DUPLEX SCANNING IN EVALUATING STENOTIC LESIONS IN THE CAROTID VESSELS - EITHER DISTAL OR PROXIMAL TO THE COMMON CAROTID BIFURCATION.

Duplex ultrasound scanning (7. 5-10 MHz real time B-mode coupled with a 3-5 MHz pulsed Doppler) has been well documented in its ability to grade stenotic lesions at the carotid bifurcation. Potential limitation of using this system is missing distal internal carotid artery lesions involving the upper cervical or cavernous portion of the internal carotid artery or proximal common carotid artery lesions. In a retrospective review over the past two years, twelve cases were found which demonstrate lesions in the distal internal carotid artery or at the origin of the common carotid arteries. All lesions involving the distal internal carotid artery had an eighty percent or greater stenosis except for one lesion which demonstrated a sixty percent diameter stenosis. This retrospective review suggests the system is insensitive to lesser degrees of stenosis than eighty percent. Pitfalls of interpreting proximal and distal lesions are discussed.