Multimodal Ultrasound and Photoacoustic Imaging of Placental Molecular Structure

Preeclampsia, affecting approximately 8% of pregnancies, is thought to initiate with inadequate vascular remodeling and development, with resulting changes in placental structure and molecular expression. While altered placental structure and molecular expression would be potentially valuable indicators of disease progression, they cannot be detected with existing ultrasound imaging systems. Our research develops ultrasound and photoacoustic imaging methods to characterize the progression of preeclampsia. In photoacoustic imaging, a nanosecond pulsed laser can be used to generate acoustic signals. By varying the wavelength of the laser, oxy- and deoxyhemoglobin concentrations within the tissue can be estimated as an indicator of tissue oxygenation. Using photoacoustic imaging, we have demonstrated in vivo changes in placental oxygenation and molecular expression in a rat model of preeclampsia. Additionally, molecularly targeted contrast enhanced ultrasound can be performed to assess molecular expression. Using molecularly targeted contrast enhanced ultrasound, we have demonstrate molecular expression changes in the presence of preeclampsia. These methods complementary knowledge and insight on the complex development of the placenta during preeclampsia.