Optical microangiography provides an ability to monitor responses of cerebral microcirculation to hypoxia and hyperoxia in mice.

In vivo imaging of microcirculation can improve our fundamental understanding of cerebral microhemodynamics under various physiological challenges, such as hypoxia and hyperoxia. However, existing techniques often involve the use of invasive procedures or exogenous contrast agents, which would inevitably perturb the intrinsic physiologic responses of microcirculation being investigated. We report ultrahigh sensitive optical microangiography (OMAG) for label-free monitoring of microcirculation responses challenged by oxygen inhalation. For the first time, we demonstrate that OMAG is capable of showing the impact of acute hypoxia and hyperoxia on microhemodynamic activities, including the passive and active modulation of microvascular density and flux regulation, within capillary and noncapillary vessels in rodents in vivo. The ability of OMAG to functionally image the intact microcirculation promises future applications for studying cerebral diseases.