Validation of the spatial resolution of super-resolution ultrasound imaging using vessel mimicking microfluidic channels

Abstract

Super-resolution ultrasound (SRU) imaging is an emerging technology that can identify microvessels with unprecedented spatial resolution beyond the acoustic diffraction limit. Our group introduced a deconvolution-based SRU imaging technology and successfully applied it on mouse and human kidneys for assessing the renal microvascular changes during the progress of kidney diseases. However, a thorough validation on the most achievable spatial resolution has not yet been systematically performed due to the limitation with in vivo imaging including imperfect co-registration between SRU image and ground truth such as histology. In this study, we evaluated the spatial resolution of our SRU imaging algorithm using a custom-designed PDMS microfluidic channels as the ground truth. In the reconstructed SRU image, the two microchannels separated by wall-to-wall distance of 30 μm were successfully identified, which assured the expected spatial resolution of SRU using 15 MHz transducer. The validation using custom-designed microfluidic channels as the ground truth in the scale of tens of microns was performed for the first time to the best of our knowledge for SRU imaging. Such channels of various diameters and separation distances can be an effective tool for the systematic evaluation of the imaging capabilities of different SRU algorithms.