In-vivo Diagnosis of Gastric Intestinal Metaplasia Using Probe-Based Confocal Laser-Induced Endomicroscopy (pCLE)

Abstract

Purpose: Gastric Intestinal Metaplasia (GIM) is a pre-malignant lesion that can lead to the development of intestinal-type gastric cancer. Confocal laser-induced endomicroscopy is a novel technology that allows for in-vivo diagnosis of a variety of gastrointestinal pathology. CLE criteria for the diagnosis of GIM has been proposed for endoscopic confocal laser endomicroscopy (eCLE) but no established criteria exist for GIM diagnosis using probe-based confocal laser endomicroscopy (pCLE). Given the inherent differences between eCLE and pCLE technology, pCLE criteria for the diagnosis of GIM are needed. The aim of this study is to formulate and test pCLE criteria for the diagnosis of Gastric Intestinal Metaplasia. Methods: Part 1: Retrospective Study - Video sequences of pCLE in 20 patients with a histologic diagnosis of GIM were reviewed. Based on this review and the current literature on eCLE diagnosis of GIM, criteria were proposed for consideration as pCLE criteria for GIM. Part 2: Prospective Study - Consecutive patients with a history of GIM or suspected GIM were evaluated with endoscopy and chromoendoscopy with methylene blue (MB). MB positive and MB negative targeted areas of the stomach were imaged using pCLE and in-vivo diagnosis of GIM was made based on the newly devised criteria. Each area imaged with pCLE was biopsied with cold forceps to evaluate for diagnostic accuracy of pCLE. Results: Part 1: A total of 85 video sequences in 20 patients were reviewed retrospectively. Two diagnostic criteria for GIM were devised. Criteria 1) The presence of round dark structures (8-14 um) within the columnar epithelium (Goblet cells). Criteria 2) Thickened glands with villiform architecture with cell height > 40 um. Part 2: Ninety-one gastric sites in 19 patients were evaluated for GIM using pCLE and biopsy. The calculated sensitivity, specificity, PPV, NPV and accuracy for diagnosis of GIM using Criteria 1 and Criteria 2 was 90.9%, 97.2, 98%, 87.5%, 93.4% and 78.2.4%, 100%, 100%, 75%, 86.8% respectively. Calculated values for using the combined criteria (either criteria 1 or 2 present) were 92.7%, 97.2%, 98.1% 89.7% and 94.5%, p-value < 0.001. Conclusion: Probe-based CLE appears to be accurate for the in-vivo diagnosis of gastric intestinal metaplasia. Two pCLE criteria that are highly specific for GIM diagnosis are the presence of round dark structures (8-14 um) within the columnar epithelium which represent goblets cells and thickened glands with villiform architecture with cell height >40 um.Table 1: Gastric Intestinal Metaplasia (GIM) diagnosis by pCLE and histology