[Ultrasonic diagnosis of bile duct calculi. A prospective study regarding the effects and the objective and subjective factors on accuracy in choledocholithiasis]

Abstract

The reliability and diagnostic sensitivity of the sonographic identification of bile duct concrements is mainly determined by the examiner's competence and the size of the concrements, and secondly also by the diameter or patency of the bile ducts. Basing on the records of 175 patients on whom choledocholithiasis had been performed, a prospective study (reference: concrement removal after ERCP) showed that the sensitivity of the method is almost twice as high with an experienced examiner than with a less experienced physician (80% vs. 47%). In 231 other cases with extrahepatically conditioned cholestasis we found a 93% specificity of sonography in respect of excluding the presence of concrements. 93% of the concrements that were bigger than 10 mm were definitely diagnosed via sonography (71% sensitivity in case of concrements < 10 mm). If the proof of presence of concrements is differentiated according to bile duct width, it is seen that 85% of all concrements were visualised if the width of the ductus choledochus was > or = 8 mm and 71% in case of a width < 8 mm. The results of the study justify the use of sonography as a primary method in the diagnosis of concrements of the bile ducts; under certain conditions it is also possible to exclude the presence of stones. If findings do not agree with the clinical pattern of findings, or if the bile ducts cannot be visualised properly, diagnostic ERCP is indicated.