Use of magnetic resonance cholangiography in the diagnosis ofcholedocholithiasis: prospective comparison with a reference imagingmethod

Background—Magneticresonance cholangiography (MRC) is a new technique for non-invasiveimaging of the biliary tract.
Aim—To assess theresults of MRC in patients with suspected bile duct stones as comparedwith those obtained with reference imaging methods.
Patients/Methods—70patients (34 men and 36 women, mean (SD) age 71 (15.5) years; median75) with suspected bile duct stones were included (cholangitis, 33;pancreatitis, three; suspected post-cholecystectomycholedocholithiasis, nine; cholestasis, six; stones suspected onultrasound or computed tomography scan, 19). MR cholangiograms with twodimensional turbo spin echo sequences were acquired. Endoscopicretrograde cholangiography with or without sphincterotomy (n = 63),endosonography (n = 5), or intraoperative cho- langiography (n = 2)were the reference imaging techniques used for the study and wereperformed within 12 hours of MRC. Radiologists were blinded to theresults of endoscopic retrograde cholangiography and previous investigations.
Results—49patients (70%) had bile duct stones on reference imaging (common bileduct, 44, six of which impacted in the papilla; intrahepatic, four;cystic 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 smallerthan 6 mm. MRC diagnostic accuracy for bile duct lithiasis was:sensitivity, 57.1%; specificity, 100%; positive predictive value,100%; negative predictive value, 50%.
Conclusions—Stonessmaller than 6 mm are still often missed by MRC when standard equipmentis used. The general introduction of new technical improvements isneeded before this method can be considered reliable for the diagnosisof bile duct stones.

Keywords:bile duct calculi; endoscopic retrogradecholangiography; magnetic resonance cholangiography