MRI, Intra-vital, and Ex-vivo Fluorescence Microscopy of the Mouse Uterine Vasculature and Placenta

MRI and fluorescence microscopy provide complementary information on the structure and function of placental blood vessels. Due to the highly effective fetal-maternal barrier, dynamic contrast enhanced MRI using macromolecular contrast media probes exclusively the maternal blood flow in the placenta, providing information on the rate of flow into the placenta. Arterial spin labeling follows the motion of water across the fetal-maternal barrier, and thus this approach can provide information on perfusion. Arterial spin labeling achieved by tagging water passing through the uterine versus the ovarian arterial input, provide directional information for the two blood supplies, and can also help in non invasive positioning of the embryos along the uterine horns. Fluorescence intravital and ex vivo imaging provides for faster dynamic analysis and validation of maternal blood volume respectively.