Rule-out and rule-in of carotid near-occlusion using color duplex ultrasound

• Published in: Neuroradiology Vol. 67; no. 5; pp. 1223 - 1231
• Main Authors: Skoog, Johan, Vanoli, Davide, Henze, Alexander, Fox, Allan J., Johansson, Elias
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2025; Springer Nature B.V
• Subjects: Aged; Angiography; Blood Flow Velocity; Carotid arteries; Carotid artery; Carotid near-occlusion; Carotid stenosis; Carotid Stenosis - diagnostic imaging; Cerebral blood flow; Color; Colour duplex ultrasound; Computed Tomography Angiography; Criteria; Cross-Sectional Studies; CT angiography; Diagnostic Neuroradiology; Female; Humans; Imaging; Ischemia; Magnetic resonance; Male; Medical imaging; Medicine; Medicine & Public Health; Middle Aged; Neurology; Neuroradiology; Neurosciences; Neurosurgery; Neurovetenskaper; Occlusion; Parameter sensitivity; Prospective Studies; Radiology; Sensitivity and Specificity; Sorting algorithms; Stenosis; Stroke; Ultrasonic imaging; Ultrasonography, Doppler, Color - methods; Ultrasound; Velocity; Carotid stenosis; CT angiography; Stroke; Carotid near-occlusion; Colour duplex ultrasound
• ISSN: 0028-3940; 1432-1920; 1432-1920
• DOI: 10.1007/s00234-025-03612-2

Purpose Diagnosing carotid near-occlusion (CNO) with colour duplex ultrasound (CDU) is challenging. We hypothesised that CNO is associated with a reduced distal internal carotid artery (ICA) velocity and aimed to assess if distal velocity is able to diagnose CNO accurately. If not, we aimed to develop CDU rule-out and rule-in criteria to diagnose CNO. Methods This is a prospective cross-sectional study in consecutive participants with suspected ≥ 50% carotid stenosis on CT angiography (CTA). CDU velocities in the common carotid artery, the stenosis and distal to the stenosis were examined. CTAs were assessed for CNO, serving as a reference test. If no CDU parameter was both sensitive and specific for CNO, rule-out (98% sensitive) and rule-in (99% specific) criteria were created. Results Of the 315 included participants with ≥ 50% stenosis, 190 (60%) were conventional ≥ 50% stenosis and 125 (40%) CNO. No CDU parameter was both sensitive and specific for CNO. The best exclusion criteria were stenosis end diastolic velocity (EDV) ≤ 63 cm/s and/or distal peak systolic velocity (PSV) > 23 cm/s, seen in 115 (38%) participants. The best rule-in criteria were stenosis EDV ≥ 280 cm/s and/or distal PSV ≤ 23 cm/s, seen in 35 (12%) participants. Of the remaining participants, 143 (47%) were uncertain (74 CNOs) and 9 (3%) were misdiagnosed as carotid occlusion (all CNOs). Conclusions CDU alone cannot diagnose CNO but can rule in or rule out CNO in half of participants with ≥ 50% stenosis. These criteria are intended for inclusion in an algorithm, sorting cases needing further exams, such as CTA and/or phase-contrast magnetic resonance angiography.