title: Major mouse placental compartments revealed by diffusion-weighted MRI, contrast-enhanced MRI, and fluorescence imaging.
abstract: Mammalian models, and mouse studies in particular, play a central role in our understanding of placental development. Magnetic resonance imaging (MRI) could be a valuable tool to further these studies, providing both structural and functional information. As fluid dynamics throughout the placenta are driven by a variety of flow and diffusion processes, diffusion-weighted MRI could enhance our understanding of the exchange properties of maternal and fetal blood pools--and thereby of placental function. These studies, however, have so far been hindered by the small sizes, the unavoidable motions, and the challenging air/water/fat heterogeneities, associated with mouse placental environments. The present study demonstrates that emerging methods based on the spatiotemporal encoding (SPEN) of the MRI information can robustly overcome these obstacles. Using SPEN MRI in combination with albumin-based contrast agents, we analyzed the diffusion behavior of developing placentas in a cohort of mice. These studies successfully discriminated the maternal from the fetal blood flows; the two orders of magnitude differences measured in these fluids' apparent diffusion coefficients suggest a nearly free diffusion behavior for the former and a strong flow-based component for the latter. An intermediate behavior was observed by these methods for a third compartment that, based on maternal albumin endocytosis, was associated with trophoblastic cells in the interphase labyrinth. Structural features associated with these dynamic measurements were consistent with independent intravital and ex vivo fluorescence microscopy studies and are discussed within the context of the anatomy of developing mouse placentas.
authors: Departments of Chemical Physics.
authors: Eddy
authors: E
authors: Solomon
authors: Biological Regulation, and.
authors: Reut
authors: R
authors: Avni
authors: Biological Regulation, and.
authors: Ron
authors: R
authors: Hadas
authors: Biological Regulation, andKoret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, 76100 Israel; and.
authors: Tal
authors: T
authors: Raz
authors: Biomedical Magnetic Resonance Laboratory, Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110.
authors: Joel Richard
authors: JR
authors: Garbow
authors: Chemical Research Support, Weizmann Institute of Science, Rehovot, 76100 Israel;
authors: Peter
authors: P
authors: Bendel
authors: Departments of Chemical Physics, lucio.frydman@weizmann.ac.il michal.neeman@weizmann.ac.il.
authors: Lucio
authors: L
authors: Frydman
authors: Biological Regulation, and lucio.frydman@weizmann.ac.il michal.neeman@weizmann.ac.il.
authors: Michal
authors: M
authors: Neeman
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000494:pharmacology*; D005260:Female; D008279:Magnetic Resonance Imaging; D051379:Mice; D061848:Optical Imaging; D021041:Placental Circulation / Q000502:physiology*; D011247:Pregnancy / Q000502:physiology*; D014327:Trophoblasts / Q000166:cytology*
chemical_list: D003287:Contrast Media
keywords: high-field placental MRI; multimodal imaging; placental ADC maps; robust diffusion MRI