Fulltext

CT angiography helps to differentiate acute from chronic carotid occlusion: the "carotid ring sign”

Michel, Patrik ; Ntaios, George ; Delgado, Montserrat ; Bezerra, Daniel ; Meuli, Reto ; Binaghi, Stefano

In: Neuroradiology, 2012, vol. 54, no. 2, p. 139-146

Ajouter à la liste personnelle
    Titre
    • CT angiography helps to differentiate acute from chronic carotid occlusion: the "carotid ring sign”
    Auteur
    • Michel, Patrik. Neurology Service, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Rue De Bugnon 46, CH 1011, Lausanne, Switzerland
    • Ntaios, George. Neurology Service, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Rue De Bugnon 46, CH 1011, Lausanne, Switzerland
    • Delgado, Montserrat. Hospital Universitario Central de Asturias, Oviedo, Spain
    • Bezerra, Daniel. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
    • Meuli, Reto. Department of Radiology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
    • Binaghi, Stefano. Department of Radiology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
    Type de document
    • Postprint
    Identifiant OAI-PMH
    • oai:doc.rero.ch:321494
    Summary
    Introduction: Currently, there is no reliable method to differentiate acute from chronic carotid occlusion. We propose a novel CTA-based method to differentiate acute from chronic carotid occlusions that could potentially aid clinical management of patients. Methods: We examined 72 patients with 89 spontaneously occluded extracranial internal carotids with CT angiography (CTA). All occlusions were confirmed by another imaging modality and classified as acute (imaging <1week of presumed occlusion) orchronic (imaging >4weeks), based on circumstantial clinical and radiological evidence. A neuroradiologist and a neurologist blinded to clinical information determined the site of occlusion on axial sections of CTA. They also looked for (a) hypodensity in the carotid artery (thrombus), (b) contrast within the carotid wall (vasa vasorum), (c) the site of the occluded carotid, and (d) the "carotid ring sign” (defined as presence of a and/or b). Results: Of 89 occluded carotids, 24 were excluded because of insufficient circumstantial evidence to determine timing of occlusion, 4 because of insufficient image quality, and 3 because of subacute timing of occlusion. Among the remaining 45 acute and 13 chronic occlusions, inter-rater agreement (kappa) for the site of proximal occlusion was 0.88, 0.45 for distal occlusion, 0.78 for luminal hypodensity, 0.82 for wall contrast, and 0.90 for carotid ring sign. The carotid ring sign had 88.9% sensitivity, 69.2% specificity, and 84.5% accuracy to diagnose acute occlusion. Conclusion: The carotid ring sign helps to differentiate acute from chronic carotid occlusion. If further confirmed, this information may be helpful in studying ischemic symptoms and selecting treatment strategies in patients with carotid occlusions