[Traps in hepatobiliary echotomography caused by technical artifacts and the method of evading them].

Errors encountered during evaluation of hepatobiliary ultrasonography explorations due to various artefacts are described. These are mainly due to the problem of the lateral resolution of ultrasonographic recordings leading to false negatives and positives during diagnosis of the pathological process, lithiasis and cholecystitis. These are also the cause of errors during ultrasound guiding of needle punctures and thus the precision of the explorations. The major problem of echogenetic resolution is raised as this is also a cause of numerous artefacts, though it is much more difficult to evaluate their importance. Suggestions are made concerning the use of equipment for conducting explorations with the minimum of error, and the techniques to be employed.