Longitudinal characterization of local perfusion of the rat placenta using contrast-enhanced ultrasound imaging

The placenta provides a wide range of physiologic functions critical for development. Insufficient placental perfusion resulting from improper vascular remodeling is linked to many pregnancy-related diseases including intrauterine growth restriction and preeclampsia. Here, we use contrast-enhanced ultrasound (CEUS) to assess longitudinal, in vivo placental perfusion through a pixel-wise time-intensity curve (TIC) analysis. CEUS images were acquired of the placenta of pregnant Sprague Dawley rats on gestational days (GD) 14, 16, and 18 after a bolus injection of gas-filled microbubble contrast agents. Conventionally, perfusion can be quantified using a TIC of contrast enhancement in an averaged region of interest. However, the placenta has a complex structure and flow profile, which is insufficiently described using the conventional technique. In this work, we apply curve fitting in each pixel of the CEUS image series in order to quantify hemodynamic parameters in the placenta and surrou...