Abstract: We included a total of 18 studies involving 2366 participants (976 participants with common bile duct stones and 1390 participants without common bile duct stones). Eleven studies evaluated EUS alone, and five studies evaluated MRCP alone. Two studies evaluated both tests. Most studies included patients who were suspected of having common bile duct stones based on abnormal liver function tests; abnormal transabdominal ultrasound; symptoms such as obstructive jaundice, cholangitis, or pancreatitis; or a combination of the above. The proportion of participants who had undergone cholecystectomy varied across studies. Not one of the studies was of high methodological quality. For EUS, the sensitivities ranged between 0.75 and 1.00 and the specificities ranged between 0.85 and 1.00. The summary sensitivity (95% confidence interval (CI)) and specificity (95% CI) of the 13 studies that evaluated EUS (1537 participants; 686 cases and 851 participants without common bile duct stones) were 0.95 (95% CI 0.91 to 0.97) and 0.97 (95% CI 0.94 to 0.99). For MRCP, the sensitivities ranged between 0.77 and 1.00 and the specificities ranged between 0.73 and 0.99. The summary sensitivity and specificity of the seven studies that evaluated MRCP (996 participants; 361 cases and 635 participants without common bile duct stones) were 0.93 (95% CI 0.87 to 0.96) and 0.96 (95% CI 0.90 to 0.98). There was no evidence of a difference in sensitivity or specificity between EUS and MRCP (P value = 0.5). From the included studies, at the median pre-test probability of common bile duct stones of 41% the post-test probabilities (with 95% CI) associated with positive and negative EUS test results were 0.96 (95% CI 0.92 to 0.98) and 0.03 (95% CI 0.02 to 0.06). At the same pre-test probability, the post-test probabilities associated with positive and negative MRCP test results were 0.94 (95% CI 0.87 to 0.97) and 0.05 (95% CI 0.03 to 0.09). Both EUS and MRCP have high diagnostic accuracy for detection of common bile duct stones. People with positive EUS or MRCP should undergo endoscopic or surgical extraction of common bile duct stones and those with negative EUS or MRCP do not need further invasive tests. However, if the symptoms persist, further investigations will be indicated. The two tests are similar in terms of diagnostic accuracy and the choice of which test to use will be informed by availability and contra-indications to each test. However, it should be noted that the results are based on studies of poor methodological quality and so the results should be interpreted with caution. Further studies that are of high methodological quality are necessary to determine the diagnostic accuracy of EUS and MRCP for the diagnosis of common bile duct stones.

Plain-language summary: We performed a thorough search for studies that reported the accuracy of EUS or MRCP in the diagnosis of CBD stones. We included a total of 18 studies involving 2532 participants. Eleven studies evaluated EUS alone, five studies evaluated MRCP alone, and two studies evaluated both tests. A total of 1537 participants were included in the 13 studies that evaluated EUS and 995 participants were included in the seven studies that evaluated MRCP. Most studies included patients who were suspected of having CBD stones based on abnormal blood tests, abnormal ultrasound, or symptoms such as jaundice or pancreatitis, or a combination of the above. The proportion of participants who had undergone previous gallbladder removal varied across studies. Based on an average sensitivity of 95% for EUS, on average 95 out of 100 people with CBD stones will be detected while the remaining 5 people will be missed and will not receive appropriate treatment. The average number of people with CBD stones detected using EUS may vary between 91 and 97 out of 100 people. The average specificity of 97% for EUS means that on average 97 out of 100 people without CBD stones will be identified as not having CBD stones; 3 out of 100 would be false positives and would not receive appropriate treatment. The average number of false positives could vary between 1 and 6 out of 100 people. For MRCP, an average sensitivity of 93% means that on average 93 out of 100 people with CBD stones will be detected while the remaining 7 people will be missed and will not receive appropriate treatment. The average number of people with CBD stones detected using MRCP may vary between 87 and 96 out of 100 people. With an average specificity of 96% for MRCP, 96 out of 100 people without CBD stones will be identified as not having CBD stones; 4 out of 100 would be false positives and would not receive appropriate treatment. The average number of false positives could vary between 2 and 10 out of 100 people. This means that some people with CBD stones can be missed by EUS and MRCP. Although most people with a negative EUS or MRCP do not need to undergo further invasive tests, in the presence of persistent symptoms further testing with MRCP if the patient had undergone EUS or EUS if the patient had undergone MRCP, ERCP, or IOC may be indicated. There is little to choose between EUS and MRCP in terms of diagnostic accuracy. All the studies were of low methodological quality, which may undermine the validity of our findings. Further studies of high methodological quality are necessary.