Currently available high-resolution endoscopy systems (high definition or HD) achieve a resolution of 1400x1080 pixels. Combined with conventional or virtual chromoendoscopy, preliminary clinical data indicate that the technical advancement of HD endoscopy is a decisive element of improved diagnostic investigation of early forms of cancer, and is able to exert an immediate impact on the prognosis of the disease for patients. In a large retrospective study Buchner was able to show, in 2430 patients, a significant rise in the detection rate of adenomas (HD 28.8% vs SR 24.3%, P = 0.012) by HD endoscopy1.
In another study Hoffman et al showed that high−definition endoscopes allow the recognition and characterization of subtle mucosal alterations in the distal esophagus and may help to differentiate patients with GERD from patients with functional diseases.
The study further suggests that a significant number of patients with so called NERD and with typical symptoms of reflux can be more precisely diagnosed by surface enhancement and Lugol chromoendoscopy. Patients with mucosal injury, and a considerable number of subtle mucosal lesions, can be detected at the gastroesophageal junction after i−scan by visualising formerly invisible alterations by their vessel or crypt architecture. In summary, the study concludes that high−definition endoscopy with surface enhancement (i−scan) is simple and useful for the diagnosis of lesions in the distal oesophagus. This method could be appealing for the endoscopist, because it is easy, safe, and can be performed during the same endoscopic session just by pressing a button2.
High-Definition (HD+) endoscopy combined with i-scan technology provides excellent image quality, with a detailed visualisation. This combination supports the detection of epithelial changes. Enhancement of tumour margins and vessel architecture may lead to easier demarcation of suspicious areas and helps in characterisation of mucosal abnormalities. This will guide to determine where to take biopsies, or which areas need to be treated. Endoscopic diagnosis can therefore be significantly improved.
Van der Heijden et al. show in a study that the use of i-scan image enhancement technology in combination with HD bronchoscopy significantly improves detection of vascular changes especially with i-scan 2 offering the combination of surface enhancement and tone enhancement rendering a sharp and naturally colored image of the bronchial tree. Vascular changes have been shown to be correlated to angiogenic squamous metaplasia and lung adenocarcinoma or squamous carcinoma as was reported in other studies. Therefore facilitation of detection of these subtle changes is of clinical importance. It is likely that improvement of the image quality and additional image enhancement technology may improve the overall diagnostic yield of bronchoscopy and improve staging depending on the specificity and percentage of false positive findings in future studies. Furthermore better imaging may reduce procedure time when these techniques become widely available in bronchoscopes designed for every day use.
To sum this exploratory study up, it shows that high definition bronchoscopy with image enhancement technique (i-scan) may result in better detection of subtle vascular abnormalities in the airways. Since these abnormalities may be related to preneoplastic lesions and tumors this is of clinical relevance. Further investigations using this technique relating imaging to histology are warranted.3
1Kodashima et al: Novel image-enhanced endoscopy with i-scan technology. World J Gastroenterol 2010 March 7; 16(9): 1043-1049
2Hoffman A. et al. High-definition endoscopy with i-scan and Lugol's solution for more precise detection of mucosal breaks in patients with reflux symptoms. Endoscopy. 2009 Feb;41(2):107-12.
3Erik HFM van der Heijden et al. High definition bronchoscopy: a randomized exploratory study of diagnostic value compared to standard white light bronchoscopy and autofluorescence bronchoscopy. Respiratory Research (2015)
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