Role of Magnetic Resonance Cholangiopancreatography in Evaluation of Biliary Obstruction

Background: obstructive jaundice which is caused by bile duct obstruction can be clinically and biochemically indistinguishable from cholestatic jaundice caused by hepatocellular disease. The management of both these conditions being radically different, the principle task of the radiologist is to differentiate between hepatocellular and obstructive jaundice, by using available imaging modality and help in further management. With the availability of non-invasive modality like magnetic resonance imaging (MRI), it is possible to diagnose obstructive jaundice early and accurately without any patient discomfort. The purpose of this article is to describe the protocol for evaluation of obstructive jaundice with use of magnetic resonance cholangio pancreatography sequence of MRI and to describe the imaging features of the most common causes of obstructive jaundice like biliary calculi, bile duct strictures, choledochal cyst, gall bladder carcinoma, cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic head carcinoma. Aim of work: this work aimed to study and evaluate the role of MRCP in patients with biliary obstruction. Patients and Methods: this study included 30 patients with biliary obstruction during the period from December 2017 to October 2018. MRCP was performed on a 1.5 T MRI system, using a phased-array body coil. Fasting for 4 hours prior to the examination is required to reduce gastro-duodenal secretions, reduce motility to eliminate motion artifacts and to promote distension of gall bladder.For optimum visualization of ducts, acquired images were reformatted in different planes using multiplanar reconstruction (MPR) and maximum intensity projection (MIP). Results: in all cases, MRCP displayed the different parts of the biliary tract and localized the exact site of obstruction in all of the obstructed cases. According to the morphology encountered at the site of obstruction, MRCP was found highly specific in differentiating the calcular, malignant and benign causes of obstruction.  The quality of images were degraded by the presence of massive ascites, marked patient obesity in our study by the instability to hold breath in a reproducible manner. Lack of the therapeutic role and the inability to perform functional studies mainly at the papilla remain the main limitation of the technique. Conclusion: MRCP should be the next step following depiction of biliary obstruction by U/S. Consequently in the near future there will be no place for the diagnostic use of the ERCP which shall be then restricted to a therapeutic role.