PurposeThe placenta is a vital organ for the exchange of oxygen, nutrients, and waste products between fetus and mother. The placenta may suffer from several pathologies, which affect this fetal‐maternal exchange, thus the flow properties of the placenta are of interest in determining the course of pregnancy. In this work, we propose a new multiparametric model for placental tissue signal in MRI.MethodsWe describe a method that separates fetal and maternal flow characteristics of the placenta using a 3‐compartment model comprising fast and slowly circulating fluid pools, and a tissue pool is fitted to overlapping multiecho T2 relaxometry and diffusion MRI with low b‐values. We implemented the combined model and acquisition on a standard 1.5 Tesla clinical system with acquisition taking less than 20 minutes.ResultsWe apply this combined acquisition in 6 control singleton placentas. Mean myometrial T2 relaxation time was 123.63 (±6.71) ms. Mean T2 relaxation time of maternal blood was 202.17 (±92.98) ms. In the placenta, mean T2 relaxation time of the fetal blood component was 144.89 (±54.42) ms. Mean ratio of maternal to fetal blood volume was 1.16 (±0.6), and mean fetal blood saturation was 72.93 (±20.11)% across all 6 cases.ConclusionThe novel acquisition in this work allows the measurement of histologically relevant physical parameters, such as the relative proportions of vascular spaces. In the placenta, this may help us to better understand the physiological properties of the tissue in disease.

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Long-lasting conductance changes triggered either by brief (millisecond) electrical stimuli and/or entry of calcium ions have been observed in a variety of excitable tissues. The electrical consequences of these events depend on the ion conductance affected and on the ion concentration gradient across the membrane, while the long-lasting nature of the change sustains the cell at either sub- or supra-threshold levels for activation of regenerative action potentials. We report here that many cultured mouse spinal neurones exhibit a voltage-activated chloride conductance that lasts for seconds and is dependent on extracellular calcium, [Ca2+]0. This conductance may repolarize and stabilize the cell at a level subthreshold for generating action potentials, thus complementing the functional roles of Ca-dependent K+ conductances.