Near real-time in vivo confocal imaging of mouse mammary tumors

The goal of this study was to evaluate the ability of near real-time reflectance confocal microscopy to image tumor metastasis in vivo in an animal model. An epi-illumination confocal microscope was used to capture images of mouse mammary tumors in nude immunodeficient and Balb/C immunocompetent mice. In vivo confocal images of normal and neoplastic areas were obtained before and after the application of a 6% acetic acid solution, with a lateral resolution of 0.8 microns and an axial resolution of 2-3 microns. Average imaging depths ranged from 150 microns to greater than 300 microns. We were able to differentiate between normal and abnormal tissue areas within the mammary gland, including areas of adipose tissue, fibroblasts and connective tissue, and neoplastic tissue. In vivo imaging with reflectance confocal microscopy appears to be a useful tool to study tumor metastasis in vivo.