Fig. 2 Images of the microcirculation dorsal skinfold preparation of the awake hamster taken during fluorescence intravital microscopy (a and c) and OPS imaging (b and d). Scale bar represents 100 µm. In a and b, images were taken of the same microvascular network, demonstrating similar contrast in vessels imaged using fluorescence intravital microscopy and OPS imaging. In c and d, representative images are shown from the same animal, which were used for FCD measurements. The black arrows indicate two hair shafts that can be seen in both images showing it is the same capillary network. The white arrows indicate the same capillary in both images. Intravital fluorescence microscopy shows all capillaries filled with the fluorescent marker and OPS imaging shows those capillaries that are filled with red cells. Capillary flow cannot be seen in a static picture. However, during playback of the videotape, the moving RBCs in the capillaries can be seen clearly using OPS imaging or by following dark particles moving in the fluorescent network. e, Plot of functional capillary density measurements under baseline conditions (n = 60), and after a 4-h pressure ischemia with 0.5 h of reperfusion (n = 60) or 2 h of reperfusion (n = 60). Data are shown as mean ± s.d.