RESUMEN
<p><b>OBJECTIVE</b>To compare the diagnostic value study the technique of ultrasonography, magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) in common duct stones.</p><p><b>METHODS</b>Three hundreds and eighty-four patients suspected common duct stones from August 2005 to October 2007 were undergone abdominal ultrasonography, MRCP and ERCP.</p><p><b>RESULTS</b>There was stone in common duct in 370 and no stones in 14 of 384 patients. Ultrasonography indicated stones 268 cases, 8 false positive result was among them. MRCP diagnosed stones in 362 cases and false positive result in 6 cases, ERCP diagnosed stones 370 cases. The diagnostic accuracy of ultrasonography, MRCP and ERCP was 70.3% (260/370), 96.2% (356/370) and 100% respectively.</p><p><b>CONCLUSIONS</b>The diagnostic accuracy of ultrasonography for common duct stone was little higher, US should be used as a primary checking method. There was higher concordance between MRCP and ERCP for common duct stone. Combination of MRCP and ERCP can improve diagnostic accuracy of common duct stone.</p>