Development of Virtual Histology and Virtual Biopsy Using Laser-scanning Confocal Microscopy

The aim of this project is to acquire a direct image of histology from in vivo gastrointestinal mucosa. In other words, the task of `endo-microscope' is to observe the cellular architecture of tissue in vivo during routine endoscopic examination. As the first step to completing this study, resected fresh specimens from the oesophagus, stomach and colon were examined by laser-scanning confocal microscopy (LCM) (Fluoview, Olympus, Tokyo). Fresh untreated mucosal specimens obtained by endoscopic pinch biopsy, polypectomy or endoscopic mucosal resection were collected and placed in normal saline and examined by LCM, collecting the reflective light of a 488-nm wavelength argon laser beam. As the second step, a probe-type LCM `endo-microscope' was designed and applied to observe the human oral-cavity mucosa. The probe has 4.5-mm outer diameter and 20-cm length, which enables easy access to oral cavity mucosa. The estimated special resolution of the probe is 1-5 μm. A real-time microscopic image directly from ex vivo fresh specimens was acquired. The acquired LCM images corresponded well with the conventional H-E light microscopic images. Cell wall, nucleus and cytoplasm were simultaneously visualized by LCM scanning. This novel method enables serial imaginary microscopic sections on fresh specimens. In addition, a probe-type LCM `endo-microscope' was designed and was applied to observe human oral cavity mucosa. Virtual histological images from the living oral squamous cell were successfully obtained. LCM images from ex vivo fresh specimens demonstrated the features of the H-E staining histological image. In the next step to accomplish our project, we developed a LCM probe with 4.5-mm outer diameter to obtain a virtual image of human oral cavity mucosa.