Reproducibility of the electronic chromoendoscopy PICaSSO score (Paddington International Virtual ChromoendoScopy ScOre) in ulcerative colitis using multiple endoscopic platforms: a prospective multicenter international study (with video)

Post written by Marietta Iacucci, PhD, from the Institute of Immunology and Immunotherapy, University of Birmingham, and NIHR Birmingham Biomedical Research Centre, University Hospitals NHS Foundation Trust and University of Birmingham, Birmingham, United Kingdom, and IBD Unit, University of Calgary, Calgary, Alberta, Canada, and Rosanna Cannatelli, MD, from the Institute of Immunology and Immunotherapy, University of Birmingham, and Gastroenterology Unit, Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Milan, Italy.


We focused on the correlation and reproducibility of the newly validated endoscopic score Paddington International Virtual ChromoendoScopy ScOre (PICaSSO), initially developed on the iSCAN platform for ulcerative colitis (UC) patients, when applied to other endoscopic platforms such as narrow-band imaging (NBI), linked-color imaging (LCI), and blue-laser imaging (BLI).

Virtual electronic chromoendoscopy (VEC) drove development of PICaSSO, providing detailed information regarding vascular architecture and surface definition, potentially improving the detection of subtle inflammation, correlating with histology scores, and predicting clinically relevant outcomes.


However, because PICaSSO was developed and validated on iSCAN, its applicability to other major VEC platforms such as NBI, LCI, and BLI needed to be evaluated.

We conducted this prospective study in 2 tertiary referral centers for inflammatory bowel disease on 159 UC patients (78 NBI and 81 BLI/LCI). We used 3 endoscopic scores (Mayo Endoscopic Score, Ulcerative Colitis Endoscopic Index of Severity, and PICaSSO) and 2 histological scores (Robarts Histopathology Index [RHI] and Nancy Histologic Index [NHI]). The correlation between PICaSSO and RHI and NHI was strong at 0.83 and 0.79 in the NBI cohort and 0.63 and 0.65 in LCI/BLI.

In the NBI cohort, the accuracy of PICaSSO was 0.808 for histologic remission (HR) measured by RHI and 0.821 by NHI. In the BLI/LCI cohort, the accuracy of LCI PICaSSO and BLI PICaSSO was 0.827 and 0.79 to predict HR with RHI and NHI, respectively.

Moreover, the intraclass correlation coefficient for PICaSSO scored by NBI was highest at 0.869 and 0.759 scored by BLI/LCI, respectively.

We also confirmed the strong correlation between endoscopic assessment with PICaSSO and the histologic grade of activity with other endoscopic VEC platforms. Furthermore, PICaSSO could be consistently and accurately reproduced with the other major endoscopic platforms such as NBI and LCI/BLI and, therefore, can be applied to all VEC platforms available in daily clinical practice.


Graphical Abstract

Read the full article online.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.

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