Endocytoscopy in real-time assessment of histological and endoscopic activity in ulcerative colitis.

Background: Endocytoscopy is an advanced imaging modality that provides real-time, ultra-high magnification views of the intestinal mucosa. In ulcerative colitis (UC), the combined assessment of endoscopic and histological remission is now becoming a standard practice. However, histological evaluation typically falls outside the scope of the endoscopist. By offering in vivo microscopic imaging, endocytoscopy has the potential to streamline workflow and enhance efficiency in assessing UC activity.

Aim: To evaluate the utility of real-time endocytoscopy in assessing endoscopic and histological disease activity in UC, and to validate endocytoscopic scoring systems.

Methods: This study was conducted at Concord Hospital. Patients with UC who consented to undergo colonoscopy with endocytoscopy were enrolled. Data collected included patient demographics, clinical disease activity, Mayo endoscopic score (MES), and endocytoscopic features such as crypt architecture, intercrypt distance and cellular infiltration. Correlation between endocytoscopic findings were evaluated against MES and the Nancy histological index. Agreement and validation were assessed using the ErLangen Endocytoscopy in ColiTis (ELECT) score and the endocytoscopy score (ECSS), applying Kappa (κ) statistics and Spearman's correlation coefficient (r).

Results: A total of 61 colonic segments from 15 patients were assessed, with 187 analyzable endocytoscopic images. Endocytoscopy showed significant correlation with the MES using both the ECSS (κ = 0.60, P < 0.001; r = 0.78, P < 0.001) and ELECT (κ = 0.88, P < 0.001; r = 0.81, P < 0.001) scoring systems. Similarly, correlations with the Nancy histological index were significant for both ECSS (κ = 0.47, P < 0.001; r = 0.69, P < 0.001) and ELECT (κ = 0.88, P < 0.001; r = 0.74, P < 0.001). The ELECT score demonstrated superior diagnostic accuracy in identifying histological remission, with a sensitivity of 100%, specificity of 85%, and an area under the receiver operating characteristic curve of 0.90 (95% confidence interval: 0.78-1.00), compared to 68.3%, 85%, and an area under the receiver operating characteristic curve of 0.88 (95% confidence interval: 0.75-1.00) for the ECSS. No serious adverse events occurred, except for transient urinary discoloration due to methylene blue excretion.

Conclusion: Endocytoscopy allows for real-time, simultaneous assessment of endoscopic and histological activity in UC and has been proven to be accurate, safe, and well-tolerated. Compared with the ECSS, the ELECT score showed superior concordance with histological findings.