Usefulness of diagnostic tests for biliary obstruction.

We studied the value of tests commonly used in diagnosing obstructive jaundice in 188 patients operated on for biliary obstruction. Ultrasonography had a diagnostic accuracy of 87 percent for gallbladder stones, 82 percent for dilated ducts, and 80 percent for pancreatic masses. Computed tomography was 93 percent accurate in diagnosing dilated ducts, and 93 percent accurate in diagnosing a pancreatic mass. Intravenous cholangiography gave useful information in only 4 of 21 patients. Among 45 patients, endoscopic retrograde cholangiopancreatography was technically successful in 91 percent and gave accurate diagnostic information in 86 percent and partially diagnostic information in 7 percent; it detected all cases of common duct stones and had a 91 percent sensitivity for detecting pancreatic cancer. Among 75 patients, transhepatic cholangiography was technically successful in 95 percent and provided accurate diagnostic information in 90 percent and partially diagnostic information in 3 percent; it detected all cases of common duct stones and 95 percent of cases of benign strictures. With persistent jaundice, ultrasonography should be the first test because it is less costly than computed tomography and provides similar information. If more information is needed, transhepatic cholangiography and endoscopic retrograde cholangiopancreatography are equally accurate; transhepatic cholangiography more often opacifies the proximal biliary tree and endoscopic retrograde cholangiopancreatography provides direct access to the ampulla of Vater and the pancreatic duct.