Magnifying endoscopy with narrow band imaging for diagnosis of colorectal tumors

Abstract

Narrow band imaging (NBI) uses optical filters for red-green-blue sequential illumination and narrows the bandwidth of spectral transmittance. This study aimed to clarify the clinical usefulness of NBI magnification in assessment of pit patterns for diagnosis of colorectal tumors. This was a retrospective study. Department of Endoscopy, Hiroshima University Hospital. A total of 148 colorectal lesions, 16 hyperplasias, 84 tubular adenomas, and 48 early carcinomas were examined and diagnosed histologically. Mean size of lesions was 15.6+/-7.28 mm. Lesions were observed first under NBI magnification without chromoendoscopy and then under standard magnification with chromoendoscopy, and pit patterns were recorded. Results of NBI magnification were compared with those of standard magnification with chromoendoscopy to assess the clinical usefulness of NBI magnification for diagnosing colorectal neoplasia. Correspondence between the two diagnostic methods was 88% (14/16) for type II, 100% (2/2) for type IIIs, 98% (73/75) for type IIIl, 88% (7/8) for type IV, 78% (25/32) for type Vi, and 100% (3/3) for type Vn pit patterns. NBI depicted brownish change on the basis of surface capillaries in 6% (1/16) of hyperplasia and 99% (83/84) of tubular adenomas. This difference in color depiction was significant. This study was performed in single center. Determination of pit patterns of colorectal neoplasias by NBI magnification was nearly the same as that by standard magnification with chromoendoscopy. Furthermore, NBI can distinguish neoplastic and nonneoplastic lesions without chromoendoscopy.