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.

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.

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.

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.

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