Quantitative MRI Markers Detect Post-Pancreatitis Changes and Diabetes: A Prospective Cohort Study

Introduction: Pediatric acute pancreatitis (AP) prevalence is increasing, yet early imaging markers identifying progression to acute recurrent pancreatitis (ARP) and pancreatitis-related endocrine dysfunction (DM/Pre-DM) are unknown. Quantitative MRI measures including T1 relaxation, T1 signal intensity ratio, proton density fat fraction (PDFF), and pancreatic volume may help characterize disease stage but have not been prospectively evaluated after a single AP episode. Methods: This prospective, single-center study enrolled participants aged 5-30 years. Participants were imaged ≥4 weeks after their most recent AP episode and classified as single AP (n=21), ARP (n=23), or DM/Pre-DM (n=16). 3T MRI included MOLLI-based T1 mapping, mDixon Quant PDFF, and pancreatic volumetric assessments. Clinical, laboratory, and genetic data were collected. Group comparisons, correlation analyses, ANOVA, and ROC analyses with repeated 10-fold cross-validation were performed. Results: Sixty participants (median age 15.6 years) completed imaging. ARP showed higher T1 relaxation (1014 vs 819ms, p=0.015) and pancreatic PDFF (3.7% vs 1.7%, p=0.021) than AP. DM/Pre-DM participants had the highest liver PDFF (9.9 vs 3.6% in AP and 2.7% in ARP, p=0.024). Pancreatic volume, adjusted for body surface area, did not differ significantly. Liver PDFF was the strongest single predictor of DM/Pre-DM (AUC 0.77). A combined model including liver PDFF, pancreatic PDFF, and pancreatic volume improved discrimination (AUC 0.82). Conclusions: Quantitative MRI demonstrates distinct imaging features in children and young adults with ARP and pre-DM/DM. Increased T1 relaxation and pancreatic fat characterize ARP, while hepatic fat is most strongly associated with endocrine dysfunction. Multi-marker models improve classification and require validation in larger cohorts.