Glomerular structure and function play a key role in many diseases; however, accurate in vivo assessment remains a significant challenge due to limited spatio-temporal resolution of conventional imaging modalities and indirect clinical metrics such as glomerular filtration rate (GFR). In this study, we present high-frame-rate volumetric Ultrasound Localization Microscopy (ULM) with an expanded field of view as a noninvasive technique for imaging the entire rat kidney with micron-level resolution. Using a 1024-channel volumetric ultrasound system operating at 500 volumes per second, we acquired three consecutive volumes of the kidney, enabling visualization of glomerular-scale microvasculature and measurement of microbubble velocities within individual glomeruli. Validation of glomerular detection was performed by registering ULM and Light Sheet Microscopy (LSM) volumes of the same kidney, showing strong agreement in glomerular density estimates (ULM: 21.3 ± 8.0 /mm3 and LSM: 28.6 ± 7.5 /mm3). These results establish ULM as a reliable modality for noninvasive, high-resolutionimaging of glomeruli in vivo. In addition to structural detail, ULM provides access to hemodynamic information such as microvascular perfusion. This method lays the groundwork for future studies in renal physiology, with applications in early disease detection, monitoring of disease progression, and quantitative assessment of kidney function.
Gildemeister et al. (Wed,) studied this question.