Time saving with narrow-band imaging for distinguishing between neoplastic and non-neoplastic small colorectal lesions

J Gastroenterol Hepatol. 2012 Feb;27(2):351-5. doi: 10.1111/j.1440-1746.2011.06854.x.


Background and aims: For colonoscopic examinations, the narrow-band imaging (NBI) system is more convenient and timesaving than magnifying chromoendoscopy (MCE). However, the time-saving aspects of NBI techniques have not been assessed. The present study compared interpretation times between NBI and MCE techniques in distinguishing between neoplastic and non-neoplastic small colorectal lesions.

Methods: Between January and March 2010, 693 consecutive patients who underwent colonoscopy at the National Cancer Center Hospital, Tokyo, Japan, were enrolled. When the first lesion was detected by conventional white-light observation, the patient was randomly assigned to undergo a sequence of NBI and MCE observations (group A: NBI-MCE, group B: MCE-NBI). The time to diagnosis with each modality (NBI, from changing to NBI until diagnosis; MCE, from the start of indigo carmine solution spraying until diagnosis) was recorded by an independent observer. The sensitivity, specificity, and diagnostic accuracy of the first modality used in each group (NBI or MCE) were assessed by referring to the histopathological data.

Results: Seventy-one patients with 137 lesions were randomized to group A, and 80 patients with 163 lesions to group B. The median interpretation times were 12 s (interquartile range [IQR]: 7-19 s) in group A, and 17 s (IQR: 12-24 s) in group B, the difference being significant (P < 0.001). No significant differences were observed between NBI and MCE in terms of sensitivity, specificity, and diagnostic accuracy.

Conclusions: NBI reduces the interpretation times for distinguishing between neoplastic and non-neoplastic small lesions during colonoscopies, without loss of diagnostic accuracy.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Chi-Square Distribution
  • Colon / pathology*
  • Colonic Polyps / diagnosis*
  • Colonic Polyps / pathology
  • Colonoscopy / methods*
  • Colorectal Neoplasms / diagnosis*
  • Colorectal Neoplasms / pathology
  • Coloring Agents*
  • Diagnosis, Differential
  • Female
  • Humans
  • Image Enhancement
  • Indigo Carmine*
  • Japan
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • Rectum / pathology*
  • Sensitivity and Specificity
  • Time Factors
  • Tumor Burden


  • Coloring Agents
  • Indigo Carmine