Widefield and high resolution imaging modalities used in preclinical and clinical evaluation for the detection of colorectal cancer and esophageal cancer are reviewed.

Recent clinical studies have evaluated the sensitivity and specificity of widefield imaging techniques. The effectiveness of narrow band imaging has varied between studies, while the increased sensitivity demonstrated by autofluorescence imaging has often been accompanied by high false positive rates. With the aid of a contrast agent, chromoendoscopy has proven to be more effective than white light imaging in identifying neoplastic changes.

High resolution techniques including probe based confocal laser endomicroscopy, high resolution microendoscopy, and optical coherence tomography provide images of cellular architecture for smaller fields of view and have proven useful for targeting biopsies and for the real time assessment of margins following endoscopic mucosal resection.

In many cases, widefield techniques and high resolution imaging can combine molecular and morphologic imaging to yield increased sensitivity and specificity.

Preclinical approaches to enhance image contrast using vital dyes and molecular specific targeted contrast agents are being developed for both widefield and high resolution techniques.