Efficacy of Magnifying Texture and Color Enhancement Imaging With Indigo Carmine as an Alternative to Crystal Violet for Colorectal Tumors

Background: Pit pattern diagnosis using crystal violet staining for colorectal tumors is useful for qualitative and depth diagnosis. However, due to its reported carcinogenic potential, the use of crystal violet has been restricted. This study was aimed at investigating the efficacy of texture and color enhancement imaging (TXI) magnification in pit pattern diagnosis.

Methods: This study enrolled consecutive patients with consent obtained and with colonic tumors indicated for magnifying endoscopy in which all modalities' images (magnified observation with crystal violet staining (CV), magnified white light observation with indigo carmine (IC-WLI), and magnified TXI observation with indigo carmine (IC-TXI)) were evaluable between July 2020 and January 2023. The visibility of the pit pattern using a 5-point Likert scale and its diagnostic accuracy were compared (IC-TXI vs. IC-WLI, reference: CV, by three experts).

Results: A total of 145 colorectal tumors from 145 patients were included. Visibility scores for the pit pattern were significantly higher with IC-TXI compared to IC-WLI (all three experts, p < 0.0001). The pit pattern match rate (Type II/III/IV/V) of IC-TXI compared to CV was also superior to IC-WLI (72.9% vs. 59.7%; p = 0.02).

Conclusions: IC-TXI provided reasonably good and higher visibility and diagnostic accuracy than IC-WLI for pit pattern diagnosis of colorectal tumors compared to CV, suggesting it as an alternative to CV.