Enhanced endoscopy in inflammatory bowel disease.

Abstract

Spectroscopy and OCT are two new methods for imaging the gastrointestinal mucosa. They both rely on the interaction of light within a tissue and have been adapted for use with endoscopes. It is unlikely that any one type of imaging modality will be able to reliably diagnose the presence of microscopic dysplasia. However, combining different methods may prove to be extremely accurate for detecting dysplasia and may therefore obviate a need for taking tissue biopsies. For instance, LSS may be most helpful in detecting early dysplasia because it is sensitive to changes in nuclear size and crowding. As more cells become dysplastic, fluorescence may play a role in defining changes in content of collagen or markers of metabolism (i.e. NADH). Finally, reflectance spectroscopy becomes useful in detecting characteristic changes in the tissue architecture as dysplasia progresses to invasive cancer. Using all three types of spectroscopy at once ("tri-modal spectroscopy") has proven to be extremely accurate for classifying Barrett's mucosa as either dysplastic or nondysplastic [9]. Our current method for detecting microscopic dysplasia relies upon random biopsies and interpretation of histology by pathologists. Interobserver agreement among even experienced pathologists regarding the presence or absence and degree of dysplasia in histologic specimens is not consistent [50]. Spectroscopy and OCT may ultimately provide new methods for accurately diagnosing dysplasia in real-time, without the need for tissue processing, and without the interobserver variations of histologic interpretation.