Efficacy of linked colour imaging in magnifying chromoendoscopy with crystal violet staining: a pilot study

Purpose Diagnosis of the depth of invasion is crucial in the endoscopic management of early colorectal cancer. Image-enhanced endoscopy (IEE) is a method for easily evaluating the depth of invasion. Linked colour imaging (LCI) is an IEE method that enables clearer identification of neoplastic lesions and mucosal inflammation. The aim of this experimental study was to explore the efficacy of LCI in vessel and pit pattern recognition when used in magnifying chromoendoscopy with crystal violet staining for superficial colorectal neoplasms. Methods This was an experimental study. Colour difference (CD) values between the surrounding mucosa and vessels and pits were measured on white light (WLI), blue laser (BLI), and LCI images. The CD values of 10 neoplastic lesions were calculated and compared between WLI and the other techniques. Results The CD value was 9.8 (interquartile range, 7.3–12.4) for WLI, 9.7 (6.7–13.4) for LCI, and 6.8 (5.1–9.3) for BLI. The CD value was statistically different between WLI and BLI but not between WLI and LCI. With regard to vessel description, the CD value was 7.5 (4.0–11.0) for WLI, 15.6 (11.6–23.9) for LCI, and 23.3 (15.8–30.4) for BLI. Conclusions LCI provides more diagnostic information than other light modes. Further, it is superior to the other techniques in terms of vessel visibility and is comparable to them in terms of pit recognition. These unique features of LCI may lead to its use as an alternative to WLI and BLI for pit and vessel pattern evaluation in the future.