Super-resolution ultrasound imaging of microvasculature: Initial experiences in preclinical and clinical applications

Ultrasound localization microscopy (ULM) enables imaging of the microvasculature at spatial resolutions surpassing the limits of conventional ultrasound, while maintaining comparable penetration depth. This super-resolution technique relies on the localization and tracking of individual microbubbles (MBs) administered into the bloodstream, providing detailed visualization of microvascular structures and functions. However, clinical implementation of ULM faces significant challenges, such as low signal-to-noise ratio (SNR), tissue motion artifacts, and prolonged acquisition times. In this presentation, we will discuss advancements aimed at achieving robust and reproducible clinical implementation of ULM through a series of technical innovations and optimizations. These include signal enhancement techniques to boost MB SNR, advanced algorithms for accurate MB localization and tracking at clinically relevant dosages, optimized data acquisition strategies tailored to clinical workflows, and the development of 3-D imaging capabilities. Through pilot preclinical and clinical studies, we demonstrate the feasibility and efficacy of ULM in various applications, including chronic kidney disease (CKD), kidney transplant, liver disease evaluation, and beyond, in both animal models and human subjects under clinical scanning conditions. These findings underscore the transformative potential of super-resolution ultrasound imaging as a diagnostic tool, paving the way for widespread clinical adoption.