Magnetic Resonance Tools for Fetal Developmental and Metabolic Assessment

磁共振的相同物理原理允许获取高分辨率、高对比度的软组织三维图像，也可以被利用来获取有关组织的功能信息，如代谢物浓度和运输。*其中一种方法是磁共振光谱分析(MRS)。当应用于羊水样本时，MRS已被证明揭示了有关胎儿器官发育标志的信息，主要是肺和肾脏。然而，获取房颤样本仍然需要一个侵入性的程序来提取房颤(通过羊膜穿刺术)，这无意中增加了感染和早产的风险。在拟议的研究中，我们将开发一种MRS方案，允许对羊水(AF)进行非侵入性体内询问，从而创建一种更安全的替代技术来评估胎儿肺和肾脏的成熟度，从而允许早期识别胎儿的发育迟缓。*另一种利用光谱评估的方法是化学交换饱和转移(CEST)磁共振成像，它依赖于低浓度代谢物到丰富的水分子的自然磁化转移。选择的代谢物和水之间的持续磁饱和和转移允许代谢物的放大，从而更容易通过光谱学检测到代谢物，并可用于跟踪其运输和代谢。将这项技术应用于葡萄糖，一种名为葡萄糖CEST的方法，已被证明可以提供有关成年人大脑代谢率的信息。在拟议的研究中，我们将开发葡萄糖CEST作为评估胎儿器官代谢率的非侵入性工具。*葡萄糖CEST和AF-MRS将共同补充经典的胎儿磁共振成像，为评估胎儿器官成熟度和代谢功能提供安全和创新的手段。我们将在健康人类妊娠的动物模型上验证它们的使用，并使用临床级MRI扫描仪，从而提供它们潜在转化为临床实用的第一个原理证据。这些技术将通过增加在产前发育期间探测各种物种的生理学的新技术来彻底改变医学成像领域。这些技术还将有助于及早发现产前发育和功能缺陷，从而为医学领域做出贡献。

The same physics principles of magnetic resonance, which allow acquiring high-resolution, high-contrast, 3-dimensional images of soft tissue, could also be harnessed to acquire functional information about the tissue, such as its metabolite concentrations and transport. ******One such approach is MR Spectroscopy (MRS). When applied to samples of amniotic fluid (AF), MRS has been shown to reveal information about markers of fetal organ development, primarily the lungs and kidneys. However, acquiring an AF sample still requires an invasive procedure to extract AF (via amniocentesis), which inadvertently increases the risk of an infection and preterm delivery. In the proposed research we will develop an MRS protocol that allows for non-invasive in-vivo interrogations of amniotic fluid (AF), thereby creating a safer alternative technique for assessing fetal lung and kidney maturity, allowing for early identification of developmental delays in the fetus. ******Another approach that utilizes spectral assessment is Chemical Exchange Saturation Transfer (CEST) MRI, which relies on natural transfer of magnetization from low-concentration metabolites to the abundant water molecules. Continuous magnetic saturation and transfer between a chosen metabolite and water allows for amplification of the metabolite such that it is more easily detected through spectroscopy and can be used to trace its transport and metabolism. Applying this technique to glucose, a method termed glucoCEST, has been shown to provide information about brain metabolic rate in adults. In the proposed research we will develop glucoCEST as a non-invasive tool for evaluating fetal organ metabolic rate. ******Together, glucoCEST and AF-MRS will supplement classical fetal MR imaging, providing safe and innovative means of assessing fetal organ maturity and metabolic function. We will validate their use on animal models of healthy human gestation and using a clinical-grade MRI scanner, thereby providing the first proof of principle of their potential translation to clinical utility. These techniques will revolutionize the medical imaging field through the addition of novel techniques for probing physiology in a variety of species during prenatal development. These techniques will also contribute to the medical field by facilitating early detection of developmental and functional deficits prenatally.