Tricky and interesting carotid cases.

In many instances, ultrasound examination of the carotid arteries is a straightforward matter, with easily recognized atherosclerotic disease and well-defined parameters for assessment of carotid obstruction. In some circumstances, however, hemodynamic conditions may skew the Doppler velocity and waveform findings in potentially confusing ways, possibly cause misdiagnosis. This is the "tricky" aspect of carotid sonography of which all vascular ultrasound practitioners must be wary. A series of cases are presented in this article, representing common diagnostic problems seem in day-to-day clinical practice that may trick the unwary diagnostician. These cases are presented as "unknowns," allowing the reader to analyze the findings and attempt to recognize the diagnostic pitfall. Each case is followed by analysis of the findings and listing of key diagnostic points.