Predictive value of ultrasonography and magnetic resonance cholangiopancreatography in the diagnosis of biliary obstruction.

OBJECTIVE Use of diagnostic tools with high predictive value for common biliary duct (CBD) obstruction has the potential to provide valuable information. This study aimed to examine the respective diagnostic values of biochemistry, abdominal ultrasonography (US), and magnetic resonance cholangiopancreatography (MRCP) in patients with suspected biliary obstruction. MATERIALS AND METHODS A total of 119 patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) based on a suspicion of CBD obstruction were included. Patients also had data for biochemical and hematologic tests, abdominal US and MRCP. The respective sensitivity, specificity, negative predictive value, and positive predictive value of US, MRCP, and the laboratory parameters in the diagnosis of ERCP-confirmed CBD obstruction were estimated. RESULTS ERCP did not show obstruction in 15.1% of the cases. Based on 95% confidence intervals, MRCP had greater sensitivity than ultrasound in predicting obstruction (95% vs. 62%). In addition, ultrasound had a very high 31.9% false negative rate when compared to MR (4.2%). On the other hand, a combined approach had better diagnostic value. None of the laboratory parameters exhibited a predictive value. However, old age was significantly associated with biliary obstruction. CONCLUSION MRCP, particularly when combined with ultrasound, is a useful diagnostic tool for the diagnosis of common biliary duct obstruction and may have the potential to eliminate the need for further ERCP in some patients. On the other hand, US alone does not seem to have acceptable diagnostic value. Further large and prospective studies are warranted to draw firm conclusions. KEY WORDS Biliary Obstruction, Endoscopic Retrograde Cholangiopancreatography (ERCP), Magnetic Resonance Cholangiopancreatography (MRCP), Ultrasonography.