Ultrasonography is the most useful technique for screening patients with suspected obstructive jaundice. Additional information may be gained with CT when US fails either because of disturbing gas-filled loops of bowel or because the patient is obese. A more specific diagnosis is usually obtained from the ERCP which can be combined with percutaneous biopsy and drainage of obstructed bile ducts. PTC and PTCD are left for those patients in whom ERCP has failed.