Combined Speckle Variance Optical Coherence Tomography and Multiphoton Microscopy for in vivo Chick CAM Imaging

摘要

Combining optical coherence tomography (OCT) and multiphoton microscopy (MPM) can provide multimodal imagingof the microstructure of biological tissues. As a functional extension of conventional OCT, speckle variance OCT (SVOCT)can be applied to image microvasculature to improve the blood vessel visualization. In this paper, a combined SVOCTand MPM system is developed to visualize the chorioallantoic membrane (CAM) of a chick embryo, whichcontains extensive blood vessel network. Based on the different temporal decorrelation characteristics of the fluid flowand the surrounding stationary structure, SV-OCT enables enhanced contrast of fluid flow from the surroundingstructure. As a result, SV-OCT can achieve detailed mapping of the CAM microvasculature at the tissue level.Meanwhile, MPM enables vascular imaging at the cellular level, where two-photon excitation fluorescence (TPEF)images fluorescein dye injected into the blood stream, and second harmonic generation (SHG) visualizes the collagenfiber structures in the vessel wall and the surrounding tissues. Therefore, the combined SV-OCT and MPM systemprovides complementary information about the microvasculature structures in the chick CAM. The combined system isshown to be a powerful tool for interpreting the microvasculature, by allowing the visualization of the blood vesselnetwork in a relatively large field of view at the tissue level with SV-OCT, and by providing cellular-level information inlocal regions of interest with MPM.