Use of magnetic resonance cholangiography in the diagnosis of choledocholithiasis: prospective comparison with a reference imaging method

Background-Magnetic resonance cholangiography (MRC) is a new technique for non-invasive imaging of the biliary tract. Aim-To assess the results of MRC in patients with suspected bile duct stone s as compared with those obtained with reference imaging methods. Patients/Methods-70 patients (34 men and 36 women, mean (SD) age 71 (15.5) years; median 75) with suspected bile duct stones were included (cholangiti s, 33; pancreatitis, three; suspected post-cholecystectomy choledocholithia sis, nine; cholestasis, six; stones suspected on ultrasound or computed tom ography scan, 19). MR cholangiograms with two dimensional turbo spin echo s equences were acquired. Endoscopic retrograde cholangiography with or witho ut sphincterotomy (n = 63), endosonography (n = 5), or intraoperative chola ngiography (n = 2) were the reference imaging techniques used for the study and were performed within 12 hours of MRC. Radiologists were blinded to th e results of endoscopic retrograde cholangiography and previous investigati ons. Results-49 patients (70%) had bile duct stones on reference imaging (common bile duct, 44, six of which impacted in the papilla; intrahepatic, four; c ystic duct stump, one). Stone size ranged from 1 to 20 mm (mean 6.1, median 5,5). Twenty seven patients (55%) had bile duct stones smaller than 6 mm. MRC diagnostic accuracy for bile duct lithiasis was: sensitivity, 57.1%; sp ecificity, 100%; positive predictive value, 100%; negative predictive value , 50%. Conclusions-Stones smaller than 6 mm are still often missed by MRC when sta ndard equipment is used. The general introduction of new technical improvem ents is needed before this method can be considered reliable for the diagno sis of bile duct stones.