Accuracy of Magnetic Resonance Cholangiopancreatography in the Diagnosis of Pancreas Divisum

Background Patients with pancreas divisum may develop pancreatitis. Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard for diagnosing pancreas divisum. Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive test reported to be highly accurate in diagnosing pancreas divisum. Aim To evaluate the diagnostic accuracy of MRCP in detecting pancreas divisum at our institution. Methods Wereviewed patients who underwent both ERCP and MRCP. Patients who had diagnostic endoscopic pancreatograms (ERP) after MRCP comprise the study population. Secretin was given in 113/146 patients (S-MRCP). The remaining 33/146 patients had MRCP without secretin. In 7/33 patients who underwent MRCP without secretin (21.2%), the studies were non-diagnostic and, therefore, this group was not further analyzed and the study focused on the S-MRCP group only. Results ERP identified pancreas divisum in 19/113 (16.8%) patients. S-MRCP identified 14/19 pancreas divisum and was false-positive in three cases (sensitivity 73.3%, specificity 96.8%, positive predictive value 82.4%, negative predictive value 94.8%). Of the eight patients with inaccurate S-MRCP, 5 (63%) had changes of chronic pancreatitis by ERP. This differs from the frequency of chronic pancreatitis by ERP in 24/105 (23%) patients with accurate MRCP findings. The ERCP findings of chronic pancreatitis were more frequent among incorrect S-MRCP interpretations than among correct interpretations (odds ratio [OR] 5.5 [95% confidence interval (CI) 1.3–25.3]). Summary MRCP without secretin is non-diagnostic for pancreas divisum in a significant proportion of patients. S-MRCP had a satisfactory specificity for detecting pancreas divisum. However, the sensitivity of S-MRCP for the diagnosis of pancreas divisum was modest at 73.3%. This is low compared to previous smaller studies, which reported a sensitivity of MRCP of up to 100%.