Ulcerative Colitis Severity Classification and Localised Extent (UC-SCALE): An Artificial Intelligence scoring system for a spatial assessment of disease severity in Ulcerative Colitis.
The fully-automated UC-SCALE algorithm provides a topological representation of the score as a marker of disease severity that correlates highly with clinical metrics and holds promise to enhance disease severity evaluation in both clinical trials and everyday practice.
Abstract
BACKGROUND & AIMS Validated scoring methods such as the Mayo Clinic Endoscopic Subscore (MCES) evaluate ulcerative colitis (UC) severity at the worst colon segment, without considering disease extent. We present the Ulcerative Colitis Severity Classification and Localised Extent (UC-SCALE) algorithm, which provides a comprehensive and automated evaluation of endoscopic severity and disease extent in UC. METHODS UC-SCALE consists of 3 main elements: 1) a quality filter selecting readable images (frames) from colonoscopy videos, 2) a scoring system assigning a MCES to each readable frame, and 3) a camera localisation algorithm assigning each frame to a location within the colon. UC-SCALE was trained and tested using 4326 sigmoidoscopy videos from phase III Etrolizumab clinical trials. RESULTS The high agreement between UC-SCALE and central reading at the level of colon section (𝜅=0.80), and the agreement between central and local reading (𝜅=0.84), suggested a similar inter-rater agreement between UC-SCALE and experienced readers. Furthermore, UC-SCALE correlated with disease activity markers such calprotectin, C-reactive protein and patient reported outcomes, Physician Global Assessment and Geboes Histologic scores (rs 0.40-0.55, ps < 0.0001). Finally, the value of using UC-SCALE was demonstrated by assessing individual endoscopic severity between baseline and induction. CONCLUSIONS Our fully-automated scoring system enables accurate, objective and localised assessment of endoscopic severity in UC patients. Additionally, we provide a topological representation of the score as a marker of disease severity that correlates highly with clinical metrics. UC-SCALE reproduces central reading and holds promise to enhance disease severity evaluation in both clinical trials and everyday practice.