Evaluation of the impact of linked color imaging for improving the visibility of colonic polyp

Red Dichromatic Imaging Improves the Recognition of Bleeding Points During Endoscopic Submucosal Dissection

BACKGROUND

Previous studies have indicated that red dichromatic imaging (RDI) improved the visibility of gastrointestinal bleeding.

AIMS

To investigate the recognition of bleeding points during endoscopic submucosal dissection (ESD) under RDI compared with that under white light imaging (WLI).

METHODS

Consecutive patients scheduled to undergo esophageal or gastric ESD at a single center were enrolled. Paired videos of active bleeding during ESD under WLI and RDI were created. Six endoscopists identified the virtual hemostasis point on still images after random video viewing. The distance between virtual hemostasis and actual bleeding points was scored in four levels (0-3 points), and the association with the color value was analyzed in both WLI and RDI.

RESULTS

We evaluated 116 videos for 58 bleeding points. The median visibility score and recognition rate were significantly higher for RDI than for WLI (2.17 vs. 1.42, p < 0.001 and 62.1% vs 27.6%, p < 0.001). Additionally, the recognition rate of trainees in RDI was higher than that of experts in WLI (60.3% vs. 43.1%, p = 0.067). The median color difference of RDI was significantly higher than that of WLI (8.97 vs. 3.69, p < 0.001). Furthermore, the correlation coefficient between the visibility score and color difference was 0.712 (strong correlation).

CONCLUSION

RDI can provide better recognition of bleeding points than WLI during ESD. Therefore, further studies are warranted to investigate whether RDI improves ESD outcomes.

The Differential Diagnosis of Colorectal Polyps Using Colon Capsule Endoscopy

Objective Although colorectal polyps (CPs) can be observed with colon capsule endoscopy (CCE), it is difficult to determine the type of polyp using CCE. The objective of this study was to differentiate adenomatous polyps (APs) from hyperplastic polyps (HPs) with CCE. Methods In this single-center retrospective study, an analysis was conducted on the same CPs with both CCE and colonoscopy (CS) and histopathologically diagnosed as AP or HP. The color difference (ΔE) between the polyp surface and the surrounding mucosa was calculated using the CIE1976 L*a*b* color space method on white light (WL), flexible spectral imaging color enhancement (FICE), and blue mode (BM) CP images. We investigated the ability of the ratio of the color differences (ΔE') to differentiate between APs and HPs. Results The size of all 51 polyps (34 APs, 17 HPs) was 7.5±4.6 mm with CCE and 7.3±4.2 mm with CS, and this difference was not significant (p=0.28). The FICEΔE' of APs was 3.3±1.8, which was significantly higher than the FICEΔE' of HPs (1.3±0.6; p<0.001). A receiver operating characteristic analysis showed that FICEΔE' was useful for differentiating between APs and HPs, with an area under the curve of 0.928 (95% confidence interval, 0.843-1). The sensitivity was 91.2%, and the specificity was 88.2% with a cut-off value of 1.758. Conclusion Using FICE on CCE images of CPs and applying the CIELAB color space method, we were able to differentiate between APs and HPs with high accuracy. This method has the potential to reduce unnecessary CS procedures.