Magnetic Resonance Imaging (MRI) is a powerful tool that can be used to view the anatomy and function of organs in the body non-invasively. MRI in pregnancy could help identify problems during gestation so that women can be appropriately monitored and treated before there is substantial harm to the fetus. In collaboration with colleagues in Medical Physics and Radiology at the UW-Madison, we have developed MRI protocols to image utero-placental blood flow in pregnant rhesus monkeys throughout gestation, developing the ability to quantitatively determine blood flow to the uterus and perfusion of the placenta, in which maternal blood washes over the fetal tissue surface for nutrient transport and gas exchange. 

Since disruption of the perfusion of the placenta by maternal blood is associated with adverse outcomes such as preeclampsia, miscarriage, preterm birth, and stillbirth, we hypothesized that MRI could be a predictive tool for identifying at-risk pregnancies. Ferumoxytol, a superparamagnetic iron oxide nanoparticle (SPION) that has been used as a contrast agent in MRI, is phagocytized by macrophages, which accumulate at sites of inflammation allowing us to visualize, in real time and non-invasively, sites of ongoing inflammation while simultaneously using dynamic contrast enhancement (DCE) to quantify perfusion of the placental intervillous space. This can be coupled with other imaging modalities that can assess uterine blood flow. We have used ferumoxytol DCE and MRI to evaluate pregnancies impactedby Zika virus and have found that in the first trimester, placental perfusion is altered in placentas that exhibit histopathology when obtained at cesarean section at term. 

We are now embarking on a new study in which we will introduce immune regulators and thrombotic agents to generate inflammation and placental/decidual infarcts to develop a fetal growth restriction model, and test MRI as an imaging modality to detect placental lesions that can lead to adverse pregnancy outcomes.