Vascular pattern classification of colorectal lesions with narrow band imaging magnifying endoscopy.

Magnifying narrow band imaging (NBI) has enabled to observe the vascular pattern of colorectal lesions. Their broad findings have been divided into six groups according to endoscopical vascular features: normal, faint, network, dense, irregular and sparse. Most hyperplastic polyps show a faint pattern. The vascular patterns of adenomas are mainly network or dense ones. The predominant vascular patterns of cancer were irregular and sparse. Indeed, irregular pattern has found to be characteristic for protruded or flat-elevated cancer, whereas sparse pattern unique for depressed cancer. Through NBI, neoplastic lesions could be differentiated from those non-neoplastic with sensitivity of 83.5%, specificity of 98.7% and accuracy of 98.2%. It was able to distinguish between massively submucosal invasive cancers and slightly submucosal invasive cancers by using the vascular pattern with 91.0% sensitivity and 79.4% specificity. The overall accuracy was 88.3%. NBI system has showed to be a valuable technique for distinguishing neoplastic from non-neoplastic lesions, as well as massively from slightly submucosal invasive cancer. Therefore, vascular pattern analysis might be a promising tool for determining treatment selection, whether endoscopical or surgically.