Ultrahigh sensitive optical microangiography reveals depth-resolved microcirculation and its longitudinal response to prolonged ischemic event within skeletal muscles in mice.

The primary pathophysiology of peripheral arterial disease is associated with impaired perfusion to the muscle tissue in the lower extremities. The lack of effective pharmacologic treatments that stimulate vessel collateralization emphasizes the need for an imaging method that can be used to dynamically visualize depth-resolved microcirculation within muscle tissues. Optical microangiography (OMAG) is a recently developed label-free imaging method capable of producing three-dimensional images of dynamic blood perfusion within microcirculatory tissue beds at an imaging depth of up to ∼2 mm, with an unprecedented imaging sensitivity of blood flow at ∼4 μm∕s. In this paper, we demonstrate the utility of OMAG in imaging the detailed blood flow distributions, at a capillary-level resolution, within skeletal muscles of mice. By use of the mouse model of hind-limb ischemia, we show that OMAG can assess the time-dependent changes in muscle perfusion and perfusion restoration along tissue depth. These findings indicate that OMAG can represent a sensitive, consistent technique to effectively study pharmacologic therapies aimed at promoting the growth and development of collateral vessels.