Magnified Observation of Microvascular Architecture Using Narrow Band Imaging (NBI) for the Differential Diagnosis Between Non-Neoplastic and Neoplastic Colorectal Lesion.

摘要

Background: In 1999, we developed a prototype NBI system and have reported the observation of surface structure (pit pattern) using the NBI colonoscopy to be useful for differentiating neoplasia from non-neoplasia (Endoscopy, 2004). Recently, we described how the presence of "meshed brown capillary (MC) vessels" arranged in a honeycomb pattern around the mucosal glands on NBI colonoscopy is also useful for differential diagnosis without the application of any dye solution (Dig Endosc, 2005). Aim: The aim of this prospective study is to clarify the clinical usefulness of the observation of MC vessels for distinguishing between non-neoplastic and neoplastic lesions. Method: Eligibility criteria: Patients who underwent total colonoscopy using NBI colonoscopy between Sep. 2004 and Dec. 2004 were recruited for this prospective study. Exclusion criteria: Patients with i) colorectal lesions with previous evaluation including histology or colonoscopy, ii) obviously invasive carcinoma, iii) polyps larger than 10 mm, and iv) IBD, HNPCC and FAP were excluded. The detected lesions were classified into the following two groups according to their capillary patterns using NBI colonoscopy with magnification: neoplastic for lesions with positive MC vessels and non-neoplastic for lesions without MC vessels. For histological examinations, the lesions finally diagnosed as non-neoplastic were subjected to biopsy and those as neoplastic were removed endoscopically. The accuracy rates of endoscopic diagnosis were evaluated by referring to the final pathological diagnosis. Results: Of 702 patients recruited in this study, 453 patients with no polyps were found on colonoscopy 157 patients were ineligible according to the exclusion criteria [reason for exclusion: i) 68, ii) 39, iii) 41, and iv) 4 patients]. 5 polyps in 5 patients were unretrievable. The remaining 92 patients were enrolled. 150 colorectal lesions including 39 hyperplastic polyps and 111 adenomatous lesions were detected and evaluated on histology. The mean size of identified lesions was 3.8 mm (range: 2-10 mm). The overall diagnostic accuracy, sensitivity, and-specificity using the presence of MC vessels for distinction between neoplastic and non-neoplastic lesions was 95.3% (143/150), 96.4% (107/111) and 92.3% (36/39), respectively (p < 0.0001). Conclusion: Magnification using NBI colonoscopy for the observation of the presence of MC vessels is extremely useful for distinguishing between non-neoplastic and neoplastic lesions without the application of any dye solution. These results suggest that NBI colonoscopy as "optical chromoendoscopy" allows for simpler and more efficient screening colonoscopy.