Value of magnifying endoscopy in classifying colorectal polyps based on vascular pattern

Background and study aims: Narrow-band imaging (NBI) has been developed as a new technique to differentiate tissue patterns in vivo. The aim of this study was to evaluate the diagnostic accuracy of NBI endoscopy with and without high magnification for the differentiation of neoplastic from non-neoplastic colorectal polyps.

Patients and methods: Among 200 colorectal polyps from 131 patients, 100 lesions were classified according to vascular patterns by NBI endoscopy with high optical magnification and 100 lesions by high-definition endoscopy without high magnification. Additionally, the clarity of the vessel network was assessed. Histologic analysis was performed on all lesions.

Results: NBI endoscopy with high magnification resulted in a sensitivity of 92.1 % and a specificity of 89.2 % for the differentiation of neoplastic versus non-neoplastic lesions. This performance was statistically comparable to high-definition NBI endoscopy without high magnification, which showed a sensitivity of 87.9 % and specificity of 90.5 %. However, vessel network was significantly better visualized by NBI endoscopy with optical magnification compared with high-definition NBI endoscopy without high magnification. In comparison with NBI endoscopy, white-light endoscopy, with or without magnification, resulted in inferior discrimination between neoplastic and non-neoplastic polyps.

Conclusion: The results demonstrate that the superior visibility of capillary vessels by the NBI technique allows the evaluation of colorectal lesions – based on the vascular patterns – with high diagnostic accuracy. In clinical routine, high-definition NBI endoscopy without high magnification may be used to sufficiently predict colorectal polyp histology, and high magnification can additionally facilitate visualization of vascular networks.

References

• 1 Vogelstein B, Fearon E R, Hamilton S R. et al . Genetic alterations during colorectal-tumor development.  N Engl J Med. 1988;  319 525-532
• 2 Winawer S J, Zauber A G, Ho M N. et al . Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup.  N Engl J Med. 1993;  329 1977-1981
• 3 Levin T R, Zhao W, Conell C. et al . Complications of colonoscopy in an integrated health care delivery system.  Ann Intern Med. 2006;  145 880-886
• 4 Kudo S, Tamura S, Nakajima T. et al . Diagnosis of colorectal tumorous lesions by magnifying endoscopy.  Gastrointest Endosc. 1996;  44 8-14
• 5 Gono K, Obi T, Yamaguchi M. et al . Appearance of enhanced tissue features in narrow-band endoscopic imaging.  J Biomed Opt. 2004;  9 568-577
• 6 Tischendorf J JW, Wasmuth H E, Koch A. et al . Value of magnifying chromoendoscopy and narrow band imaging (NBI) in classifying colorectal polyps: a prospective controlled study.  Endoscopy. 2007;  39 1092-1096
• 7 Chiu H M, Chang C Y, Chen C C. et al . A prospective comparative study of narrow-band imaging, chromoendoscopy, and conventional colonoscopy in the diagnosis of colorectal neoplasia.  Gut. 2007;  56 373-379
• 8 East J E, Suzuki N, Bassett P. et al . Narrow band imaging with magnification for the characterization of small and diminutive colonic polyps: pit pattern and vascular pattern intensity.  Endoscopy. 2008;  40 811-817
• 9 Su M Y, Hsu C M, Ho Y P. et al . Comparative study of conventional colonoscopy, chromoendoscopy, and narrow-band imaging systems in differential diagnosis of neoplastic and nonneoplastic colonic polyps.  Am J Gastroenterol. 2006;  101 2711-2716
• 10 Rogart J N, Jain D, Siddiqui U D. et al . Narrow-band imaging without high magnification to differentiate polyps during real-time colonoscopy: improvement with experience.  Gastrointest Endosc. 2008;  68 1136-1145
• 11 Sikka S, Ringold D A, Jonnalagadda S, Banerjee B. Comparison of white light and narrow band high definition images in predicting colon polyp histology, using standard colonoscopes without optical magnification.  Endoscopy. 2008;  40 818-822
• 12 Soetikno R M, Kaltenbach T, Rouse R V. et al . Prevalence of nonpolypoid (flat and depressed) colorectal neoplasms in asymptomatic and symptomatic adults.  JAMA. 2008;  299 1027-1035
• 13 Rastogi A, Bansal A, Wani S. et al . Narrow-band imaging colonoscopy – a pilot feasibility study for the detection of polyps and correlation of surface patterns with polyp histologic diagnosis.  Gastrointest Endosc. 2008;  67 280-286
• 14 Rastogi A, Pondugula K, Bansal A. et al . Recognition of surface mucosal and vascular patterns of colon polyps by using narrow-band imaging: interobserver and intraobserver agreement and prediction of polyp histology.  Gastrointest Endosc. 2009;  69(3 Suppl) 716-722
• 15 Rex D K. Narrow-band imaging without optical magnification for histologic analysis of colorectal polyps.  Gastroenterology. 2009;  136 1174-1181
• 16 Bond J H. Clinical relevance of the small colorectal polyp.  Endoscopy. 2001;  33 454-457
• 17 Barclay R L, Vicari J J, Doughty A S. et al . Colonoscopic withdrawal times and adenoma detection during screening colonoscopy.  N Engl J Med. 2006;  355 2533-2541