Published online Mar 14, 2019. doi: 10.3748/wjg.v25.i10.1248
Peer-review started: January 2, 2019
First decision: January 18, 2019
Revised: February 14, 2019
Accepted: February 15, 2019
Article in press: February 16, 2019
Published online: March 14, 2019
Processing time: 74 Days and 12.2 Hours
Linked color imaging (LCI) is a method of endoscopic imaging that emphasizes slight differences in red mucosal color.
To evaluate LCI in diagnostic endoscopy of early gastric cancer and to compare LCI and pathological findings.
Endoscopic images were obtained for 39 patients (43 lesions) with early gastric cancer. Three endoscopists evaluated lesion recognition with white light imaging (WLI) and LCI. Color values in Commission Internationale de l'Eclairage (CIE) 1976 L*a*b* color space were used to calculate the color difference (ΔE) between cancer lesions and non-cancer areas. After endoscopic submucosal dissection, blood vessel density in the surface layer of the gastric epithelium was evaluated pathologically. The identical region of interest was selected for analyses of endoscopic images (WLI and LCI) and pathological analyses.
LCI was superior for lesion recognition (P < 0.0001), and ΔE between cancer and non-cancer areas was significantly greater with LCI than WLI (29.4 vs 18.6, P < 0.0001). Blood vessel density was significantly higher in cancer lesions (5.96% vs 4.15%, P = 0.0004). An a* cut-off of ≥ 24 in CIE 1976 L*a*b* color space identified a cancer lesion using LCI with sensitivity of 76.7%, specificity of 93.0%, and accuracy of 84.9%.
LCI is more effective for recognition of early gastric cancer compared to WLI as a result of improved visualization of changes in redness. Surface blood vessel density was significantly higher in cancer lesions, and this result is consistent with LCI image analysis.
Core tip: This study showed the utility of linked color imaging (LCI) for screening endoscopy of early gastric cancer and the concordant change in blood vessel density with redness in LCI image. The key results of the study were as follows: LCI gave better contrast than white light imaging for the color difference between cancer lesions and surrounding non-cancer tissue; an a* cutoff ≥ 24 for the value in Commission Internationale de l'Eclairage 1976 L*a*b* color space had good sensitivity and specificity for diagnosis of early gastric cancer; and surface blood vessel density in cancer lesions was significantly higher than that in non-cancer areas.
