High definition plus colonoscopy combined with i-scan tone enhancement vs. high definition colonoscopy for colorectal neoplasia: A randomized trial

Dig Liver Dis. 2014 Nov;46(11):991-6. doi: 10.1016/j.dld.2014.07.169. Epub 2014 Aug 20.


Background: High definition endoscopy is the accepted standard in colonoscopy. However, an important problem is missed polyps.

Aims: Our objective was to assess the additional adenoma detection rate between high definition colonoscopy with tone enhancement (digital chromoendoscopy) vs. white light high definition colonoscopy.

Methods: In this prospective randomized trial patients were included to undergo a tandem colonoscopy. The first exam was a white light colonoscopy with removal of all visualized polyps. The second examination was randomly assigned in a 1:1 ratio as either again white light colonoscopy (Group A) or colonoscopy with tone enhancement (Group B). Primary endpoint was the adenoma detection rate during the second withdrawal (sample size calculation - 40 per group).

Results: 67 lesions (Group A: n=34 vs. Group B: n=33) in 80 patients (mean age 61 years, male 64%) were identified on the first colonoscopy. The second colonoscopy detected 78 additional lesions: n=60 with tone enhancement vs. n=18 with white light endoscopy (p<0.001). Tone enhancement found more additional adenomas (A n=20 vs. B n=6, p=0.006) and identified significantly more missed adenomas per subject (0.5 vs. 0.15, p=0.006).

Conclusions: High definition plus colonoscopy with tone enhancement detected more adenomas missed by white light colonoscopy.

Keywords: Adenoma detection rate; Adenoma miss rate; I-scan technique; Red flag technology.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adenocarcinoma / diagnosis*
  • Adenocarcinoma / surgery
  • Adult
  • Aged
  • Chi-Square Distribution
  • Colonoscopy / methods*
  • Colorectal Neoplasms / diagnosis*
  • Colorectal Neoplasms / surgery
  • Female
  • Germany
  • Hospitals, University
  • Humans
  • Image Enhancement / methods
  • Image Interpretation, Computer-Assisted / methods*
  • Logistic Models
  • Male
  • Middle Aged
  • Prospective Studies
  • Sensitivity and Specificity
  • Signal Processing, Computer-Assisted*
  • Statistics, Nonparametric