Endoscopic techniques are commonly used for esophageal and gastrointestinal screening. In this process, atypical
regions are identified by gross visual and morphological changes. These regions are then biopsied for pathological
confirmation prior to determining treatment. In an effort to increase the sensitivity of endoscopic screening, many
groups have performed work in developing microscopic endoscopes capable of inspecting tissues on a cellular level.
These microscopic endoscopes are generally implemented as either a stand-alone fiber or through the working channel
of a traditional endoscope, and are oriented in a manner similar to traditional flexible endoscopes, imaging the region
directly ahead of the endoscope with a wide-angle lens. However, this may not be the optimum configuration for
microscopic inspection of luminal sidewalls. We present a novel optical configuration for an endoscope that can
simultaneously function as a traditional forward-viewing macroscopic endoscope and as a sidewall-viewing microscopic
endoscope. With the first prototype, we have realized a water-emersion microscopic that is capable of imaging tissues
on a single-cell level. In addition, microscopic side-port configuration enables efficient mapping of the luminal wall.
Utilizing simultaneous macroscopic and microscopic imaging, we are developing software for image registration and
analysis that will enable localization of microscopic features within a macroscopic frame of reference. Through a
combination of microscopic sidewall imaging and software for image analysis, we aim to provide the clinician with the
equivalent of an in vivo biopsy, increasing screening effectiveness and decreasing discomfort and costs related to
performing multiple biopsies of suspected regions.