Development and assessment of morphologic criteria for diagnosing gastric cancer using confocal endomicroscopy: an ex vivo and in vivo study

Background and study aims: The Confocal Endomicroscopy System (Optiscan Pty Ltd. and Pentax Corp.) is a newly developed imaging tool that uses laser light and optical technology to visualize living tissue at the cellular level. Digital images of cells magnified 1000-fold appear in real time on a computer screen, which enables immediate detection of changes in cellular structure without the need for a biopsy. The aim of this study was to assess the features of the cellular architecture of cancerous tissue that can be used in the differential diagnosis of cancerous tissue and normal mucosa using this system’s image-processing software.
Patients and methods: A total of 27 gastric cancers were examined ex vivo using confocal endomicroscopy. A fluorescent contrast agent, acriflavine, was applied topically to normal and to cancerous mucosa. In vivo imaging of the gastric mucosa after intravenous injection of fluorescein sodium was also performed in nine patients with gastritis or gastric cancer.
Results: The nuclear area in the ex vivo specimens was calculated using Scion Image software. The mean nuclear area of cancer cells was found to be significantly larger than that of normal cells in 18/27 gastric cancers (67 %). The mean nuclear area of the cancers tended to be larger than that of normal mucosa, especially in cases of differentiated adenocarcinoma. In more than half the cases, it was possible to diagnose malignancy automatically using confocal endomicroscopy and image-processing software without the need for biopsy and pathological examination. In vivo imaging of cancerous lesions showed irregularity in cellularity and vascularity.
Conclusion: The ability of this imaging device to differentiate between normal tissue and cancerous tissues gives it potential value as a new screening tool for early detection of malignancy.

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