Ex vivo pilot study using computed analysis of endo-cytoscopic images to differentiate normal and malignant squamous cell epithelia in the oesophagus

Background and study aims: An endo-cytoscopy system allows acquisition of optical biopsies that are quite similar to conventional histology. To simplify discrimination between normal and malignant tissue in the oesophagus using endo-cytoscopy system, we analysed the nuclear (dark staining) area in the obtained images with the goal of an accurate, automatic diagnosis. Patients and methods: Ex vivo endo-cytoscopic observation was performed using endoscopically or surgically resected oesophagus from 10 enrolled patients. Oesophageal tissues were stained using 1% methylene blue, and endo-cytoscopic images were obtained at normal and malignant areas (two areas of each) in each oesophagus. The centre of each image (4 × 10^-2 mm²) was processed by computer, and the area occupied by the total nuclei in each selected field and its ratio to the entire field were calculated. Results: The mean area of the total nuclei was 0.10 × 10^-2 ± 0.03 × 10^-2 mm² (range 0.05 × 10^-2 to 0.18 × 10^-2 mm²) in the normal group and 0.40 × 10^-2 ± 0.06 × 10^-2 mm² (range 0.33 × 10^-2 to 0.55 × 10^-2 mm²) in the malignant group (P < 0.001). The mean ratio of total nuclei to the entire selected field was 6.4 ± 1.9% (range 3.1-11.3%) in the normal tissues and 25.3 ± 3.8% (range 20.5-34.5%) in the malignant samples (P < 0.001). Conclusions: Endo-cytoscopy system allowed automatic differentiation of normal and malignant tissues in the oesophagus, which could simplify endo-cytoscopic diagnosis. Further study will elucidate whether such analysis is applicable to inflammatory or pre-malignant epithelia in the oesophagus or other gastrointestinal organs.