Super-Resolution Passive Cavitation Mapping with Diagnostic Ultrasound Arrays: A Preliminary Study

Passive cavitation mapping (PCM) has been developed to localize and quantify acoustic cavitation during ultrasound exposure, showing broad application prospects in ultrasound treatments. The traditional PCM algorithm, time exposure acoustics (TEA), produces poor image resolution when using diagnostic ultrasound arrays due to the limited diffraction modes. Although several advanced reconstruction algorithms have been developed, the limitation of imaging resolution still cannot be broken fundamentally. This work proposes a super-resolution PCM method implemented with diagnostic ultrasound arrays inspired by the rapid development of ultrasound super-resolution imaging techniques. This method uses a Gaussian fit to TEA-reconstructed original images to localize single cavitation sources, and combines the localization results of all sources to generate a super-resolution image. The super-resolution PCM method is preliminary tested by simulations and in vitro experiments. The simulation results show that this method localize the sources with an error of 46.48 and 38.66 µm for the linear and concentric-circle tracks. The experimental results suggest that this method can spatially resolve multiple cavitation sources in a local small area, having the potential to provide a tiny-scale observation tool for the studies on acoustic cavitation and benefit cavitation-mediated ultrasound treatments.