Confocal laser endomicroscopy is a newly developed diagnostic tool enabling in vivo histology during ongoing endoscopy. Endomicroscopy is possible due to the integration of a miniaturized confocal microscope into the distal tip of a conventional endoscope. A blue laser light is emitted and analyzes mucosal surface architecture in the gut at high resolution. Handling of the endoscope is similar to a standard video endoscope. Endomicroscopic images are displayed on a second monitor. The endoscope is advanced throught the esophagus. The blue laser beam is readily visible on the mucosal surface. Now the pylorus and the inflamed antrum are visible.
5 ml of fluoresceine is injected as a contrast agent at a final concentration of 10%. Fluoresceine is mandatory for endomicroscopic imaging. It highlights in vivo architecture of the mucosal layer and focuses first on the vessel architecture. The fine capillary network in the antrum is readily visible due to the bright bands characterizing single capillaries. Dark spots within the capillaries represent red blood cells. Subsequently a second dye is applied topically onto the gastric surface. Acriflavine is sprayed with a spraying catheter onto the mucosa. Acriflavine highlights cell boundaries and nuclei. In addition, Helicobacter pylori bacteria are brightly stained due to an active uptake of Acriflavine. Groups as well as single germs can be readily visualized on the mucosal surface and in between gastric glands. Foveolae gastricae, epithelial cells and Helicobacter pylori can be differentiated. The typical shape and size of single Helicobacter pylori can be identified allowing endomicroscopic targeted biopsies.
The confocal microscope is localized at the left lower corner in the macroscopic view. During confocal imaging tissue can be sucked into the working channel to minimize moving artifacts. Finally, we are working to obtain corresponding specimens for final histology. Ex vivo histology revealed Helicobacter positive gastritis. The patient was subsequently treated with antibiotics.
Ralf Kiesslich, M.D., University of Mainz, Germany