EVALUATION OF CLINICAL VARIABLES, RADIOLOGICAL VISUAL ANALOG SCORING, AND RADIOMICS FEATURES ON CT ENTEROGRAPHY FOR CHARACTERIZING SEVERE INFLAMMATION AND FIBROSIS IN STRICTURING CROHN’S DISEASE

Abstract

Abstract PURPOSE 25% of patients with Crohn’s disease (CD) develop severe stricturing disease which is non-responsive to standard-of-care medication. Early and non-invasive determination of the extent of inflammation and fibrosis within the stricture via CT enterography (CTE) could facilitate the selection of targeted therapy or earlier surgical resection to improve patient outcomes; but currently there is no validated and reliable approach for this differentiation. We present initial results for machine-reader evaluation of severe inflammation and fibrosis in CD strictures via quantitative radiomic features and expert radiologist scoring on CTE. METHODS AND MATERIALS IRB approved, retrospective, single center study. 100 patients (n=66 for discovery; n=34 for hold-out validation) confirmed with stricturing CD on histopathology and CTE within 15 weeks of surgery. Histopathological Stenosis Therapy & Research (STAR) scoring of specimens (range 0-100, scores > 50 =severe) used as reference standard for inflammation and fibrosis each. An expert radiologist annotated the resected strictures on CTE and provided a global assessment of inflammation and chronic non-inflammatory findings (fibrosis) using a 0-100 visual analog score (VAS). Radiomics features to capture severe inflammation and fibrosis were separately extracted from the annotated strictures. Radiomics models and VAS scores evaluated against pathology-defined severe inflammation and fibrosis, via ROC analysis. RESULTS Two distinct sets of radiomic features capturing textural heterogeneity (patterns, wavelets, local entropy) within strictures were significantly associated (p<0.01) with severe inflammation and severe fibrosis; across both discovery (AUC=0.69, 0.69) and hold-out validation (AUCs =0.72,0.67). Radiological VAS had an AUC=0.64 for identifying severe inflammation and AUC =0.62 for identifying severe fibrosis (Figure 1). Clinical variables including sex, age, Montreal classification and stricture type were not significantly associated with severe inflammation or fibrosis, across discovery and validation groups (Table 1). CONCLUSIONS Radiomic analysis shows improved performance in identifying severe inflammation and severe fibrosis in CD strictures on CTE compared to radiological visual assessment scoring. Supplementing radiological visual assessment with quantitative radiomics could enable more accurate phenotyping of CD strictures potentially improving outcomes by personalizing treatment pathways.