Assessment of colorectal lesions using magnifying colonoscopy and mucosal dye spraying: Can significant lesions be distinguished?

Background and Study Aims: Assessing the nature of lesions at the time of c olonoscopy is important, and magnifying colonoscopy allows examination of m ucosal crypt patterns. In this study, we assessed mucosal crypt patterns to see whether we could predict the histological findings. Patients and Methods: This retrospective study of total colonoscopy using m agnifying colonoscopy involved 4445 patients between December 1993 and July 1998 at the National Cancer Center Hospital East. The mucosal crypt patter ns of 3438 lesions were observed under magnifying colonoscopy with 0.2 % in digo carmine solution, and classified according to a modified Kudo classifi cation (type I to V). After endoscopic or surgical resection (3291 eases an d 147 cases, respectively), histopathological examination was performed. Results: The diagnostic accuracy of magnifying endoscopy for non-neoplastic lesions was 75 % (117/157), for adenomatous polyps it was 94% (3006/3186), and for invasive carcinomas it was 85 % (81/95). Conclusions: The combination of magnifying colonoscopy and dye spraying is helpful in determining the nature of colonic Lesions as non-neoplastic, ade nomas, or invasive carcinomas. Therefore it may be possible to determine, a t the time of colonoscopy, which lesions require no treatment, which can be removed endoscopically, and which should be removed by surgery.