Many reports have demonstrated the efficacy of narrow band imaging (NBI) with magnification in predicting the histology and invasion depth of colorectal polyps. In China, however, the magnifying endoscope is not used in some medical centers. Even in centers equipped with this technique, the magnifying colonoscope is not sufficiently used in daily practice. Recently, a simple category classification (NICE classification) using non-magnified NBI has been proposed, which classifies colorectal tumors into types 1-3 based on different characteristics of color, surface pattern, and microvessels. Type-1 is considered an index for hyperplastic lesions, type-2 is an index for adenoma or mucosal/SM scanty invasive carcinoma and type-3 is an index for deep SM invasive carcinoma. The new classification has soon arouse attention and been validated in some centers on the efficacy of differentiating adenomatous and hyperplastic polyps. However, most studies enrolled diminutive polyps less than 5mm and the efficacy of non-magnified NBI in differentiating type-2 and type-3 lesions has not been reported. To promote this simple classification, we design this multicenter study to evaluate the predictive validity and performance characteristics of the non-magnified NBI in diagnosing polyps during both image and real-time process.
Recently, a new category classification (NICE classification) using non-magnified NBI has been proposed. We design this multicenter study to evaluate the reliability and validity of the NICE classification in diagnosing colorectal polyps by Chinese endoscopists during both image and real-time process.