Objective Loss of surface maturation and cytonuclear atypia have been regarded as the pathological ‘gold standard’ for the diagnosis of oesophageal squamous cell intraepithelial neoplasia. However, there has been no satisfactory endomicroscopic method similar to this pathological approach to detect surface maturation and screen for oesophageal squamous cell intraepithelial neoplasia. The aim of this study was to apply a 3-dimensional (3D) confocal endomicroscopic imaging technique to investigate the surface maturation of the oesophageal epithelium and develop new 2-dimensional confocal endomicroscopic criteria based on surface maturation.

Design In the 3D reconstruction phase, intrapapillary capillary loops were reconstructed to demonstrate the stereo configuration of the oesophageal epithelium, and a novel surface maturation scoring (SMS) method for plane confocal images was developed based on the interpretation of the 3D microstructure. In the SMS diagnostic phase, 1214 patients were screened and confocal images from 64 non-invasive oesophageal lesions were independently evaluated using SMS and previous methods.

Results We successfully obtained and interpreted 3D confocal images of the human oesophageal epithelium for the first time. The sensitivity (81.0%, 95% CI 58.1% to 94.6%) and specificity (90.7%, 95% CI 77.9% to 97.4%) of the newly established SMS were superior to previous confocal approaches in distinguishing squamous intraepithelial neoplasia from other non-invasive lesions.

Conclusions 3D confocal endomicroscopic imaging provides valuable insight into the stereo configuration of the human oesophageal epithelium. SMS is a novel and promising diagnostic method to distinguish neoplasia during ongoing endoscopy.