Reflectance imaging by fiber bundle endoscope: Vertical reconstruction by multipositional illumination

Fiber bundles for imaging internal organs with minimum physical damage have been increasingly developed for both basic life sciences and clinical applications. Reflectance imaging is possible using fiber bundles for detecting the intrinsic optical contrast of blood vessels and tissue structure. The placement of an illumination source adjacent to imaging optics causes scattered light from deeper tissue layers to illuminate superficial tissues and results in a reflectance image. However, it does not have focal capacity and lacks depth resolution. In this study, we performed spatial analysis for the vertical reconstruction of in vivo tissues using a multipositional illumination scheme. The observed image corresponded to the “shadow” of a target object. When we manipulated the location of illumination, the shadow moved horizontally depending on the depth of the target. We used this horizontal displacement as a cue and successfully performed the vertical reconstruction of mouse brain blood vessels.