Endoscopic Ultrasound and Magnetic Resonance Cholangiopancreatography in Patients with Idiopathic Acute Pancreatitis

The efficacy of endoscopic ultrasonography (EUS) to diagnose idiopathic acute pancreatitis has been demonstrated but that of magnetic-resonance cholangiopancreatography (MRCP) remains unclear. The aim of our study was to prospectively compare the results of EUS and MRCP to diagnose idiopathic acute pancreatitis when performed later after an acute attack. All patients admitted to our center for acute pancreatitis over a 2-year period received first-line investigations that included medical history, standard biological measurements, abdominal ultrasound, and computerized tomography. If no etiology was found, second-line investigations were scheduled at 2 months (or more if there was severe pancreatitis), which included clinical examinations, biological parameters, EUS, and MRCP. A total of 128 consecutive patients were included (male: 80, mean age: 55.3 years). After first-line investigations, 41 patients with idiopathic acute pancreatitis underwent second-line investigations and were followed-up (38 patients had both EUS and MRCP). EUS and/or MRCP led to recognize a possible etiology of pancreatitis in 19 patients (50 %). The diagnostic yield for EUS was higher than for MRCP (29 vs. 10.5 %). EUS more accurately detected biliary stones whereas MRCP identified pancreatic duct abnormalities, such as intraductal papillary mucinous neoplasm of the pancreas or chronic pancreatitis. The combination of EUS and MRCP, when performed later after idiopathic acute pancreatitis, revealed 50 % of etiologies. The association of these two procedures and the subsequent follow-up reduced the rate of idiopathic pancreatitis by similar to 66 %.