The early diagnosis of common bile duct obstruction using cholescintigraphy

The technetium Tc 99m-labeled iminodiacetic acid cholescintigram is an extremely accurate examination for detecting early obstruction of the common bile duct in acutely ill patients suspected of having acute cholecystitis or possible obstruction days to years after cholecystectomy. The examination accurately detected common bile duct obstruction in 63 of 65 patients in these two diagnostic categories (positive predictive value, 96.9%). Sonographic evaluations in 43 of these patients failed to reveal ductal dilatation or other abnormality in 26 cases (false-negative rate, 63.4%), and was nondiagnostic because of overlying bowel gas in two cases. The success of the radionuclide examination is attributed to its ability to detect functional impedance to bile flow hours to days before anatomic ductal dilatation occurs, and occasionally even before the alkaline phosphatase level and other liver chemistry values suggest the presence of an obstruction.