LAUSR

BACKGROUND AND AIMS Idiopathic acute pancreatitis (IAP) poses a diagnostic challenge for gastroenterologists, because confirmation of the disease etiology has important implications for the selection of the best possible treatment and the prevention of possible recurrence or the development of chronic pancreatitis (CP). ERCP, EUS, and MRCP typically are used to diagnose IAP when conventional radiologic methods fail. However, their exact role in the diagnosis of IAP has not yet been determined. METHODS We searched the PubMed, EMBASE, OVID, Cochrane Library (including CENTRAL), China National Knowledge Infrastructure (CNKI), and Wanfang databases from inception to April 2017. Studies involving the use of EUS and/or MRCP for the etiologic diagnosis of IAP were included. A meta-analysis was performed by using Review Manager Version 5.2 for comparative studies and R software 3.3.3 to determine diagnostic yield of the studies. RESULTS Among the 34 studies that met the inclusion criteria (n = 2338), 7 studies used a combination of EUS and MRCP and totaled 249 patients. The results comparing EUS with MRCP showed a diagnostic yield of 153 of the 239 patients (64%) in the EUS group, which was higher than the yield of 82 of 238 patients (34%) in the MRCP group (P < .001) in the 7 studies, and the diagnostic yield was 60% in the EUS group, 24% in the MRCP group, and 43% in the MRCP after secretin stimulation (S-MRCP) group. In our subgroup analysis of CP and biliary disease, EUS was superior to MRCP (P < .001), but when comparing the efficacy of the modalities in the diagnosis of pancreatic divisum, S-MRCP was obviously superior to MRCP and EUS (12% vs 2% vs 2%). CONCLUSION EUS and MRCP should both be used in the diagnostic work-up of IAP as complementary techniques. EUS had a higher diagnostic accuracy than MRCP (64% vs 34%) in the etiologic diagnosis of IAP and should be preferred for establishing a possible biliary disease and CP diagnosis, whereas S-MRCP was superior to EUS and MRCP in diagnosing a possible anatomic alteration in the biliopancreatic duct system, such as pancreatic divisum.