Comparison of endoscopic ultrasonography and magnetic resonance cholangiopancreatography in the diagnosis of pancreatobiliary diseases:: A prospective study

Objectives: To compare the diagnostic value of endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP) in: (a) patients with a dilated biliary tree unexplained by ultrasonography (US) (group 1), and (b) the diagnosis of choledocholithiasis in patients with nondilated biliary tree (group 2). Methods: Patients were prospectively evaluated with EUS and MRCP. The gold standard used was surgery or EUS-FNA and ERCP, intraoperative cholangiography, or follow-up when EUS and/or MRCP disclosed or precluded malignancy, respectively. Likelihood ratios (LR) and pretest and post-test probabilities for the diagnosis of malignancy and choledocholithiasis were calculated. Results: A total of 159 patients met one of the inclusion criteria but 24 of them were excluded for different reasons. Thus, 135 patients constitute the study population. The most frequent diagnosis was choledocholithiasis (49% in group 1 and 42% in group 2, P = 0.380) and malignancy was more frequent in group 1 (35% vs 7%, respectively, P < 0.001). When EUS and MRCP diagnosed malignancy, its prevalence in our series (35%) increased up to 98% and 96%, respectively, whereas it decreased to 0% and 2.6% when EUS and MRCP precluded this diagnosis. In patients in group 2, when EUS and MRCP made a positive diagnosis of choledocholithiasis, its prevalence (42%) increased up to 78% and 92%, respectively, whereas it decreased to 6% and 9% when any pathologic finding was ruled out. Conclusions: EUS and MRCP are extremely useful in diagnosing or excluding malignancy and choledocholithiasis in patients with dilated and nondilated biliary tree. Therefore, they are critical in the approach to the management of these patients.