endomicroscope

An endomicroscope is an imaging device that enables in vivo microscopic examination of tissue during endoscopy. It delivers light to tissue and captures the resulting signals to produce histology-like images at cellular resolution. Endomicroscopy can be built into the tip of an endoscope or provided as a miniature probe that advances through the endoscope channel. It often uses fluorescent contrast to enhance tissue morphology.

The most common modality is confocal laser endomicroscopy (CLE). CLE scans tissue with a focused laser and an optical pinhole to reject out-of-focus light, producing high-resolution en face images of a superficial tissue layer. Two main formats exist: integrated CLE (iCLE) at the instrument tip and probe-based CLE (pCLE) via a fiber-optic probe. Other approaches include endocytoscopy, autofluorescence endomicroscopy, and light-based techniques. Imaging depth is shallow, typically up to a few hundred micrometers, with lateral resolution around a micron and a small field of view.

Endomicroscopy is used primarily in gastroenterology to assess mucosal pathology during endoscopy, including dysplasia in Barrett's esophagus, characterization of colorectal lesions, and evaluation of inflammatory bowel disease. It can guide targeted biopsies and provide real-time “virtual” histology, potentially reducing the number of conventional biopsies. Applications extend to hepatobiliary, pancreatic, pulmonary, and other organ systems, often as an adjunct to standard imaging.

Limitations include the need for contrast agents such as fluorescein, operator training for image interpretation, and cost. Depth and field of view remain restricted, and results can be operator-dependent. Endomicroscopy is generally used to complement, not replace, conventional histology.