![]() In an effort to decrease the high false-positive rates found with autofluorescence endoscopy when used as a standalone technique, the Amsterdam group subsequently combined autofluorescence endoscopy with narrow band imaging and optical zoom technology in a series of studies. In this study, 28 of 81 regions (35%) of abnormal fluorescence were associated with no dysplasia. When used as a standalone technique, however, autofluorescence endoscopy was still associated with a high number of false-positive areas of abnormal fluorescence. Kara and associates 165 found that video-based autofluorescence endoscopy increased the detection of high-grade dysplasia and early carcinoma lesions that were not seen with high-resolution white light video endoscopy. 164 Fiberoptic autofluorescence endoscopy was limited by poor image quality and poor maneuverability of the bulky imaging platform, making this technique of limited clinical value.Īlthough fiberoptic autofluorescence endoscopy seems to provide no advantage over conventional white light imaging, video-based technology, especially when combined with narrow band imaging, offers potential for enhancing endoscopic surveillance of Barrett's esophagus. ![]() Despite some promising preliminary studies, a randomized crossover trial of fiberoptic autofluorescence endoscopy versus white light video endoscopy in Barrett's esophagus found no difference in the detection rates for high-grade dysplasia or adenocarcinoma between the two techniques. 163Įarly work with autofluorescence endoscopy involved fiberoptic technology. It involves illumination of tissue of interest with short-wavelength light, which leads to excitation of endogenous substances known as fluorophores and emission of fluorescence light of longer wavelengths. Autofluorescence endoscopy is based on the principle that normal, metaplastic, and dysplastic tissues have different autofluorescence colors visible to the naked eye. Falk, in Clinical Gastrointestinal Endoscopy (Second Edition), 2012 Autofluorescence EndoscopyĪutofluorescence endoscopy is an imaging technique with the potential to examine a large surface area of GI mucosa rapidly to detect small areas of dysplasia or cancer. Because the autofluorescence signal is two orders of magnitude smaller than the fluorescence in fluorescein angiography, autofluorescence scanning needs to be performed before fluorescein is administered for angiography. However, focal hyper-autofluorescence is pathgnomonic for superficial optic disc drusen. Normally, the optic disc is not autofluorescent due to the absence of RPE cells in the optic disc area. Loss of autofluorescence is an indicator of RPE atrophy. It therefore serves as an indicator of RPE dysfunction and is seen in a large number of retinal disorders, for instance in Best's and Stargardt's disease. Therefore, it serves as a non-invasive indicator of the health of the RPE and outer retina: increased autofluorescence indicates abnormal accumulation of lipofuscin in the post-mitotic RPE cell. Retinal autofluorescence 2 relies primarily on the content of fluorophores in the lipofuscin granules of RPE cells. Göran D Hildebrand, in Pediatric Ophthalmology and Strabismus (Fourth Edition), 2013 Autofluorescence In a literature review, the median of GA progression monitored by FAF is ∼1.78 mm 2/year ( Fig. 5.2). 18 The following FAF photographs of six patients are excellent examples that quantitatively monitoring the progression of GA. Meanwhile, the blue light causes patient discomfort. However, FAF imaging is susceptible to media opacities, thus it is difficult to observe the fovea with macular pigment that absorbs blue light. 17 FAF imaging technique that employs a confocal scanning laser ophthalmoscope with a blue light excitation wavelength filter (488 nm) and an emission filter of 500–521 nm is currently the most commonly used method for FAF. As a result, FAF has been used as a morphologic marker for the progression of GA in clinical studies. Because of the demarcation between areas of RPE loss and neighboring areas of relatively intact photoreceptors and RPE, semiautomated quantification of atrophic areas by FAF is applicable. Atrophic areas represent decreased autofluorescence (hypoautofluorescence) due to the loss of the RPE cells. Weiye Li, in Age-Related Macular Degeneration, 2022 Fundus autofluorescenceįundus autofluorescence (FAF) is a specific modality for the evaluation of GA because it provides high-contrast retinal images detecting RPE atrophy.
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