Tu1468 Magnifying the Endoscopic Characteristics of Colorectal Lesions With Narrow Band Imaging System

Abstract

who each evaluated at least 25 colorectal polyps by HD i-scan participated. All small colorectal polyps were examined using HD white-light followed by HD i-scan, then classified into adenomatous or non-adenomatous with a high-or low level of confidence, and subsequently removed and sent for histopathologic examination. Distal colon was defined as rectosigmoid whereas proximal colon was defined as proximal to the rectosigmoid. Sensitivity, specificity, positive, negative predictive value and accuracy with corresponding 95% confidence intervals for prediction of histopathology were calculated. The agreement between surveillance recommendations that would follow optical diagnosis for small colorectal polyps combined with histopathology assessment of the remaining polyps versus histopathology assessment alone was calculated. Results: A total of 309 small colorectal polyps from 93 patients were examined. Of them, 295 (95.5%) were predicted with high-confidence and hence, included in the final analyses. Of these, 110 (37.3%) were located in the distal colon of which 33 (30%) were adenomatous and 77 (70%) non-adenomatous. Diagnostic performances of the endoscopists are depicted in the Table. The negative predictive value for adenoma histology of all small colonic polyps was 87% and increased to 97% for small distal polyps only. In addition, the agreement between surveillance recommendations by formal histopathology versus HD iscan analysis of all small colonic polyps was 81% and increased to 94% for small distal polyps only (Table). Of note, the 6% disagreement reflects patients receiving surveillance earlier than recommended by histopathology alone. Conclusion: Our data indicate that optical diagnosis of small rectosigmoid polyps using HD i-scan is already feasible in the routine practice, with a negative predictive value of 97% and 94% agreement of surveillance recommendations. However, prediction of histology in proximal polyps is only moderate, emphasizing the need for continuous training.