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Original article
Narrow band imaging to differentiate neoplastic and non-neoplastic colorectal polyps in real time: a meta-analysis of diagnostic operating characteristics
  1. Sarah K McGill1,
  2. Evangelos Evangelou2,
  3. John P A Ioannidis3,
  4. Roy M Soetikno1,
  5. Tonya Kaltenbach1
  1. 1Gastroenterology Section, Veterans Affairs Palo Alto, and Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA
  2. 2Department of Hygiene and Epidemiology, School of Medicine of the University of Ioannina, Ioannina, Epirus, Greece
  3. 3Department of Statistics, Stanford University School of Humanities and Sciences, and Stanford Prevention Research Center, School of Medicine, Stanford, California, USA
  1. Correspondence to Dr. Tonya Kaltenbach, Gastroenterology Section, Veterans Affairs Palo Alto, 3801 Miranda Ave, GI111, Palo Alto, CA 94304, USA; endoresection{at}


Purpose Many studies have reported on the use of narrow band imaging (NBI) colonoscopy to differentiate neoplastic from non-neoplastic colorectal polyps. It has potential to replace pathological diagnosis of diminutive polyps. We aimed to perform a systematic review and meta-analysis on the real-time diagnostic operating characteristics of NBI colonoscopy.

Methods We searched PubMed, SCOPUS and Cochrane databases and abstracts. We used a two-level bivariate meta-analysis following a random effects model to summarise the data and fit hierarchical summary receiver-operating characteristic (HSROC) curves. The area under the HSROC curve serves as an indicator of the diagnostic test strength. We calculated summary sensitivity, specificity and negative predictive value (NPV). We assessed agreement of surveillance interval recommendations based on endoscopic diagnosis compared to pathology.

Results For NBI diagnosis of colorectal polyps, the area under the HSROC curve was 0.92 (95% CI 0.90 to 0.94), based on 28 studies involving 6280 polyps in 4053 patients. The overall sensitivity was 91.0% (95% CI 87.6% to 93.5%) and specificity was 82.6% (95% CI 79.0% to 85.7%). In eight studies (n=2146 polyps) that used high-confidence diagnostic predictions, sensitivity was 93.8% and specificity was 83.3%. The NPVs exceeded 90% when 60% or less of all polyps were neoplastic. Surveillance intervals based on endoscopic diagnosis agreed with those based on pathology in 92.6% of patients (95% CI 87.9% to 96.3%).

Conclusions NBI diagnosis of colorectal polyps is highly accurate—the area under the HSROC curve exceeds 0.90. High-confidence predictions provide >90% sensitivity and NPV. It shows high potential for real-time endoscopic diagnosis.

  • Colonic Polyps
  • Colorectal Neoplasia
  • Colorectal Cancer Screening
  • Meta-Analysis
  • Colonoscopy

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