{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T10:04:47Z","timestamp":1780653887534,"version":"3.54.1"},"reference-count":23,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T00:00:00Z","timestamp":1780617600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Accurate pT1b diagnosis in colorectal cancer is vital owing to the risk of lymph node metastasis. While Japan NBI (narrow band imaging) Expert Team (JNET) classification is widely applied, accurate diagnosis of type 2B lesions remains challenging, often requiring pit pattern analysis via magnifying chromoendoscopy with crystal violet staining (MCE). However, the clinical application of MCE is limited by potential carcinogenicity and prolonged procedure time. In this study, we aimed to evaluate the diagnostic performance of red dichromatic imaging with indigo carmine (RDI-indigo) in assessing the invasion depth of colorectal tumors. Methods: Ninety images were obtained from 30 colorectal tumor cases using RDI-indigo, NBI, and MCE. Six endoscopists classified images using JNET classification for NBI, and pit pattern classification for RDI-indigo and MCE. JNET type 3 and pit pattern classification V irregular, high grade\/V non-structure were correlated with pathological depth \u2265pT1b. The primary outcome was the diagnostic accuracy for \u2265pT1b. Results: Diagnostic accuracies for \u2265pT1b were 85.0% (95% CI: 79.8\u201390.2%) for RDI-indigo, 79.4% (95% CI: 73.5\u201385.3%) for NBI, and 82.8% (95% CI: 77.3\u201388.3%) for MCE. Intraobserver agreement between RDI-indigo and MCE showed fair agreement (Cohen\u2019s kappa = 0.39), while interobserver agreement was moderate for MCE (Fleiss\u2019 kappa = 0.56) and fair for RDI-indigo (Fleiss\u2019 kappa = 0.36). Gwet\u2019s AC1 indicated substantial agreement across all assessments (0.69\u20130.80). Conclusions: As the first report evaluating RDI-indigo for colorectal tumors, this study suggests that RDI-indigo could serve as a complementary MCE-like tool for the diagnosis of \u2265pT1b lesions.<\/jats:p>","DOI":"10.3390\/diagnostics16111739","type":"journal-article","created":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T08:43:04Z","timestamp":1780648984000},"page":"1739","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Assessment of Red Dichromatic Imaging with Indigo Carmine for Identifying Deep Submucosal Invasion in Colorectal Tumors: A Pilot Study"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0473-7395","authenticated-orcid":false,"given":"Toshiki","family":"Futakuchi","sequence":"first","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Naoto","family":"Tamai","sequence":"additional","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mai","family":"Fukuda","sequence":"additional","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuko","family":"Hasegawa","sequence":"additional","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2291-8600","authenticated-orcid":false,"given":"Mamoru","family":"Ito","sequence":"additional","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Naoya","family":"Tada","sequence":"additional","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masakuni","family":"Kobayashi","sequence":"additional","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8392-1870","authenticated-orcid":false,"given":"Machi","family":"Suka","sequence":"additional","affiliation":[{"name":"Department of Public Health and Environmental Medicine, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazuki","family":"Sumiyama","sequence":"additional","affiliation":[{"name":"Department of Endoscopy, The Jikei University School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,5]]},"reference":[{"key":"ref_1","unstructured":"Health Canada (2026, June 02). 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