Semi-automatic morphological measurements of 2-D and 3-D microvascular images

The technique of serial optical sectioning by laser scanning confocal microscopy (LSCM), in conjunction with off-line digital image analysis, was used to quantize the morphological changes occurring during angiogenesis and revascularization of pancreatic islets transplanted at the renal subcapsular site in rats. The process consisted of in-vivo imaging of the microvasculature which was optically enhanced by the administration of a fluorescent probe into the circulating blood. Serial two-dimensional (2-D) optical sections were obtained through the vascular bed at varying z-intervals in order to perform a computer reconstruction of the complete three-dimensional (3-D) morphology. Image processing algorithms such as gray level thresholding, median filtering, skeletonization, region labeling and template matching were applied to compute the vessel density, lengths and diameters of the neovasculature, and the tortuosity index