Is there a difference in diagnostic accuracy and clinical impact between endoscopic ultrasonography and magnetic resonance cholangiopancreatography?

Background and Study Aims: It is still unknown whether there is a difference in diagnostic accuracy and clinical impact between endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP). Patients and Methods: The test performance and potential clinical impact of EUS and MRCP, had each investigation been performed as the first examination method, were compared prospectively in 163 patients admitted for and examined by endoscopic retrograde cholangiopancreatography (ERCP). Results: The accuracies of EUS and MRCP were 0.93 and 0.91, respectively (no significant difference, P>0.05). Had EUS or MRCP been performed as the first investigation in the 75 patients who had a presumed high probability for needing therapeutic ERCP, only 15 and nine patients, respectively, would have avoided ERCP. In this group of patients, one patient needed other diagnostic investigations following EUS compared with I I patients following MRCP (P=0.004). For the 57 patients with an intermediate probability of needing endoscopic therapy, EUS and MRCP would have spared 37 and 38 patients, respectively, from the need to have an ERCP. In 31 patients with a presumed low risk of needing endoscopic therapy, 30 and 29 patients would have been spared from ERCP had EUS and MRCP, respectively, been performed initially. Conclusions: There was no difference in the diagnostic accuracy and clinical impact between EUS and MRCP in the majority of the patients. The impact of EUS or MRCP on the ERCP workload was highly dependent on the presumed probability of needing endoscopic therapy.