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P148 Reproducibility of PICaSSO score by using narrow banding images (NBI) to assess mucosal and histological healing in ulcerative colitis (UC) patients

R. Cannatelli1,2, O. Nardone1, U. Shivaji1,3, S.C.L. Smith1,3, A. Bazarova4, D. Zardo5, S. Ghosh1,3,6, M. Iacucci1,3,6

1University of Birmingham, Institute of Translational Medicine, Birmingham, UK, 2University of Milan, Gastroenterology, Milan, Italy, 3University of Birmingham, NIHR Biomedical Research Centre, Birmingham, UK, 4University of Cologne, Institute for Biological Physics, Cologne, Germany, 5University Hospitals Birmingham NHS Foundation Trust, Department of Histopathology, Birmingham, UK, 6University of Calgary, IBD Unit, Calgary, Canada

Background

The endoscopic and histological healing are key therapeutic targets in ulcerative colitis(UC) patients. PICaSSO (Paddington International virtual ChromoendoScopy ScOre)1,2 is a new Virtual Chromoendoscopy Endoscopic (VCE) score to better define mucosal healing by mucosal and vascular features. Originally validated using iSCAN platform, the aim of this study was to evaluate the reproducibility of PICaSSO with NBI near focus platform and to assess if this could predict histological healing.

Methods

We prospectively studied 78 UC patients (mean age 43.4 years, 52.6% male) who underwent colonoscopy for colitis assessment or surveillance using NBI near focus (Olympus, Japan). Endoscopic activity was assessed by using ulcerative colitis Endoscopic Index of Severity (UCEIS) and PICaSSO; whilst histological activity was scored by the Robarts Histology Index (RHI). ROC curves were performed to evaluate sensitivity, specificity and accuracy of endoscopy scores to predict histological healing.

Results

Out of 78 patients, 47 (60.3%) were in clinical remission according to the partial Mayo score. 28(35.9%) and 32(41.0%) were in endoscopic remission according to UCEIS≤1 and PICaSSO≤3, respectively. The best cut-off of UCEIS to predict histological healing was less or equal to 1. Sensitivity, specificity and accuracy were 84.6% (95% CI 63.5, 96.4), 88.5% (95% CI 70.1, 97.8) and 87.2% (95% CI 75.6, 93.6), respectively. The Area Under the ROC curve (AUROC) was 93.3% (95% CI 88.2, 98.3). The best threshold of PICaSSO in the prediction of histological healing was less or equal to 3. PICaSSO ≤ 3 have sensitivity of 96.2% (95% CI 76.9, 100), specificity of 86.5% (95% CI 67.3, 96.2) and accuracy of 89.7% (95% CI 77.6, 96.2) to predict histological healing, estimated as RHI ≤ 3. The AUROC was 95.3% (95% CI 91.1, 99.5).

Conclusion

PICaSSO VCE score can be easily and accurately reproduced with NBI near focus platform and it has better operating characteristics than UCEIS to predict histological healing defined by RHI.

Reference:

Iacucci M, Daperno M, Lazarev M, et al. Development and reliability of the new endoscopic virtual chromoendoscopy score: the PICaSSO (Paddington International Virtual ChromoendoScopy ScOre) in ulcerative colitis. Gastrointest Endosc 2017; 86(6): 1118–27.e5.

Trivedi PJ, Kiesslich R, Hodson J, et al. The Paddington International Virtual Chromoendoscopy Score in ulcerative colitis exhibits very good inter-rater agreement after computerized module training: a multicenter study across academic and community practice (with video). Gastrointest Endosc 2018; 88(1): 95–106.e2.