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Electronic imaging has shown no utility in enhancing adenoma detection in average risk patients.
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Patients with Lynch syndrome or serrated polyposis syndrome may benefit from electronic imaging.
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Electronic imaging seems to offer limited benefit for patients undergoing surveillance for longstanding inflammatory bowel disease.
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The addition of molecular imaging probes may be needed to fully realize the benefits of electronic imaging for polyp detection in the colon.
Electronic Imaging to Enhance Lesion Detection at Colonoscopy
Section snippets
Key points
History of colonic polyp detection
The ability to reliably detect subcentimeter polyps is a relatively new phenomenon that has come with the advent of increasingly sophisticated endoscopic equipment. Before the 1950s, barium radiographic studies and rigid sigmoidoscopy were used for investigation of the colon. Flexible endoscopic visualization of the mucosa of the gastrointestinal tract was made possible by the development of a coherent optical fiber bundle by Hopkins and Kapany.26 This led to the development of the first
Autofluorescence imaging
Autofluorescence imaging (AFI) is another modality of mucosal enhancement manufactured by Olympus (Tokyo, Japan). Autofluorescence is the natural emission of light from biological molecules, endogenous fluorophores, when light of a suitable wavelength is absorbed. When cellular components and tissue state changes during pathologic processes, this alters the amount and distribution of endogenous fluorophores; hence, the autofluorescence generated. In neoplastic epithelial cells, there is
Average-Risk Populations
In average-risk populations, the use of NBI has been compared with WLE for detection of colonic lesions in 5 meta-analyses (Table 1). Overall, the evidence that NBI is better than WLE for adenoma detection is not convincing. Similarly, polyp detection was not improved with NBI and only 1 meta-analysis found that NBI increased detection of flat adenomas (95% CI, 1.09–3.52, P = .02).38
Other virtual chromoendoscopy modalities have limited data. A randomized, tandem trial in patients undergoing
Molecular imaging enhanced electronic imaging: an emerging technology
Given the overall lack of evidence supporting the routine use of electronic imaging modalities in surveillance colonoscopy to enhance polyp detection, further technological advancements are needed. Molecular imaging has the potential to facilitate this step forward in our endoscopic diagnostic and perhaps even prognostic ability. This technique takes advantage of molecular changes that occur early in the pathogenesis of disease and allows these molecular changes to be detected at endoscopy to
Summary
The current generation of electronic imaging either via virtual chromoendoscopy or AFI has not delivered the hoped for benefits in terms of polyp and specifically adenoma detection. Their use is not supported in average-risk patients in recent guidelines, and is only recommended for certain specific indications (the Lynch syndrome and serrated polyposis syndrome surveillance).74 The reasons for this may include a darker image, insufficient contrast versus background mucosa, and loss of
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2015, Techniques in Gastrointestinal EndoscopyCitation Excerpt :The 3 major endoscope manufacturers have their own proprietary electronic chromoendoscopy platform, as described later. Narrow-band imaging (NBI) has the most data available [33]. NBI (Olympus Medical Systems, Tokyo, Japan), uses a filter that produces only 2 “narrow bands” of light (415 nm and 540 nm) that correspond to the peaks of light absorption for hemoglobin, thus highlighting the vasculature within the mucosa and creating a contrast between the rest of the mucosa and the vasculature [32].