Non-invasive evaluation of human mucosal structures by multiphoton laser scanning tomography in vitro.

Background: Mucous membranes may be affected by various diseases and the diagnostic accessibility is limited. Multiphoton laser tomography (MPT) is a useful tool for in vivo evaluation of superficial skin structures and might also be useful for the imaging of mucosa.

Objectives: In order to investigate the suitability of MPT for the evaluation of mucous membranes, tissue samples of different donors and anatomical localizations have been imaged.

Methods: Human mucosa samples from the urinary bladder, palatine tonsil and ocular conjunctiva were investigated by MPT and subsequently compared with conventional histology.

Results: Horizontal images of the epithelium and the underlying connective tissue were obtained using the autofluorescence and second harmonics generation signals by MPT. The stratification of multilayered epithelium was consistently reproduced. Also inflammatory changes like lymphocytic infiltrates and widened intercellular spaces were imaged in some cases.

Conclusion: Mucous tissue samples were obtained and MPT imaging was successfully performed. In the direct comparison with histology of the same tissue samples, the characteristic morphology of the epithelia was found. Further studies are necessary in order to compare images of healthy and diseased mucosal epithelium and the use of MPT for its evaluation in vivo.