Role of Magnetic Resonance Cholangiopancreatography and Ultrasound as a Diagnostic Tool in Suspected Cases of Biliary Obstruction: A Prospective Cohort Study

Introduction: Obstructive jaundice is a common and grave form of hepatobiliary disease. It can pose problems in diagnosis and management, particularly intrahepatic cholestasis. Magnetic Resonance Cholangiopancreatography (MRCP) and Ultrasound (USG) are the frontline modality for biliary and pancreatic duct imaging. Aim: To evaluate the accuracy of USG and MRCP in assessing the level and cause of biliary obstruction which were compared with pathological or surgical findings. Materials and Methods: This prospective cohort study was conducted in the Department of Radiodiagnosis in a teriary care hospital from August 2013 to August 2015. Total 60 patients who were referred from the Department of Surgery and Medicine with strong clinical suspicion of biliary obstruction and altered Liver Function Test (LFT) were included in the study. All these patients underwent USG examination within a day of MRCP. Patients with previous biliary surgery and in whom Magnetic Resonance Imaging (MRI) was contraindicated were excluded. As a gold standard, the authors used ERCP, histological test and pathological findings after surgical intervention. The data collected was statistically analysed; sensitivity and specificity were calculated by using true and false positive and/or negative fractions. Results: The majority of patients were females and in sixth decade of life. The diagnostic accuracy of USG in detecting level of obstruction was comparable with MRCP. USG was 100% accurate in detecting hilar and suprapancreatic obstructions. In infrapancreatic obstructions diagnostic accuracy of USG was 95% as pancreatic head and peripancreatic region are poorly visualised on ultrasonography due to bowel gas shadows. Diagnostic accuracy of USG in the present study was 98.3%, one false negative case was of a small, soft, 4 mm calculus in distal Common Bile Duct (CBD). Sensitivity and specificity of USG in differentiating cystic from solid masses was 100%. Conclusion: The USG with improved technology and operator experience should be considered as the first choice in the diagnostic imaging of obstructive biliary disease. If the suspicion posed by clinical and laboratory findings are not confirmed at USG, the diagnosis must be achieved with the aid of MRCP.