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Blue laser imaging endoscopy system for the early detection and characterization of colorectal lesions: a guide for the endoscopist.

Togashi K, Nemoto D etc

Therap Adv Gastroenterol. 2016 Jan;9(1): Impact factor 3.883

Abstract: Blue laser imaging is a new system for image-enhanced endoscopy using laser light. Blue laser imaging utilizes two monochromatic lasers (410 and 450 nm) instead of xenon light. A 410 nm laser visualizes vascular microarchitecture, similar to narrow band imaging, and a 450 nm laser provides white light by excitation. According to three recently published reports, the diagnostic ability of polyp characterization using blue laser imaging compares favorably with narrow band imaging. No published data are available to date regarding polyp detection with blue laser imaging. However, blue laser imaging has the possibility to increase the detection of colorectal polyps by depicting brighter and clearer endoscopic images, even at a distant view, compared with first-generation image-enhanced endoscopy. A clinical trial to compare the detection between blue laser imaging and xenon light is warranted.


A computer system to be used with laser-based endoscopy for quantitative diagnosis of early gastric cancer.

Miyaki R, Yoshida S, etc

J Clin Gastroenterol. 2015 Feb;49(2): Impact factor 3.186

Goals: To evaluate the usefulness of a newly devised computer system for use with laser-based endoscopy in differentiating between early gastric cancer, reddened lesions, and surrounding tissue.

Background: Narrow-band imaging based on laser light illumination has come into recent use. We devised a support vector machine (SVM)-based analysis system to be used with the newly devised endoscopy system to quantitatively identify gastric cancer on images obtained by magnifying endoscopy with blue-laser imaging (BLI). We evaluated the usefulness of the computer system in combination with the new endoscopy system.

Results: The average SVM output value was 0.846 ± 0.220 for cancerous lesions, 0.381 ± 0.349 for reddened lesions, and 0.219 ± 0.277 for surrounding tissue, with the SVM output value for cancerous lesions being significantly greater than that for reddened lesions or surrounding tissue. The average SVM output value for differentiated-type cancer was 0.840 ± 0.207 and for undifferentiated-type cancer was 0.865 ± 0.259.

Conclusions: Although further development is needed, we conclude that our computer-based analysis system used with BLI will identify gastric cancers quantitatively.


Linked color imaging technology facilitates early detection of flat gastric cancers.

Fukuda H, Miura Y et al

Clinical Journal of Gastroenterology. 2015 Dec;Volume 8, Issue 6, pp 385-389 Impact factor 3.186

Abstract: Conventional endoscopy can miss flat early gastric cancers (0-IIb) because they may not be visible. We treated a patient with synchronous flat early gastric cancers missed by conventional white-light endoscopy (WLE). A 74-year-old Japanese male was referred for endoscopic submucosal dissection (ESD) of a depressed-type early gastric cancer (0-IIc) on the posterior wall of the antrum. Linked color imaging (LCI) detected two flat reddish lesions (0-IIb) measuring 30 mm and 10 mm in diameter in the distal body and prepyloric area, respectively, which had not been detected by conventional WLE. LCI clearly demonstrated the line of demarcation between the malignant lesion and the surrounding mucosa without magnification. Flat early gastric cancers were suspected because both lesions had irregular surface patterns using magnifying blue laser imaging (BLI). An additional depressed lesion (0-IIc) was detected by laser WLE along the greater curvature in the antrum. Magnifying BLI suggested a malignant lesion. Histological examination of biopsy specimens revealed atypical glands in all four lesions. ESD of these lesions was performed. Pathological examination of the resected specimens confirmed well-differentiated adenocarcinoma localized to the mucosa in all four lesions. Flat early gastric cancers became clearly visible using new endoscopic technology.


Comparison of the diagnostic ability of blue laser imaging magnification versus pit pattern analysis for colorectal polyps.

Nakano A1, Hirooka Y2, etc

Endosc Int Open. 2017 Apr;5(4): Impact factor 5.196

Background and Aim: There have been few evaluations of the diagnostic ability of new narrow band light observation blue laser imaging (BLI). The present prospective study compared the diagnostic ability of BLI magnification and pit pattern analysis for colorectal polyps.

Patients and Methods: We collected lesions prospectively, and the analysis of images was made by two endoscopists, retrospectively. A total of 799 colorectal polyps were examined by BLI magnification and pit pattern analysis at Nagoya University Hospital. The Hiroshima narrow-band imaging classification was used for BLI. Differentiation of neoplastic from non-neoplastic lesions and diagnosis of deeply invasive submucosal cancer (dSM) were compared between BLI magnification and pit pattern analysis. Type C2 in the Hiroshima classification was evaluated separately, because application of this category as an index of the depth of cancer invasion was considered difficult.

Results: We analyzed 748 colorectal polyps, excluding 51 polyps that were inflammatory polyps, sessile serrated adenoma/polyps, serrated adenomas, advanced colorectal cancers, or other lesions. The accuracy of differential diagnosis between neoplastic and non-neoplastic lesions was 98.4 % using BLI magnification and 98.7 % with pit pattern analysis. In addition, the diagnostic accuracy of BLI magnification and pit pattern analysis for dSM for cancer was 89.5 % and 92.1 %, respectively. When type C2 lesions were excluded, the diagnostic accuracy of BLI for dSM was 95.9 %. The 18 type C2 lesions comprised 1 adenoma, 9 intramucosal or slightly invasive submucosal cancers, and 8 dSM. Pit pattern analysis allowed accurate diagnosis of the depth of invasion in 13 lesions (72.2 %).

Conclusion: Most colorectal polyps could be diagnosed accurately by BLI magnification without pit pattern analysis, but we should add pit pattern analysis for type C2 lesions in the Hiroshima classification.


Effect of novel bright image enhanced endoscopy using blue laser imaging (BLI).

Kaneko K, Oono Y, etc

Endosc Int Open. 2014 Dec;2(4): Impact factor 5.196

Background and Aim: The novel method of image-enhanced endoscopy (IEE) named blue laser imaging (BLI) can enhance the contrast of surface vessels using lasers for light illumination. BLI has two IEE modes: high contrast mode (BLI-contrast) for use with magnification, and bright mode (BLI-bright), which achieves a brighter image than BLI-contrast and yet maintains the enhanced visualization of vascular contrast that is expected for the detection of tumors from a far field of view. The aim of this study is to clarify the effect of BLI-bright with a far field of view compared to BLI-contrast and commonly available narrow-band imaging (NBI).

Patients and Methods: Patients with neoplasia, including early cancer in the pharynx, esophagus, stomach, or colorectum, were recruited and underwent tandem endoscopy with BLI and NBI systems. Six sets of images of the lesions were captured with a changing observable distance from 3 to 40 mm. Individual sets of images taken from various observable distances were assessed for visibility among BLI-bright, BLI-contrast, and NBI modes. The brightness and contrast of these images were also analyzed quantitatively.

Results: Of 51 patients, 39 were assessed. Image analysis indicated that only BLI-bright maintained adequate brightness and contrast up to 40 mm and had significantly longer observable distances compared to the other methods. Furthermore, BLI-bright enhanced the visualization of serious lesions infiltrating into deeper layers, such as esophageal lamina propria or gastric submucosal cancers.

Conclusion: BLI-bright will be a helpful tool for the far-field view with IEE in organs with wider internal spaces such as the stomach.


The adenoma miss rate of blue-laser imaging vs. white-light imaging during colonoscopy: a randomized tandem trial.

Shimoda R, Sakata Y et al

Endoscopy. 2017 Feb;49(2):186-190.

Background/Aim: The aim of the present study was to determine whether blue-laser imaging (BLI) reduced the miss rate of colon adenomatous lesions compared with conventional white-light imaging (WLI).

Patients/Methods: This was a prospective randomized study of patients undergoing screening and/or surveillance colonoscopy at Saga Medical School, Japan. A total of 127 patients were randomized to tandem colonoscopy with BLI followed by WLI (BLI-WLI group) or WLI followed by WLI (WLI-WLI group). The main outcome measure was the adenoma miss rate.

Results: The proportion of patients with adenomatous lesions was 62.5 % (40 /64) in the BLI-WLI group and 63.5 % (40 /63) in the WLI-WLI group. The total number of adenomatous lesions detected in the first inspection of the BLI-WLI and WLI-WLI groups was 179 and 108, respectively, compared with 182 and 120 in the second inspection, respectively. The miss rate in the BLI-WLI group was (1.6 %), which was significantly less than that in the WLI-WLI group (10.0 %, P = 0.001).

Conclusion: Colonoscopy using BLI resulted in a lower colon adenoma miss rate than WLI.

BLI study pdf


Diagnostic ability of magnifying endoscopy with blue laser imaging for early gastric cancer: a prospective study.

Dohi O, Yagi N et all,

Gastric Cancer. 2016 Jun 13.

Background: Blue laser imaging (BLI) is a new image-enhanced endoscopy technique that utilizes a laser light source developed for narrow-band light observation. The aim of this study was to evaluate the usefulness of BLI for the diagnosis of early gastric cancer.

Methods: This single center prospective study analyzed 530 patients. The patients were examined with both conventional endoscopy with white-light imaging (C-WLI) and magnifying endoscopy with BLI (M-BLI) at Kyoto Prefectural University of Medicine between November 2012 and March 2015. The diagnostic criteria for gastric cancer using M-BLI included an irregular microvascular pattern and/or irregular microsurface pattern, with a demarcation line according to the vessel plus surface classification system. Biopsies of the lesions were taken after C-WLI and M-BLI observation. The primary end point of this study was to compare the diagnostic performance between C-WLI and M-BLI.

Results: We analyzed 127 detected lesions (32 cancers and 95 non-cancers). The accuracy, sensitivity, and specificity of M-BLI diagnoses were 92.1, 93.8, and 91.6 %, respectively. On the other hand, the accuracy, sensitivity, and specificity of C-WLI diagnoses were 71.7, 46.9, and 80.0 %, respectively.

Conclusions: M-BLI had improved diagnostic performance for early gastric cancer compared with C-WLI. These results suggested that the diagnostic effectiveness of M-BLI is similar to that of magnifying endoscopy with narrowband imaging (M-NBI).


Endoscopic features of lymphoid follicles using Blue Laser Imaging (BLI) endoscopy in the colorectum and its association with chronic bowel symptoms in healthy subjects

Tahara T, Okubo M, et al

Gastrointestinal Endoscopy volume 83, 2016

Background/Aim: In the colorectum, lymphoid follicles hyperplasia (LH) are sometimes observed as small, round, yellowish-white nodules. The novel imageenhanced endoscopy system named blue laser imaging (BLI) provides enhanced the contrast of surface vessels using lasers for light illumination. The aim of the present study was to investigate endoscopic features of LH observed by BLI endoscopy and its association with chronic bowel symptoms in
healthy subjects.

Patients/ Methods: 300 healthy participants (median age: 60 years, male/ female: 180/120) undergoing screening colonoscopy were enrolled. After inserting colonoscope in to the cecum, entire colorectum was observed by using BLI-bright mode with non-magnification view. LH was defined as well demarcated white nodules. In particular, elevated LH with erythema was distinguished as LH high.

Results: LHs are observed more clearly by using BLI-bright mode than white light. LHs were histologically confirmed as intense infiltration of lymphocytes or plasmacytes. LH was observed in 134 subjects (44.6%). Among them, 67 (22.3%) was LH high. LH was associated younger age (Odds ratio (OR) = 1.05, 95%Confidence Interval (95%CI) = 1.03-1.07, P<0.0001). The location of LH was 25.3%, 37.7%, 15.3%, 14% 16.7%, and 15.7% in the cecum, ascending colon transverse colon, descending colon, sigmoid colon and rectum, respectively. The presence of LH was significantly associated with chronic bowel symptoms including constipation, hard stools, diarrhea and loose stools (all LH: OR=4.03, 95%CI=2.36-6.89, P<0.0001, LH high: OR=5.31, 95%CI=2.64-10.71, P<0.0001). LH high was closely associated with both constipation associated symptoms (OR=3.94, 95%CI=1.79-8.66, P=0.0007) and diarrhea associated symptoms (OR=5.22, 95%CI=2.09-13.05, P=0.0004) . In particular, LH high in the ascending colon was strongly associated with bowel symptoms (P<0.0001).

Conclusion: LH, visualized by using BLI endoscopy was associated with bowel symptom, raising the possibility of pathogenic role of this endoscopic finding in the functional lower gastrointestinal disorders.


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.)


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.