Detection of Pulsatile Oscillations via Ultrasound Localization Microscopy

Ultrasound localization microscopy (ULM) provides angle independent velocity measurements in vascular networks with sub-wavelength resolution, offering a potential alternative to conventional ecodoppler velocity estimation currently used in clinical practice. However, this increased sensitivity also makes the measurements noisier and more difficult to interpret, due to error accumulation across multiple steps of the ULM pipeline. To enhance interpretability, we propose to use physics-informed flow modeling to constrain and clarify velocity estimates. While the steady Poiseuille flow model is widely adopted, such approximation may fail to capture the vascular dynamics. In this study, we show that ULM is sensitive enough to resolve pulsatile flow oscillations. We evaluate six fluid dynamics models on in vitro data and show that considering pulsatility and slip boundary conditions lead to a more robust representation of the flow dynamics beyond noise.