Unraveling Obstructive Jaundice: A Comparative Analysis of USG and MRCP

Abstract

 Background: Obstructive jaundice, caused by mechanical blockage in the biliary system, presents a common diagnostic challenge in gastrointestinal and hepatobiliary medicine. Early and accurate identification of the underlying etiology and level of obstruction is vital for guiding treatment. Ultrasonography (USG) is often used as the first-line imaging modality due to its accessibility and cost-effectiveness, whereas Magnetic Resonance Cholangiopancreatography (MRCP) has emerged as a superior non-invasive technique for detailed evaluation of the biliary tract. Objective: To compare the diagnostic efficacy of USG and MRCP in identifying the cause and location of obstructive jaundice, and to assess their respective sensitivity, specificity, and overall diagnostic accuracy. Methods: A prospective observational study was conducted involving 40 patients with clinical and biochemical features of obstructive jaundice. Each participant underwent both USG and MRCP using standardized protocols. Imaging results were evaluated against clinical findings and, when available, ERCP data. Diagnostic metrics including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were computed. Results: Of the 40 patients, choledocholithiasis was the most common cause (52%), followed by CBD stricture (15%) and periampullary carcinoma (7%). MRCP demonstrated superior diagnostic performance with a sensitivity of 94.87%, specificity of 50%, PPV of 97.42%, NPV of 20%, and accuracy of 92.68%. In comparison, USG yielded a sensitivity of 67.75%, specificity of 33.3%, PPV of 86.6%, NPV of 10%, and accuracy of 65%. MRCP was particularly effective in detecting distal CBD lesions and rare entities like Lemmel syndrome. Conclusion: MRCP is significantly more accurate than USG in diagnosing both benign and malignant causes of obstructive jaundice. While USG remains a valuable initial screening tool, MRCP should be considered essential for comprehensive diagnostic assessment and treatment planning.