Value of endoscopic ultrasonography combined with magnetic resonance cholangiopancreatography in diagnosis of patients suspected of common bile duct stones

Objective To investigate whether endoscopic ultrasonography (EUS) combined with magnetic resonance cholangiopancreatography (MRCP) can improve the diagnostic efficiency of such combination in the diagnosis of patients suspected of common bile duct stones.Methods A retrospectively analysis was performed for the clinical data of 78 patients who visited Shengjing Hospital of China Medical University from January 2014 to June 2016 and were diagnosed with suspected common bile duct stones.All patients underwent EUS and MRCP during the same period of hospitalization.The patients were divided into EUS group, MRCP group, and combined diagnosis group according to the imaging examination.Laparoscopic common bile duct exploration, laparoscopic common bile duct exploration, endoscopic retrograde cholangiopancreatography/endoscopic sphincterotomy, and no symptom of abdominal pain within 6 months after discharge were used as the gold standard.The results of the three groups were compared with the gold standard to calculate the sensitivity, specificity, accuracy, positive predictive value, negative predictive value, and Youden index of the imaging findings in three groups.The parallel test was used for combined diagnosis;positive results of EUS or MRCP were considered positive, and negative results of EUS and MRCP were considered negative.The chi-square test was used for comparison of the above indices.Results EUS found positive results in 22 patients, among whom20 had true positive results and 2 had false positive results, and negative results in 56 patients, among whom 53 had true negative results and3 had false negative results.MRCP found positive results in 22 patients, among whom 15 had true positive results and 7 had false positive results, and negative results in 56 patients, among whom 48 had true negative results and 8 had false negative results.EUS combined with MRCP found positive results in 29 patients, among whom 22 had true positive results and 7 had false positive results, and negative results in49 patients, among whom 48 had true negative results and 1 had false negative results.The EUS group had a significantly higher diagnostic accuracy than the MRCP group (93.6%vs 80.8%, χ2=5.735, P=0.017) .There were no significant differences between the combined diagnosis group and the EUS group in sensitivity, specificity, accuracy, positive predictive value, and negative predictive value (P>0.05) .The combined diagnosis group had significantly higher sensitivity and negative predictive value than the MRCP group (sensitivity:95.7%vs 65.2%, χ2=6.769, P=0.009;negative predictive value:98.0%vs 85.7%, χ2=5.000, P=0.025) .Conclusion EUS and MRCP have their own advantages and disadvantages in the diagnosis of suspected common bile duct stones and can be used as the preferred choice for disease diagnosis.EUS has a higher overall accuracy than MRCP, and in patients who plan to undergo laparoscopic cholecystectomy due to gallstones, EUS is more reliable and it is recommended to perform EUS to exclude common bile duct stones.Compared with MRCP alone, EUS combined with MRCP can improve sensitivity and negative predictive value;when MRCP yields negative results which are not consistent with other clinical manifestations, EUS should be performed to confirm the presence of suspected common bile duct stones.