Objectives: To evaluate the value of magnetic resonance cholangiography (MRC) as a systematic first-line investigation in the management of patients with suspected common bile duct stones.
Methods: Ninety-nine consecutive patients with clinical suspicion of choledocolithiasis were prospectively explored by MRC. All MRCs were interpreted by two radiologists with knowledge of the patient's clinical condition and laboratory results. In case of discrepancy, a third opinion was obtained to reach consensus. The definitive diagnosis was established on the basis of endoscopic exploration of the common bile duct (n=40), clinical and biological follow-up at 6 Months (n=55) or other investigations (n=4). The clinician's level of confidence, management options implemented, and impact of management decisions were used to assess the contribution of MRC. The diagnostic accuracy of MRC for common bile duct stones was also determined.
Results: At the observed level of confidence (85.9%), MRC identified a differential diagnosis in 7.1% of patients avoiding unnecessary endoscopic exploration in 59.6%. Systematic first-line MRC enabled appropriate management in 83.8% of patients. The sensitivity, specificity, and positive and negative predictive values of MRC for the diagnosis of common bile duct stones were 95.7%, 98.7%, 95.7% and 98.7%, respectively, with excellent inter-observer agreement (kappa=0.915).
Conclusion: Magnetic resonance cholangiography can be used to efficiently screen patients who may need further invasive exploration of the common bile duct. It specifically identifies patients requiring therapeutic ERCP.