Image from Wikipedia
I have a special interest in emerging technologies that may ultimately compete with histopathology in diagnosing pathologic lesions from tissue samples. I have posted a number of notes about molecular imaging but never any about endo-microscopy. A recent article about this topic caught my attention (see: Endo-microscopy Technique Shows Promise for Early Colon CA Diagnosis) and below is an excerpt from it, with boldface emphasis mine. Shown on the right is an image of a flexible endoscope.
...we [previously} profiled an endo-microscopy system from Paris-based Mauna Kea Technologies...[T]his company's main product, the Cellvizio fibered confocal microscopy system, allows a "practitioner to insert one of the miniprobes (only 300 um to 2.8 mm in diameter) into a conventional endoscope and record microscopic level movies of the tissue as fast as 12 frames/sec." The latest news is that Stanford University scientists tested the system in a small study, to evaluate the detection of early stages of colon cancer, and they were quite pleased with the results....The [scientists] found a short protein that sticks to colon cells in the early stages of cancer. Before screening a person, they spray that short protein attached to a fluorescent beacon into the colon. The protein then gloms on to any cancerous cells and creates an easily visible fluorescent patch. They then used a miniaturized microscope called Cellvizio GI, developed by Paris-based Mauna Kea Technologies..., to peer inside the colon and look for those telltale spots. Not only did the researchers see fluorescent patches, they could make out the individual cancerous cells.....In the initial trial with 15 patients, the technique detected 82 percent of the polyps that were considered cancerous by a pathologist.
Endomicroscopy, alternatively referred to as in-vivo microscopy, is defined in the following way: a newly developed endoscopic modality, which allows in vivo microscopy of the mucosal layer in about 1000-times magnification with subcellular resolution during ongoing gastrointestinal endoscopy. As noted above, the technique can be supplemented by a ligand protein + fluorescent label to enhance the ability to detect malignant transformation of colonic polyps real-time during GI endoscopy.
It's interesting that researchers are now combining the techniques of endomicroscopy with a fluorescent-labeled ligand to identify malignant transformation of polyps. In essence, the technique is being transformed into a type of molecular imaging managed by a gastroenterologist rather than a radiologist. However, in this former case, there is a human observer of the gross lesion supplemented by microscopic observation using a built-in confocal microscope. From the patient's perspective, the advantages of in-vivo real-time microscopy is that the malignant lesion(s) can be immediately detected and resected.
As a pathologist, I would have a few questions about the sensitivity/specificity of this technique. How would it label cells that we consider "dysplastic' for instance? What would be its false negative rate, risking nonremoval of a cancerous polyp that has invaded by the time of a re-exam? Given the relative ease of resecting most polyps, I can't see much benefit except for saving the pathologist's bill, given that the endoscopist would now charge more using this technique, plus a polyp excision charge for ones deemed "malignant".
Or am I missing something?
Posted by: bev MD | April 02, 2008 at 03:22 AM