High-resolution MRI reveals uteroplacental flow dynamics in a 3D-printed human placental cotyledon model.

Doppler measurements of the uterine arteries are indirect measures of the uteroplacental blood flow. Given that the intervillous flow cannot be resolved by clinical imaging, theoretical models are used to study the flow dynamics in the intervillous space (IVS). We propose an experimental method to visualize the flow within the IVS of a single placental cotyledon postpartum. At first, a cotyledon is measured by micro-computed tomography imaging. The reconstructed volume is then used to create a near-realistic placenta model. Four variations of arterial inlets are designed to simulate both normal and abnormal flow patterns. A scaled version of the model is printed in three dimensions. Magnetic resonance imaging-based velocity measurements inside the printed model, which is perfused with a Newtonian fluid at two Reynolds numbers, revealed that the flow patterns are primarily influenced by the Reynolds number and the dilation of the arterial inlet. The spiralization of the arterial pathway had only a minimal impact.