Imaging Angiogenesis and Placental Function

Preeclampsia, a hypertensive disorder, is estimated to affect 5% to 10% of pregnancies. An initiating factor in the development of the disease is placental hypoxia. Using photoacoustic imaging, we have successfully monitored longitudinal, in vivo placental oxygenation in normal pregnancy and the reduced uterine perfusion pressure (RUPP) model of preeclampsia. Our current aim is to investigate the effect two potential therapies for preeclampsia have on placental hypoxia and maternal/fetal outcome.

Visualization of Vasodilation

Vasoactivity is an important physiological indicator of cardiovascular health which is frequently measured using ex vivo vessels to determine functional mechanisms and evaluate pharmacological responses. Currently, there are no imaging methods available to assess vasoactivity in multiple vascular beds of living animals noninvasively. In this work, we have developed methods to use photoacoustic tomography to assess vasoactivity in vivo in systemic vasculature of living animals. A spherical-view photoacoustic tomography system was used to monitor acute vasodilation in the whole abdomen of a pregnant mouse in response to injection of G-1. After 3D image reconstruction, the diameter of the iliac artery and photoacoustic signal intensity of a placenta over time was measured. The artery and placenta had differential response to the vasodilator G-1. We validated the observed vasodilation of artery by monitoring the change in cross-sectional diameter of an individual artery using standard B-mode ultrasound imaging.

Quantitative ultrasound imaging to assess placental microstructure

Quantitative Ultrasound Imaging to Assess Placental Microstructure

Quantitative ultrasound (QUS) analyzes the raw radiofrequency (RF) information from ultrasound image acquisitions to estimate the size, concentration, and organization of ultrasound scatterers that make up the tissue microstructure. Our goal is to apply QUS to detect changes in placental microstructure in vivo using an established rat model of preeclampsia.

Novel Contrast agents for transabdominal PA Imaging

Contrast enhanced photoacoustic (PA) imaging has the potential for deep tissue imaging, but clinically approved exogenous agents, such as indocyanine green (ICG), have poor photostability, low photothermal efficiency and poor blood retention that limit their use in vivo. Additionally, commonly used PA contrast agents have optical extinction peaks in the first near infrared (NIR-I) window, where light attenuation by tissue is high. Plasmonic nanoparticles (NPs) have high tunable localized surface plasmon resonance (LSPR)-induced optical extinction, allowing imaging at NIR-II wavelengths where light penetration is maximized in biological tissues. However, conventional plasmonic NPs, such as gold nanorods (AuNRs) bioaccumulate at sizes needed for NIR-II LSPR. Semiconductor nanocrystals (NCs), such as copper sulfides (CuxS), exhibit NIR-II optical extinction without size modulation. However, compared to AuNRs, typical CuxS have reduced peak LSPR due to lower densities of free charge carriers. Hence, our group is interested in characterizing novel biocompatible and biodegradable NIR-II PA contrast agent capable of translating PA systems for transabdominal imaging.

Contrast-enhanced ultrasound imaging of uterine and placental vasculature in vivo during preeclampsia

Targeted Contrast Enhanced Ultrasound Imaging

Using the targeted contrast enhanced ultrasound imaging (CEUS) technique to help detect the preeclampsia disease in the pregnant rat. Inject the Vevo Target-Ready MicroMarkers (FUJIFILM, VisualSonics), conjugated with biotinylated arginine-glycine-aspartate (RGD) into the pregnant rat through the tail vein injection.

Spectral photoacousti imaging measuring placental oxygenation in two models of preeclamptic rats.

Unlocking Preeclampsia Solutions: Investigating G Protein-Coupled Estrogen Receptor Activation In Preeclampsia

Pelvic organ prolapse happens when the muscles and tissues supporting the pelvic organs (the uterus, bladder, or rectum) become weak or loose. This allows one or more of the pelvic organs to drop or press into or out of the vagina. Many women are embarrassed to talk to their doctor about their symptoms or think that their symptoms are normal. But pelvic organ prolapse is treatable.