ROLE OF ULTRASOUND AND MRCP IN DETERMINING THE LEVEL AND CAUSE OF BILIARY OBSTRUCTION IN PATIENTS WITH OBSTRUCTIVE JAUNDICE

Abstract

Background: Biliary obstruction is a common clinical condition that can result from both benign and malignant causes, including choledocholithiasis, strictures and tumors of the pancreas or periampullary region. Early and accurate identification of the level and cause of obstruction is essential to guide appropriate management and prevent complications such as cholangitis, biliary cirrhosis and hepatic failure. Imaging plays a crucial role in diagnosis, with ultrasound being widely available and cost-effective, while magnetic resonance cholangiopancreatography (MRCP) provides detailed non-invasive evaluation of the biliary and pancreatic ducts.

Objective: To assess and compare the diagnostic accuracy of ultrasound and MRCP in identifying the level and cause of biliary obstruction in patients with obstructive jaundice.

Methodology: A cross-sectional study was conducted at Muhammad Islam Teaching Hospital, Gujrawala, including 60 adult patients with suspected obstructive jaundice. All participants underwent abdominal ultrasonography and MRCP using a TOSHIBA Vantage Elan 1.5T MRI system to determine the level and cause of biliary obstruction. Patients with metal implants, pacemakers, cochlear devices or severe claustrophobia were excluded. Data were analyzed using SPSS version 26. Diagnostic performance of MRCP and ultrasound was assessed through sensitivity, specificity, positive predictive value and negative predictive value. McNemar’s test was applied to compare the detection rates of both modalities, with p < 0.05 considered statistically significant.

Results: This cross-sectional study included 60 patients with obstructive jaundice, of whom 61.7% were females and 38.3% were males, with the majority aged between 42 and 76 years. MRCP detected obstruction in 59 of 60 patients (98.3%) with a positive predictive value of 100%, identifying distal CBD involvement most frequently (32 cases). Ultrasound detected obstruction in 34 of 60 patients (56.7%), missing 26 cases and showed variable sensitivity depending on the cause and level of obstruction. The most common causes were cholelithiasis with choledocholithiasis (22), choledocholithiasis alone (16), pancreatic head tumors (5) and CBD strictures (5). Cross-tabulation revealed that 33 patients were positive on both MRCP and USG, 26 were positive only on MRCP and one patient was positive only on USG. McNemar testing confirmed a statistically significant difference between the modalities (p < 0.001), demonstrating the superior diagnostic performance of MRCP.

Conclusion: MRCP is a highly sensitive and reliable modality for determining both the level and cause of biliary obstruction, outperforming ultrasound in detecting distal CBD lesions and pancreatic pathologies. Ultrasound, while valuable as a first-line screening tool, shows limited sensitivity in certain obstructions and should be complemented by MRCP for accurate diagnosis.