Assessment of Diabetic Kidney Disease Using Ultrasound Localization Microscopy: An in Vivo Feasibility Study in Rats

Diseases such as diabetes mellitus can lead to chronic kidney disease (CKD). The early diagnosis of CKD is of significant importance to prevent it from rapid deterioration, while the current methods used in the clinic is susceptible. As one of the major complications of diabetes, diabetic kidney disease (DKD) leads to the significant changes of renal microvasculature and perfusion in the early stage. However, they cannot be observed by conventional imaging methods. Ultrasound localization microscopy (ULM) has been developed in recent years to significantly improve the spatial resolution of ultrasound imaging by localizing the microbubbles (MBs) flowing in microvasculature. This technique can not only obtain the microvasculature in deep tissue, but also provide an accurate blood velocity map. In this study, ULM was performed on an acute ischemic-reperfused rat kidney model and a normal rat kidney to investigate its in vivo feasibility in evaluation of DKD. The microvascular morphology and velocity maps of the kidneys were obtained. Results show that under current experimental conditions, a resolution of 36 μ m is reached. Much less MB events (70 k vs 160 k from 6, 000 frames) and much lower mean blood flow speed (typically < 10 mm/s vs ~30 mm/s) were detected in the ischemic-reperfused kidney than in the normal kidney. This study shows the potential of ULM in the assessment of DKD/CKD.