Endoscopic Molecular Imaging: Status and Future Perspective

Abstract

During the last decade, researchers have made great progress in the development of new image processing technologies for gastrointestinal endoscopy. However, diagnosis using conventional endoscopy with white light optical imaging is essentially limited, and ultimately, we still rely on the histopathological diagnosis from biopsy specimens. Molecular imaging represents the most novel imaging methods in medicine, and the future of endoscopic diagnosis is likely to be impacted by a combination of biomarkers and technology. Endoscopic molecular imaging can be defined as the visualization of molecular characteristics with endoscopy. These innovations will allow us not only to locate a tumor or dysplastic lesion but also to visualize its molecular characteristics and the activity of specific molecules and biological processes that affect tumor behavior and/or its response to therapy. In the near future, these promising technologies will play a central role in endoluminal oncology.

Utility of liquid-based cytologic examination of distal esophageal brushings in the management of Barrett esophagus: a prospective study of 45 cases

“…It is possible that new molecular methods will offer yet another method for detecting precancerous changes, and for the foreseeable future, application of a molecular diagnostic technique will require ex vivo testing on a sample of cells. While imaging techniques can theoretically detect molecular defects in vivo without need for a biopsy, 16 in practice these techniques are still far from being able to be routinely applied. 11 The role of chromosomal abnormalities detected by fluorescence in-situ hybridization on cytologic material from BE brushings has been promising and currently requires an ex vivo assay.…”

A Clinical Wide-Field Fluorescence Endoscopic Device for Molecular Imaging Demonstrating Cathepsin Protease Activity in Colon Cancer

“…Most of these technologies rely on visually assessing surface structure to determine demarcation borders, and highlighting mucosal details such as capillary and pit patterns on the colon wall, providing little or no functional information. Some techniques look at basic tissue architecture through fluorescence, or characterizing crevices and concave areas with the use of chromogenic dyes, while other techniques focus on microanatomic changes between normal and dysplastic lesions [37, 40, 42]. …”

“…The importance of functional information to guide endoscopy has been noted by other investigators, and molecularly targeted fluorescent probes have been tested in both mouse models and humans [6, 9, 15, 41, 42, 45–47]. Fluorescence endoscopy can play an important role, because several tumor-targeting molecular probes like peptides, antibodies, activated probes, and nanoparticles can be conjugated with fluorescent dyes and localized using a fluorescence endoscope.…”

Molecular endoscopic imaging in cancer

“…However, it is well accepted that WLE can miss a significant number of lesions including early cancers . To overcome these limitations, chromoendoscopy is used to enhance mucosal surface and vascular pattern morphology . However, because of a variety of staining materials and possible concentrations, the process is time‐consuming, sometimes inconclusive and cost‐expensive.…”

“…In principle, different classes of molecular probes could be used for molecular imaging studies. Table shows some widely used exogenous targeting agents …”