Evaluation Of Microvessels In Colorectal Tumors By Narrow Band Imaging (Nbi) Magnification Colonoscopy

Background: Narrow band imaging (NBI) uses optical filters for sequential red-green-blue illumination and narrows the bandwidth of spectral transmittance. The aim of this study is determine the clinical usefulness of NBI magnification for evaluation of microvascular architecture and qualitative diagnosis of colorectal tumors. Materials and Methods: A total of 189 colorectal lesions were analyzed. Each lesion was observed by NBI magnifying endoscopy and classified according to microvascular features (i.e., thickness and irregularity). Capillary thickness was classified as invisible, thin, or thick, and capillary irregularity was classified as invisible, regular, mildly irregular, or severely irregular. NBI endoscopic images were compared to histologic findings. Results: With respect to capillary thickness, invisible capillaries was found significantly often in hyperplasia (HP) lesions, and thick capillaries was found significantly often in carcinoma with submucosal massive invasion (sm-m) (p < 0.01). With respect to capillary irregularity, invisible capillaries was found significantly often in HP lesions, and severely irregular capillaries was found significantly often in sm-m lesions (p < 0.01). Accuracy of diagnosis of sm-m on the basis of thick and severely irregular lesions was 100%. Conclusion: Microvascular features determined by NBI magnification are associated with histologic grade and depth of submucosal invasion. These results indicate that NBI magnification is useful for prediction of histology and selection of therapeutic strategies of colorectal tumors.