Carotid near-occlusion can be identified with ultrasound by low flow velocity distal to the stenosis. (March 2019)

• Record Type: Journal Article
• Authors: Johansson, Elias; Benhabib, Hadas; Herod, Wendy; Hopyan, Julia; Machnowska, Matylda; Maggisano, Robert; Aviv, Richard; Fox, Allan J
• Is Part Of: Acta radiologica. Volume 60:Number 3(2019)
• Page Start: 396
• Page End: 404
• Publication Date: 2019-03
• Subjects: Stroke -- carotid stenosis -- near-occlusion -- CT angiography -- ultrasound -- distal velocity; Radiology, Medical -- Periodicals; Radiography, Medical -- Periodicals; Radiotherapy -- Periodicals; 616.0757
• DOI: 10.1177/0284185118780900
• Languages: English
• ISSNs: 0284-1851

Abstract

Background: Most carotid near-occlusions are indistinguishable from conventional ≥ 50% stenosis on ultrasound, demonstrating high peak systolic velocity (PSV) in the stenosis. Purpose: To study whether the velocity distal to the stenosis can separate high PSV near-occlusion from conventional ≥ 50% stenosis. Material and Methods: We included patients with ≥ 50% carotid stenosis with high PSV (≥125 cm/s), examined with both computed tomography angiography (CTA) and ultrasound within 30 days, and a distal velocity measurement was performed. Based on CTA, cases were divided into three groups: conventional stenosis; near-occlusion without full collapse (NwoC; normal-appearing albeit small distal artery); and near-occlusion with full collapse (NwC; threadlike distal artery). Distal Doppler ultrasound flow velocities were compared between these groups. Results: Sixty patients were included: 33 patients with conventional stenosis; 20 patients with NwoC; and seven patients with NwC. Mean distal PSV was 93, 63, and 21 cm/s ( P < 0.001) and mean distal end-diastolic velocity was 30, 24, and 5 cm/s ( P < 0.001), respectively. A distal PSV < 50 cm/s was 63% sensitive and 94% specific for separating both types of near-occlusion from conventional stenosis. Conclusion: In high PSV carotid stenoses, the distal velocity was lower in near-occlusions than conventional carotid stenosis. Distal velocities warrant further investigation in diagnostic studies.