In vivo monitoring of microvessels in skin flaps: Introduction of a novel technique

Orthogonal polarization spectral (OPS) imaging was validated against intrav ital fluorescence microscopy (IFM) for microvascular measurements in skin f laps of hairless mice. Examinations were performed 1, 6, and 24 hours after elevation (n = 8) with both OPS imaging and IFM. A fluorescent dye was a p rerequisite for IFM measurements but not for OPS imaging. Our findings show that OPS imaging can visualize the skin flap microcirculation independent from the application of fluorescent tracers. From these images, quantitativ e analysis of functional capillary density (FCD) was feasible. As expected, FCD was significantly lower in the distal part of the flap compared with i ts base (171.8 +/- 34.7 versus 62.0 +/- 25.6, mean +/- SD; 1 hour data). Co mparison of OPS imaging and IFM revealed a significant correlation of FCD v alues (P < 0.001) at all time points. Given the success of this validation study on mouse skin flaps, clinical investigations will have to prove that OPS imaging can also successfully be used to monitor flaps in humans. (C) 2 001 Wiley-Liss, Inc.