Limitation of Magnetic Resonance Cholangiopancreatography in The Evaluation of Biliary Tree Pathology

Objective: Many pitfalls have been encountered in evaluation of Magnetic Resonance Cholangiopancreatography (MRCP) images that alter its diagnostic accuracy, the awareness of these pitfalls help in avoiding misinterpretation of images.Patients and Methods: From the 234 patients, this retrospective study including 24 patients with false MRCP diagnosis compared with Endoscopic Retrograde Cholangiopancreatography ERCP, MRCP examinations were performed using a multi section turbo spin-echo sequence. The data obtained from Maximum Intensity Projection (MIP) image was correlated with the source image and other MRI sequences.Results: Overall sensitivity, specificity, positive, negative predictive values and accuracy of MRCP in detecting biliary obstruction compared with ERCP measured 93%, 87%, 92% and 89% and 90% respectively. From the 234 patients, there are 24 (9%) misdiagnosed cases by MRCP as false positive n=17 (71%) and false negative n=7 (29%) cases. According to underlying cause of misdiagnosis those related to extraductal factor was accounted for most of recorded pitfalls resulting in 9 (37%) cases, followed by the technical factors 7 (29%) cases, anatomical variants that simulates pathology 6 cases (25%) and factors related to intraductal cause in 2 (8%) cases.Conclusion: MRCP was accurate non invasive technique for evaluation of biliary pathology with diagnostic accuracy comparable to ERCP, the understanding of causes resulting in misinterpretation help in increasing its accuracy.