Volumetric Ultrasound Localization Microscopy of the Whole Rat Brain Microvasculature

Technologies to visualize whole organs across scales in vivo are essential for our understanding of biology in health and disease. To date, only post-mortem techniques achieve cellular resolution across entire organs. Here, we demonstrate in vivo volumetric ultrasound localization microscopy (ULM). We detail a universal methodological pipeline including dedicated 3D ULM, motion correction and realignment algorithms, as well as post-processing quantification of cerebral blood diameter and flow. We illustrate the power of this approach, by revealing the whole rat brain vasculature at a 14-fold improved resolution of $12 ~\mu \text{m}$ , and cerebral blood flows ranging from 1 to 120 mm/s. The exposed methodology and results pave the way to the investigation of in vivo vascular and hemodynamic processes across the mammalian brain in health and disease.