CT and sonography are helpful in distinguishing between an obstructing lesion and hepatocellular disease as the cause of jaundice. 2. CT and sonography can demonstrate the level and extent of an obstructing lesion, and can define its nature if a mass more than 1-2 cm is present; sonography is usually the preferred screening study because of its availability, relatively low cost and lack of radiation hazard. 3. PTC or ERCP is useful in the evaluation of jaundice when sonography and CT are equivocal, fail to provide information necessary to establish proper therapy, or are at variance with the clinical impression of obstructive jaundice; in addition to defining obstructions these techniques can detect atrophy, sequestra, stones, abscesses, fistulas, primary sclerosing cholangitis, etc. 4. PBD offers an expedient alternative to surgical decompression in patients with obstructive jaundice, since most cancers that cause biliary obstruction are not resectable for cure at the time of diagnosis.
