Detection of XXXX , string sign, and preocclusive stenosis of the internal carotid artery by color-flow duplex scanning.

@entity75 @entity1 @entity64 @entity432
BACKGROUND: @entity64 prevention depends on the accurate differentiation of surgically treatable @entity75 from total occlusions of the internal carotid artery. This prospective study was undertaken to review the accuracy of colorflow duplex scanning for identifying carotid string signs, @entity75 (95% to 99% stenoses), and @entity432 of the internal carotid artery. MATERIALS AND METHODS: Over an 18-month period, 4,362 @entity1 underwent color-flow duplex scanning of the carotid arteries. Angiograms of 596 internal carotid arteries were available for comparison with the duplex scan findings. Total occlusion was diagnosed by the absence of flow in internal carotid arteries visualized on B-mode scanning. @entity75 were identified by a trickle of flow in the vessel lumen. RESULTS: Of 65 color-flow duplex scans that predicted @entity432 , 64 (98%) were confirmed by angiography. The negative predictive value for @entity432 was 99%. Twenty-six (87%) of 30 string signs and focal 95% to 99% stenoses were correctly identified. Color-flow scanning prediction of @entity75 was accurate in 84% of 31 cases. Low velocities in the internal carotid artery were usually associated with a string sign, and high velocities with a focal @entity75 . CONCLUSIONS: Color-flow duplex scanning accurately differentiates between stenotic and totally occluded internal carotid arteries. Identification of @entity75 is not as accurate but the results are promising. Arteriographic confirmation of duplex scan findings is necessary only when scans are equivocal.
