The Charleston MRCP experience: a tiny step in the right direction

Endoscopic retrograde cholangiopancreatography, intraductal ultrasonography, and magnetic resonance cholangiopancreatography in bile duct strictures: a prospective comparison of imaging diagnostics with histopathological correlation

OBJECTIVES

A variety of imaging techniques are available to diagnose bile duct strictures; the most effective imaging technique, however, has not been established yet. In the present study, we compared the impact of endoscopic retrograde cholangiopancreatography (ERCP), intraductal ultrasonography (IDUS), and magnetic resonance cholangiopancreatography (MRCP) with regard to diagnosing bile duct strictures.

METHODS

We prospectively examined 33 patients with jaundice due to bile duct strictures by ERCP plus IDUS and MRCP. The objectives were to assess diagnostic quality of imaging, complete presentation of the bile duct, and differentiation of malignant from benign lesions. Surgical and histopathological correlations, which were used as the gold standard, were available in all cases since all included patients underwent laparotomy.

RESULTS

Diagnostic image quality for ERCP was 88% and 76% for MRCP (p > 0.05). Comparing ERCP and MRCP, complete presentation of the biliary tract was achieved in 94% and 82%, respectively (p > 0.05). ERCP and MRCP allowed correct differentiation of malignant from benign lesions in 76% and 58% (p= 0.057), respectively. By supplementing ERCP with IDUS, the accuracy of correct differentiation of malignant from benign lesions increased significantly to 88% (p= 0.0047).

CONCLUSIONS

Comparing ERCP with MRCP, we found adequate presentation of bile duct strictures in high imaging quality for both techniques. ERCP supplemented by IDUS gives more reliable and precise information about differentiation of malignant and benign lesions than MRCP alone without additional imaging sequences.

Mathematical model for predicting biliary therapeutic endoscopic retrograde pancreatography (ERCP)

INTRODUCTION

Magnetic resonance cholangiopancreatography is as sensitive as endoscopic retrograde pancreatography in the evaluation of biliary tract diseases but does not offer therapeutic options. The aim of the present study was to develop a mathematical model to predict 'therapeutic endoscopic retrograde pancreatography' using clinical variables so that patients with low probability could be more appropriately investigated by magnetic resonance cholangiopancreatography in future.

METHODS

Endoscopic retrograde pancreatography cases between January 1996 to December 1997 were retrospectively reviewed (before introduction of magnetic resonance cholangiopancreatography). Clinical, biochemical and radiological variables were analysed and a model was developed using multiple logistic regression.

RESULTS

Case notes for 573 patients were successfully reviewed. A total of 330 patients underwent therapeutic endoscopic retrograde pancreatography (sphincterotomy or stent insertion). Clinical indications of obstructive jaundice and cholangitis, ultrasonographic findings of dilated common bile duct, and raised liver function tests (two or more elevated parameters) were each found to be predictive for 'therapeutic' endoscopic retrograde pancreatography. Using these variables, the mathematical model in the present study has specificity of 77% and sensitivity of 75% at the probability level of 50% or higher. This model has been tested in a separate group of endoscopic retrograde pancreatography cases carried out in 1998 and was found to have sensitivity 77.6%, specificity 80.3%, positive predictive value 68.5% and negative predictive value 86.6%.

CONCLUSIONS

The model reported in the present study can help clinicians to identify cases for therapeutic endoscopic retrograde pancreatography and diagnostic magnetic resonance cholangiopancreatography.