Abstract
Ultrasound particle image velocimetry (uPIV) has emerged as a widely-used tool for measuring blood flow fields with higher sensitivity and accuracy. However, its clinical application in assessing microvessel-related diseases is hindered by the diffraction limit. While ultrasound localization microscopy achieves super-resolution imaging of deep tissue microvessels, it lacks the capability for rapid imaging of blood flow dynamics. To overcome the challenges in measuring blood flows beyond the diffraction limit, we integrated the strengths of super-resolution ultrasound and uPIV strategies, proposing an approach termed enhanced ultrasound particle image velocimetry (E-uPIV). By the reconstruction of high-resolution microbubble trajectory images and subsequent speckle tracking, E-uPIV accurately maps microvascular structures and dynamically assesses microflow characteristics, eliminating the need of microbubble localization. This approach presents a perspective tool for non-invasively imaging dynamic microflows.