S287 Endoscopic Ultrasound vs Magnetic Resonance Cholangiopancreatography in the Etiologic Evaluation of Idiopathic Acute Pancreatitis: A Systematic Review and Meta Analysis

Introduction: Idiopathic acute pancreatitis (IAP) accounts for up to 20% of cases despite comprehensive initial evaluation. Determining the etiology is crucial to guide management and prevent progression to chronic pancreatitis (CP). Endoscopic ultrasound (EUS) and magnetic resonance cholangiopancreatography (MRCP) are second-line imaging modalities, although their relative diagnostic performance remains unclear. This systematic review and meta-analysis compares the diagnostic yield of EUS and MRCP in identifying underlying causes of IAP. Methods: A systematic search of PubMed, EMBASE, and Google Scholar (January 2000–April 2025) identified English-language studies comparing EUS and MRCP diagnostic performance in IAP. Two reviewers independently extracted data and assessed study quality using the Newcastle-Ottawa Scale. Pooled relative risks (RR) were calculated using a random-effects model, with subgroup, sensitivity, and publication bias analyses done per PRISMA 2020. Subgroup analyses assessed diagnostic yield by etiology—biliary disease (cholelithiasis, choledocholithiasis, microlithiasis, and sludge), pancreatic divisum, and malignancy (pancreatic adenocarcinoma and periampullary cancer). Results: Of 4,933 studies screened, 8 met inclusion criteria. Pooled analysis showed EUS had significantly higher diagnostic yield than MRCP (RR = 2.01; 95% CI: 1.42–2.85; P < 0.01; I² = 69.1%). EUS was markedly superior for biliary etiologies (RR = 3.67; 95% CI: 2.08–6.47; P < 0.0001; I² = 37.7%) and trended toward better detection of CP in IAP (RR = 2.20; 95% CI: 0.87–5.55; P = 0.0955; I² = 15.5%). MRCP favored detection of pancreatic divisum (RR = 0.59; 95% CI: 0.31–1.12; P = 0.1078; I² = 0.0%). EUS also demonstrated higher cancer detection compared to MRCP (RR = 1.98; 95% CI: 0.56–7.03; P = 0.2896; I² = 0.0%). Conclusion: EUS surpasses MRCP in diagnosing IAP biliary etiologies and had an overall higher diagnostic yield. Prior studies suggest that EUS may be oversensitive in diagnosing CP, which may be consistent with the increased rate of diagnosis by EUS in our data. There was some signal that EUS had a higher diagnostic yield for cancer which may highlight a potential role in identifying occult malignancy in IAP evaluation. In practice, choosing EUS vs MRCP depends on resource availability, but a patient-centered approach that integrates modality strengths with clinical profiles can improve diagnostic accuracy and prognostic outcomes.