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Improvement in the visibility of colorectal polyps by using blue laser imaging

Yoshida N, Hisabe T et al

Gastrointest Endosc. 2015 Apr 4.

Background: Fujifilm developed blue laser imaging (BLI) via a laser light source with a narrow-band light observation function. It has a brighter BLI bright mode for tumor detection.

Objective: To investigate whether the BLI bright mode can improve the visibility of colorectal polyps compared with white light (WL).

Design: We studied 100 colorectal polyps (protruding, 42; flat, 58; size, 2–20 mm) and recorded videos of the polyps by using the BLI bright mode and WL at Kyoto Prefectural University of Medicine and Fukuoka Chikushi University Hospital. The videos were evaluated by 4 expert endoscopists and 4 nonexperts. Each endoscopist evaluated the videos in a randomized order. Each polyp was assigned a visibility score from 4 (excellent visibility) to 1 (poor visibility).

Setting: Japanese academic units.

Main Outcome Measurements: The visibility scores in each mode and their relationship to the clinical characteristics
were analyzed.

Results: The mean visibility scores of the BLI bright mode were significantly higher than those of WL for both experts and nonexperts (experts, 3.10 +/- 0.95 vs 2.90 +/- 1.09; P = .00013; nonexperts, 3.04 +/- 0.94 vs 2.78 +/- 1.03; P < .0001). For all nonexperts, the visibility scores of the BLI bright mode were significantly higher than those of WL; however, these scores were significantly higher in only 2 experts. For experts, the mean visibility scores of the BLI bright mode was significantly higher than those of WL for flat polyps, neoplastic polyps, and polyps located on the left side of the colon and the rectum.

Limitations: Small sample size and review of videos.

Conclusions: Our study showed that polyps were more easily visible with the BLI bright mode compared with WL. (Clinical trial registration number: UMIN000013770.) (Gastrointest Endosc 2015;82:542-9.)

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Ability of a novel blue laser imaging system for the diagnosis of colorectal polyps.

Yoshida N, Yagi N et al

Dig Endosc. 2014 Mar;26(2):250-8.

Background: A new endoscope system with a laser light source, blue laser imaging (BLI), has been developed by Fujifilm that allows for narrow-band light observation. The aim of the present study was to evaluate the utility of BLI for the diagnosis of colorectal polyps.

Methods: We retrospectively analyzed 314 colorectal polyps that were examined with BLI observation at Kyoto Prefectural University of Medicine between September 2011 and January 2013. The surface and vascular patterns of polyps detected by published narrow-band imaging magnification: Hiroshima classification were used. Correlations were determined between the classifications and the histopathological diagnoses. Additionally, the ability of BLI without magnification to differentiate between neoplastic or non-neoplastic polyps was analyzed.

Result: A total of 41 hyperplastic polyps, 168 adenomas, 80 intramucosal cancer, 11 shallowly invaded submucosal cancer, and 14 deeply invaded submucosal cancer were analyzed.Hyperplastic polyp was observed in 100% of Type A lesions (39 lesions), adenoma was observed in 89.3% of Type B lesions (159 lesions), intramucosal cancer and shallowly invaded submucosal cancer was observed in 69.6% of Type C1 (92 lesions) and in 84.6% of Type C2 (13 lesions), and deeply invaded submucosal cancer was observed in 81.8% of Type C3 lesions (11 lesions). The overall diagnostic accuracy of BLI with magnification was 84.3%. Additionally, the diagnostic accuracy of BLI without magnification for differentiating between neoplastic and non-neoplastic polyps <10 mm in diameter was 95.2%, which was greater than that of white light (83.2%).

Conclusion: BLI was useful for the diagnosis of colorectal polyps.

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Present and future status of flexible spectral imaging color enhancement and blue laser imaging technology.

Osawa H, Yamamoto H.

Dig Endosc. 2014 Jan;26 Suppl 1:105-15.

Abstract: The usefulness of flexible spectral imaging color enhancement (FICE) has been reported for evaluating the esophagus, stomach, and small and large intestine. Higher contrast is shown between cancer and the surrounding mucosa in the esophagus and stomach and may facilitate the detection of gastric cancers missed by white light imaging alone. The surface patterns of gastric mucosa are clearly visualized in non-malignant areas but are irregular
and blurred in malignant areas, leading to clear demarcation. Capsule endoscopy with FICE detects angiodysplasia and erosions of the small intestine. The surface and vascular pattern with FICE is useful for the differential diagnosis of colorectal polyps. However, FICE remains somewhat poor at visualizing mucosal microvasculature on a tumor surface. Narrow-band imaging (NBI) is dark in observing whole gastric mucosa and poor at visualizing mucosal microstructure. Blue laser imaging (BLI) has the potential to resolve these limitations. Narrow-band laser light combined with white light shows irregular microvessels on both differentiated and undifferentiated gastric cancer similar to those using NBI. In addition, irregular surface patterns including minute white zones are clearly seen on the uneven surface of differentiated lesions, resulting in exclusion of undifferentiated lesions. Using both distant and close-up views, a high contrast between green intestinal metaplasia and brown gastric cancer may lead to early detection of gastric cancers and determination of a demarcation line. BLI produces high-contrast images in esophageal cancer with clear vision of intrapapillary capillary loops and also predicts the histopathological diagnosis and depth of invasion in colorectal neoplasms.

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Blue Laser Imaging provides excellent endoscopic images of upper gastrointestinal lesions

Osawa H, Yamamoto H et al

VideoJ Encyclopedia GI Endoscopy. 2014;1, 607–10

Background/aim: Image enhanced endoscopy including narrow band imaging, flexible spectral imaging color enhancement and i-scan is usefulf or detailed examination of upper gastro-intestinal lesions.We aimed to clarify the usefulness of blue laser imaging (BLI) method, a new endoscopic system, to image upper gastrointestinal lesions.

Procedure: We observed upper gastrointestinal lesions including early gastric cancer and early esophageal cancer using white light images and subsequently BLI bright images and BLI images.

Results: In gastric cancer, irregular microvessels on the tumor surface are clearly identified for both differentiated and undifferentiated lesions with high magnification, similar to those using narrow band imaging. In addition, irregular surface patterns are seen in differentiated lesions by enhanced white circles, which form white zones on the tumor surface. Finding these circles allow us to rule out undifferentiated lesions. Another advantage is to enhance gastric intestinal metaplasia as green-colored mucosa in both distant and close-up views, leading to higher color contrast with brown gastric cancers. This leads to early detection of gastric cancers and shows a demarcation line between the cancer and areas of metaplasia. In squamous cell carcinoma of the esophagus, BLI produces a higher color contrast between brown lesions within traepithelial papillary capillary loop sand the surrounding area without magnification. The extent of Barrett‘s esophagus is easily shown as a high color contrast with the brown gastric mucosa.

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The ability of a novel blue laser imaging system for the diagnosis of invasion depth of colorectal neoplasms.

Yoshida N, Hisabe T et al

J Gastroenterol. 2014 Jan;49(1):73-80.

Background: Fujifilm has developed a novel endoscope system with two kinds of lasers that enables us to allow narrow-band light observation with blue laser imaging (BLI). The aim of this study was to evaluate BLI magnification in comparison with narrow-band imaging (NBI) magnification for the diagnosis of colorectal neoplasms.

Methods: This was a multicenter open study. A total of 104 colorectal neoplasms were examined with BLI and NBI magnifications in Kyoto Prefectural University of Medicine and Fukuoka University Chikushi Hospital. Vascular and surface patterns of tumors under BLI magnification were compared with those under NBI magnification, using a published NBI classification. The main outcome was the correlation between the NBI classification diagnosed by BLI or NBI magnification and the histopathological analyses.

Results: Sixty-two cases of adenoma, 34 cases of intramucosal cancer and shallowly invaded submucosal cancer, and eight cases of deeply invaded submucosal cancer were diagnosed. The diagnostic accuracy of BLI magnification in the NBI classification was 74.0 % (77/104), similar to that of NBI magnification (77.8 %). The consistency rate between BLI and NBI magnification in the NBI classification was 74.0 %. Concerning image evaluation, the interobserver variability of two expert endoscopists (N.Y. and T.H.) in BLI magnification was K = 0.863. On the other hand, the intraobserver variability of the two endoscopists was K = 0.893 (N.Y.) and 0.851 (T.H.).

Conclusion: BLI magnification by laser source could predict histopathological diagnosis and invasion depth of colorectal neoplasms. The diagnostic effectiveness of this method was similar to that of NBI magnification.