Detection of early atherosclerotic lesions by duplex scanning of the carotid artery.

A high-resolution ultrasound B-mode imaging system combined with a 16-sequential range-gated pulsed Doppler flow measuring device was used for the evaluation of nonstenotic extracranial carotid artery disease. Various types of atherosclerotic lesions were differentiated by Duplex system examinations in 54 carotid arteries examined in vitro in a postmortem study and in 51 carotid arteries examined in vivo from patients with angiographically proven cerebrovascular disease. In addition, the multigated Doppler system allowed the analysis of flow velocity profiles throughout the carotid arteries, the distinction between intraarterial flow and recent thrombus, and in particular the estimation of local flow alterations, which are diagnostic in the presence of sonolucent and shadowed plaques behind echo-dense lesions. A number of difficulties, which at present limit the application of Duplex system examination as a non-invasive "stand alone" method for detecting carotid disease, are discussed.