DIAGNOSIS OF COLORECTAL TUMORS USING BLUE LASER IMAGING

Abstract

A new endoscope system, “LASEREO”, developed by Fujifilm uses a semiconductor laser as the light source. It has the narrow-band light observation function, which is named Blue laser imaging (BLI), without a customized optical filter. The LASEREO system has 2 kinds of lasers whose wavelengths are 410 nm and 450 nm. Additionally, both of the bandwidths are less than about 2 nm, compared to the bandwidth of narrow band imaging (NBI) of 30 nm. The BLI mode allows us to see detailed vessels and clear surface patterns. By controlling the power of the 2 lasers, a “BLI-bright” mode can be set and this mode is brighter than the BLI mode, and it is expected to be useful for tumor detection. We have already reported the efficacy of BLI magnification for diagnosis of neoplastic tumors using the NBI classification such as Sano classification and Hiroshima classification in the multicenter study. Moreover, we have also reported the efficacy of BLI for diagnosis of non-neoplastic and neoplastic colorectal lesions. The diagnostic accuracy of BLI magnification was 84.3% (265/314). Additionally, the diagnostic accuracy was higher for polyps <20 mm in diameter than for polyps ≥20 mm in diameter (92.1% vs. 72.5% ; P=0.000003 [<0.001]). In view of morphology, the diagnostic accuracy was significantly lower for superficial polyps ≥20 mm in diameter than for superficial polyps <20 mm in diameter (70.0% vs. 82.9% ; P=0.03 <0.05). As a technical aspect for diagnosing colorectal lesions, BLI magnification allows better detection of surface pattern compared with NBI.