Ultrasonographic findings in obstructive jaundice: the ability of ultrasound to accurately determine the site and cause of obstruction

Abstract

The ability of ultrasound to accurately distinguish obstructive jaundice from nonobstructive jaundice has made sonography the accepted screening procedure in the jaundiced patient. Determination of the anatomic site of obstruction and its cause is critical in the management of the jaundiced patient, whether traditional surgical therapies are contemplated or newer "nonsurgical therapies like" radiologic methods are instituted. Choosing the correct therapy and obtaining the best results from that therapy usually require a precise knowledge of anatomic detail and the nature and extent of the disease. The high accuracy and relative safety of direct cholangiography and newer imaging methods such as magnetic resonance cholangiopancreatography have set a high standard against which sonography must compete. Objectives The main objective was to evaluate the capacity of ultrasound in determining the site and cause of obstructive jaundice. Study design A descriptive prospective study. Setting Kenyatta National Hospital and University Of Nairobi radiology departments. Subjects All patients with obstructive jaundice who had undergone U/S examination and another diagnostic imaging test /surgery with which the results of U/S were compared. Methods A total of 40 patients with evidence of intrahepatic or extra hepatic obstruction were entered prospectively into the study from June 2007 to April 2008. Results The site of obstruction was predicted in 26 patients (sensitivity of 65% and specificity of 77%), but was indeterminate in 35% because of the inability to visualize the complete biliary tract. The cause of obstruction was correctly predicted in 31 patients (sensitivity of 78% and specificity of 72%) and was indeterminate in 22% (p<O.05). Conclusion Ultrasonography was accurate in differentiating obstructive from non obstructive jaundice but was non specific in assigning a definite cause of obstruction and in predicting the site of obstruction