Prospective, randomized, back-to-back trial evaluating the usefulness of i-SCAN in screening colonoscopy

Gastrointest Endosc. 2012 May;75(5):1011-1021.e2. doi: 10.1016/j.gie.2011.11.040. Epub 2012 Feb 28.


Background: The newly developed i-SCAN application can theoretically maximize the effectiveness of colonoscopy. However, the practical usefulness of the i-SCAN application during screening colonoscopy has not been assessed.

Objective: To assess the efficacy of the i-SCAN application during screening colonoscopy.

Design: A prospective, randomized trial that used a modified, back-to-back colonoscopy.

Setting: Academic hospital.

Patients: This study involved 389 asymptomatic, consecutive, average-risk patients who underwent screening colonoscopy.

Intervention: The patients were randomized to the first withdrawal with either conventional high-definition white light (HDWL group; n = 119), i-SCAN contrast/surface enhancement (CE/SE) mode (i-SCAN1 group; n = 115), or i-SCAN CE/SE/tone enhancement-colorectal mode (i-SCAN2 group; n = 118). All patients underwent a second examination with HDWL as the criterion standard.

Main outcome measurements: The primary outcome measurement was the adenoma detection rate and adenoma miss rate. The secondary outcome measurement was the accuracy of the histologic prediction of neoplastic and nonneoplastic polyps.

Results: The adenoma detection rates during the first withdrawal of HDWL, i-SCAN1, and i-SCAN2 were 31.9%, 36.5%, and 33.1%, respectively (P = .742), and the adenoma miss rates of each group were 22.9%, 19.3%, and 15.9%, respectively (P = .513). Based on the multivariate analysis, the application of i-SCAN was not associated with an improvement in adenoma detection and the prevention of missed polyps. However, the prediction of neoplastic and nonneoplastic colorectal lesions was more precise in the i-SCAN2 group compared with the HDWL group (accuracy 79.3% vs 75.5%, P = .029; sensitivity 86.5% vs 72.6%, P = .020; and specificity 91.4% vs 80.6%, P = .040).

Limitations: Single-center trial.

Conclusion: i-SCAN during the screening colonoscopy may fail to improve adenoma detection and the prevention of missed polyps, but i-SCAN appears to be effective for real-time histologic prediction of polyps compared with conventional HDWL colonoscopy. (

Clinical trial registration number: NCT01417611.).

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / diagnosis*
  • Adult
  • Colonic Neoplasms / diagnosis*
  • Colonic Polyps / pathology*
  • Colonoscopy / methods*
  • Early Detection of Cancer / methods*
  • Female
  • Humans
  • Image Enhancement*
  • Image Interpretation, Computer-Assisted
  • Logistic Models
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Predictive Value of Tests

Associated data