Ultrasonic imaging in the diagnosis of extracranial carotid artery disease.

Basically two principles have to be distinguished in ultrasonic imaging of arteries. In velocity imaging blood flow velocities are visualized with continuous wave or pulsed Doppler devices. In pulsed echo-systems artery wall structures are visualized by picking up echoes reflected by the vessel walls. Velocity imaging is mainly used to localize the site of velocity sampling which is of importance in screening the carotid artery bifurcation and in follow-up studies. Although promising results have been obtained in diagnosing atherosclerotic lesions with echo-imaging systems, these systems have their limitations. To improve the diagnostic accuracy these systems should be combined with a single- or multi-gate pulsed Doppler system.