Correlation between endoscopic disease activity and cross-sectional imaging scores at diagnosis in pediatric Crohn's disease.

OBJECTIVES: This study aimed to evaluate correlations between transmural inflammation assessed by cross-sectional imaging and endoscopic activity in pediatric Crohn's disease (CD) at diagnosis. METHODS: We retrospectively reviewed data of patients with CD referred to our Pediatric Gastroenterology Unit who underwent ileocolonoscopy, intestinal ultrasound scan, and magnetic resonance enterography (MRE) at diagnosis. The Simplified Endoscopic Score for Crohn's disease (SES-CD) was routinely reported, as per protocol at our institution. Two independent reviewers, blinded to the endoscopic findings, retrospectively calculated the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) and the Pediatric Inflammatory Crohn's Magnetic Resonance Enterography Index (PICMI). Correlations were evaluated using Spearman's rho (ρ). RESULTS: Sixty-seven patients were identified (61.2% males, median age at diagnosis 12.9 years [interquartile range, IQR 10.5-14.9]). Forty-four (65.6%) had ileocolonic disease. While IBUS-SAS showed a positive correlation with PICMI (ρ = 0.377, p = 0.002), SES-CD did not correlate with either PICMI (ρ = 0.101, p = 0.420) or with IBUS-SAS (ρ = 0.003, p = 0.982). SES-CD showed a positive correlation with IBUS-SAS (ρ = 0.810, p < 0.001) and PICMI (ρ = 0.402, p = 0.001) only when calculated for the terminal ileum (TI). MRE failed to identify superficial colonic lesions in 26/47 patients (55.3%) with L2 or L3 disease phenotype. The median SES-CD was significantly higher in patients with detectable colonic disease by MRE compared with those without detectable colonic disease (20 vs. 16; p = 0.042). CONCLUSIONS: In our cohort, the correlation between endoscopic and cross-sectional imaging scores differed according to disease location, with significant associations observed for TI involvement but not for colonic disease.