MR versus multislice CT cholangiography in evaluating patients with obstruction of the biliary tract

BACKGROUND: We compared magnetic resonance cholangiography (MRC) with multislice computed tomographic (MSCT) cholangiography in the assessment of patients with bile duct obstruction. METHODS: Thirty-six patients with clinical or biochemical signs of biliary obstruction were prospectively studied. MRC was performed with fast spin-echo and single-shot fast spin-echo sequences. Source images, maximum intensity projection, and multiplanar reconstruction were evaluated. MSCT cholangiography was performed without biliary contrast agent, with intravenous injection of 150 mL of iodinated contrast material at 4 mL/s, 2.5-mm slice thickness, 7.5-mm/s table speed, and 1.25-mm reconstruction interval. Axial, multiplanar, and minimum intensity projection reformatted images were evaluated. MRC and MSCT findings were compared with endoscopic retrograde cholangiopancreatography (ERCP; 20 patients), percutaneous cholangiography (eight patients), intraoperative cholangiography (two patients), surgery (11 patients), and cytology (11 patients) with respect to cause and site of obstruction. RESULTS: With regard to presence and site of obstruction, agreement was observed across MRC, MSCT cholangiography, and reference investigations in all cases. Concerning cause, the correct diagnosis was made by MSCT cholangiography in 34 of 36 patients. Two cases of common bile duct lithiasis, diagnosed on MRC and ERCP, were missed by MSCT cholangiography. CONCLUSION: MSCT cholangiography can be considered a possible noninvasive alternative to MRC.