Magnetic Resonance Tools for Fetal Developmental and Metabolic Assessment

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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.