LINKED COLOR IMAGING OF GASTRIC INTESTINAL METAPLASIA IS IMPORTANT TO IDENTIFY EARLY GASTRIC CANCER WITH HIGH COLOR CONTRAST

Aims:

It is difficult to precisely identify gastric cancer and surrounding intestinal metaplasia by conventional white light imaging (WLI) despite the pathological relationship between them. Purple color mucosa by linked color imaging (LCI) is reported to have potential to correspond to intestinal metaplasia near early gastric cancer. The aim is to clarify characteristic features of LCI regarding early gastric cancers and background intestinal metaplasia.

Methods:

Fifty-two patients with early gastric cancer were enrolled in this prospective study. Based on biopsy specimens of purple color and non-purple color mucosae near early gastric cancer, the detection rate of intestinal metaplasia by LCI was calculated. Also, color differences were determined between malignant lesions and the adjacent mucosa using WLI and LCI before resection and compared with the histological findings of resected specimens.

Results:

Using LCI, forty of 48 lesions with purple mucosa and 8 of 48 lesions with non-purple mucosa near cancers were diagnosed as intestinal metaplasia by biopsy, accounting for 83.4% of specificity, 83.4% of sensitivity and 83.4% of accuracy. Most lesions of 57 cancers have a similar color to surrounding mucosa on WLI, while they were easily detected as orange-reddish lesions surrounded by identifiable purple color mucosa on LCI. Greater mean color differences were present in LCI compared with WLI, leading to higher contrast (17.2 vs. 10.1, P < 0.001). Significant differences were seen not only for elevated and depressed type cancers but also for flat type cancers, which are usually extremely difficult to detect by WLI. The surrounding purple mucosa corresponded histologically to intestinal metaplasia in most specimens and was useful to identify malignant lesions.

Conclusions:

LCI exhibits characteristic purple intestinal metaplasia near and close to early gastric cancers and provides better color contrast compared with conventional imaging using screening endoscopy, and may facilitate diagnosis as a new endoscopic approach.