Label-Free Dual-Modal Photoacoustic/Ultrasound Localization Imaging for Studying Acute Kidney Injury.

Growing evidence suggests a close link between acute kidney injury (AKI) and disruptions in renal microcirculation. However, current non-invasive tools for quantitatively monitoring structural and functional changes in renal microcirculation remain limited, making early diagnosis difficult. To address this challenge, this work introduces a label-free 3D multi-parametric imaging technique that combines photoacoustic and super-resolution ultrasound imaging. This approach provides high-resolution information on renal vasculature, hemodynamics, and oxygenation. This system offers the ability to visualize the entire renal vasculature at a resolution of 26 µm. In an AKI model, this work demonstrates a 54% reduction in vascular density, a 14.1% decrease in renal oxygenation, and a 61% decline in relative blood volume (rBV) 3 days post-surgery. The progression of kidney disease is further confirmed through blood tests and histopathological analysis of the collected kidney tissues. These findings indicate that this 3D renal imaging technique holds substantial potential to advance the understanding of renal physiology and offers a valuable tool for investigating renal injury.