnancies in obese women. Currently, no validated method exists to directly detect differences in placental structure and function across gestation in pregnant obese women. As obesity is an environmental risk factor for pregnancy that is in epidemic proportions, detection of altered placental structure and function in this population would have an immediate impact, allowing better stratification of risk and monitoring of response to treatment. Magnetic resonance imaging (MRI) is nonsignificant risk and modality of choice for treatment decisions in many brain and cardiovascular disorders, as it offers a range of structural and functional imaging contrasts. Yet it has not made a significant impact on the assessment of placental structure and function due inhomogeneous magnetic fields and the complex nonrigid motion of the placenta driven by maternal respiratory rate, fetal heart rate and fetal motion. To address these barriers, we propose innovations from hardware through image acquisition, to post processing to optimize magnetic field homogeneity and mitigate random, non-rigid body motion. We will build on a currently funded Bioengineering Research Partnership, Advanced Fetal Imaging, to utilize a 128 channel receive array that will are building specifically for the pregnan abdomen and leverage its use through various means of acquisition acceleration to freeze placental motion. We propose to develop, implement and validate a set of MRI acquisitions and post processing strategies that assess placental structure and function including improved methods for placental structural imaging to determine its volume, metabolic profile, apparent diffusion, vascular anatomy, baseline oxygenation, perfusion, oxygen consumption (Aim 1) as well as oxygen and glucose transport (Aim 2). Further transformative approaches in comprehensive mathematical modeling of magnetic field inhomogeneities and placental motion are proposed to further mitigate image quality (Aim 3). Throughout, we will apply and evaluate the potential for each innovation to detect placental dysfunction due to obesity across pregnancy and correlate with pregnancy outcome (Aim 4). Benchmarks as well as milestones and go/no-go decision points are provided.
Currently there are no established methods to directly assess placental structure and function in vivo, across gestation limiting our ability to detect placental dysfunction that leads to unfavorable fetal outcomes in obese pregnant women. We propose to develop and assess the ability of novel MRI protocols (providing measurements of placental volume, metabolic profile, apparent diffusion, vascular anatomy, baseline oxygenation, perfusion, oxygen and glucose consumption and transport) to detect placental dysfunction in obese women.
|Jiang, Weiping; Zhou, Iris Yuwen; Wen, Lingyi et al. (2016) A theoretical analysis of chemical exchange saturation transfer echo planar imaging (CEST-EPI) steady state solution and the CEST sensitivity efficiency-based optimization approach. Contrast Media Mol Imaging 11:415-423|