Biliary dilatation--the accuracy of ultrasound in determining the cause.

This study reviewed the findings from ultrasound reports and medical notes of 303 patients examined by ultrasound between January 1985 and December 1987. It established the accuracy with which ultrasound could diagnose the cause of obstructive jaundice at 49.5%. A correlation was discovered between the actual pathology causing the obstruction and biliary dilatation and the degree to which the common duct became dilated. Further research into this area using a greater number of statistics is required before this can be applied in a clinical situation, but generalisations were formulated and could be used as guidelines to suggest, rather than state, the possible cause of the common duct obstruction. The following mean diameters for seven pathologies were established: duodenal (8.4 mm); cholecystitis (8.7mm); cholecystectomy (9.5mm); lymph nodes (9.5mm); pancreatitis (9.8mm); duct stones (11.0 mm); and pancreatic carcinoma (14 mm).