[Pitfalls during ultrasonography investigation of the carotid arteries (author's transl)].

The authors describe the principal pitfalls and sources of error encountered during the application and interpretation of continuous ultrasonography examinations of the carotid artery. These include poor examination technique, limitations of the ultrasonography examination, and incorrect interpretation of results. The effects of these errors in relation to each segment of the carotid axis are discussed, and the importance of comparing the results obtained with those of palpation and auscultation of the cervical region is emphasized. The greatest difficulty is the certain recognition of a pathological signal from the internal carotid artery: acceleration, turbulence, absence of signal. This latter anomaly may be present both when there exists an occlusion of the internal carotid artery and a pseudo-occlusive stenosis of this artery. The difference is fundamental from the therapeutic point of view. Ultrasonography does not therefore replace arteriography but can assist the decision to undertake urgent or delayed operative therapy.