Towards quantitative CEUS assessments of ex-vivo feto-placental (micro)vasculature: A feasibility study

Placental dysfunction contributed to many pregnancy complications, highlighting the need to clarify normal placental mechanisms and improve early detection. Contrast-enhanced ultrasound (CEUS) has demonstrated utility in visualizing the (micro)vasculature across other fields of medicine. However, its use in obstetrics for detailed visualization and characterization of the placental (micro)vasculature remains to be validated. This pilot study explores the feasibility of CEUS for ex-vivo visualization of the fetal placenta, aiming to improve the understanding of feto-placental vascularization. It evaluates CEUS as a viable imaging method and its potential for quantifying vascular patterns in pregnancy complications, using advanced techniques like semi-quantitative CEUS and ultrasound localization microscopy (ULM) for detailed vascular assessments. In this ex-vivo feasibility study, CEUS imaging of the fetal side of the placenta was performed by injecting an ultrasound contrast agent (UCA) in the umbilical vein. This allowed assessing the (micro)vascular perfusion using semi-quantitative CEUS, by analysis of the gray-level time evolution. In addition, ultrasound localization microscopy (ULM) was used to characterize the (micro)vascular architecture at high resolution. Our finding demonstrate the feasibility of advances CEUS imaging approaches for both quantitative analysis and localization microscopy, providing high-resolution visualization and comprehensive characterization of the fetal side of the placental vasculature. • CEUS successfully visualized feto-placental vasculature in ex-vivo term placentas. • Temporal parameters were extracted for semi-quantitative assessment. • Future applications of (semi-)quantitative CEUS and ULM within obstetric care lie toward distinguishing normal and complicated pregnancies by differences in the placenta vasculature and hemodynamics.