Concordance Between Pan-Intestinal Capsule Endoscopy and Colonoscopy for the Detection and Characterization of Colonic Lesions: Post Hoc Analysis on the Impact of Colonic Transit Time.

INTRODUCTION

Pan-intestinal capsule endoscopy (PCE) is increasingly used as a minimally invasive alternative to colonoscopy in the evaluation of mid- and lower gastrointestinal bleeding (MLGIB). However, the impact of colonic transit time (CTT) on diagnostic performance remains insufficiently characterized. This study aims to assess the concordance between PCE and colonoscopy for colorectal lesions and to determine whether CTT influences diagnostic accuracy.

METHODS

This post hoc analysis of a prospective single-center trial included patients with suspected MLGIB who underwent PCE followed by same-day colonoscopy. Only complete examinations were analyzed (n = 76). CTT was evaluated using predefined thresholds (≤ 60, ≤ 90, ≤ 120, and > 120 min). Diagnostic performance for vascular polypoid lesions and clinically significant polyps (≥ 6 mm; ≥ 10 mm) was calculated using colonoscopy as the reference standard.

RESULTS

Overall agreement between PCE and colonoscopy was moderate for vascular lesions (κ = 0.56) and polypoid lesions (κ = 0.51), substantial for polyps ≥ 6 mm (κ = 0.67), and near perfect for polyps ≥ 10 mm (κ = 0.88). Longer CTT was consistently associated with improved detection of polypoid lesions. Sensitivity for polyps ≥ 6 mm increased from 33.3% (CTT ≤ 90 min) to 83.3% (CTT > 90 min), with corresponding κ values rising from 0.34 to 0.81. Detection of vascular lesions remained relatively stable across CTT subgroups. All ≥ 10-mm lesions were identified in CTT > 90 min and were detected by PCE.

CONCLUSION

In patients with suspected MLGIB, PCE demonstrates good overall diagnostic performance, with excellent accuracy for clinically significant polyps. CTT is a critical determinant of diagnostic reliability, particularly for polypoid lesions. Rapid colonic transit (< 90 min) warrants cautious interpretation of negative PCE examinations.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04782986.