Purpose: The presence of meshed capillary (MC) vessels has been shown to be highly sensitive (96%) and specific (92%) for diagnosing colorectal neoplasia on colonoscopy using narrow-band imaging (NBI) with optical magnification (mag), which is not available in North America (Sano Y et al. GIE 2009). However, a MC pattern found on NBI without optical mag may still enable diagnosis of colorectal neoplasia. The aim of this study was to determine the diagnostic capabilities of NBI colonoscopy without optical mag in identifying neoplastic colorectal polyps. Methods: Colorectal polyps found on white-light colonoscopy were studied using NBI with 1.5x zoom, but without true optical mag. The MC pattern was assessed, and then polyps were resected for pathological analysis. A highdefinition (hi-def) colonoscope (CFH180AL, Olympus America, Center Valley, PA) was used with a processor capable of NBI and hi-def imaging (Exera II, Olympus America). All procedures were performed or supervised by one experienced GI endoscopist (AYW) trained in NBI.Table: Table. Diagnostic characteristics by polyp sizeResults: 52 patients (33 men, 19 women) with a median age of 59.5 years (range: 34-84 years) were diagnosed with 126 colorectal polyps with a median size of 3mm (range: 2-30 mm). Polyps were located in the cecum (n=12), ascending (n=24), hepatic (n=5), transverse (n=17), descending (n=11), sigmoid (n=24), rectosigmoid colon (n=12), and rectum (n=21). Polyp morphology consisted of Paris classification type 0-Is (n=30), 0-Ip (n=7), 0-IIa (n=82), 0-IIb (n=1), 0-IIa+IIc (n=3), 0-IIa+Is (n=1), type 1 (n=1), type 3 (n=1). Post-polypectomy pathology consisted of adenocarcinoma (n=2), squamous cell carcinoma (n=1), TVA (n=3), adenoma (n=61), inflammatory (n=3), hyperplastic (n=49), and normal mucosa (n=7). 69 of the 126 polyps were MC positive on NBI suggesting neoplasia, whereas 57 were MC negative suggesting non-neoplasia. Final pathology found that seven non-neoplastic polyps were misdiagnosed as MC positive (hyperplastic, n=6; inflammatory, n=1) and five adenomas were misdiagnosed as being MC negative. For all polyps studied, the MC pattern using NBI without optical mag had a sensitivity of 92.5%, specificity of 88.1%, PPV of 89.9%, NPV of 91.2%, and accuracy of 90.5% for diagnosing neoplasia. Refer to the table for analysis by polyp size. Conclusion: Use of the MC pattern on NBI colonoscopy without optical mag effectively distinguishes neoplastic from non-neoplastic colorectal polyps. Sensitivity of the MC pattern for neoplastic polyps is better for polyps >5 mm, but remains high in polyps ≤5 mm in size. NBI colonoscopy without optical mag for neoplastic polyp diagnosis appears to be comparable to that of NBI with optical mag when the MC pattern is used. A large prospective trial is needed for further validation. Disclosure: Dr Henry - no conflict of interest or relevant disclosures. Dr Yeaton consultant for Olympus and Gore. Dr Shami - consultant for Olympus. Dr Kahaleh grant support from Boston Scientific, Olympus, Alveolus, Conmed, and Cook Medical. Dr Peura - no conflict of interest or relevant disclosures. Dr Emura - consultant for Olympus. Dr Wang - no conflict of interest or relevant disclosures.