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

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

doi:10.1007/s00234-011-0868-9

Cited by 20 publications

(14 citation statements)

References 13 publications

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“…A previous study, based on circumstantial clinical and radiological imaging data, defined chronic occlusion as occlusion lasting more than 4 weeks ( 5 ). Chronic occlusion may be distinguished from acute occlusion by computed tomography (CT) angiography (CTA), as the ‘carotid ring sign’ (defined as the presence of hypodensity in the ICA and/or contrast within the carotid wall) is visible in CTA of acute ICA occlusion ( 4 ). Another study suggested, according to current data in the field of cardiovascular medicine, that the minimum threshold for chronic total occlusion (CTO) of the ICA should be at least 3 months, and possibly even more than six months ( 5 ).…”

Section: Introductionmentioning

confidence: 99%

Current understanding of chronic total occlusion of the internal carotid artery (Review)

Guo

et al. 2017

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At present, there is limited understanding of chronic total occlusion (CTO) of the internal carotid artery (ICA). Therefore, the present report collected related cases from PubMed and reviewed the literature. Cerebral vessels may form collateral circulation immediately or gradually following CTO of the ICA. The natural history of CTO of the ICA includes a variety of outcomes, all of which are biased toward a non-benign progressive process and are characterized by insufficient cerebral perfusion, embolus detachment and cognitive dysfunction. The majority of cases of CTO of the ICA require treatment. In early studies, the results of external-ICA bypass were unsatisfactory, while recanalization is now considered the only viable option. The current treatment indications mainly depend on the degree of injury to the cerebrovascular reserve and the extent to which the oxygen extraction fraction is increased. The length, height and duration of ICA occlusion are also relevant, though more frequently, the condition depends on multiple factors. Endovascular interventional recanalization, carotid endarterectomy (CEA) and hybrid surgery may be conducted in a select group of patients. As novel materials are developed, the success rate of simple recanalization may gradually increase; however, hybrid surgery may be more representative of the current trend, as advanced CEA can remove carotid atherosclerosis plaques, thus reducing the technological demands of the subsequent interventional recanalization. There are many complications that may result from recanalization following CTO of the ICA, including hyperperfusion and technical errors; therefore, the operation must be conducted carefully. If the recanalization is successful, it typically results in a stable improvement of patient condition in the long term. However, despite these conclusions, more studies are required in the future to further improve current understanding of CTO of the ICA.

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Section: Introductionmentioning

confidence: 99%

Current understanding of chronic total occlusion of the internal carotid artery (Review)

Guo

et al. 2017

biom rep

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“… 11 – 13 Some studies confirmed the moderate or strong agreement between the neurologist and radiologist in case of proximal or distal occlusion of ICA or in case of CTA perfusion evaluation. 9 , 10 …”

Section: Discussionmentioning

confidence: 99%

“… 8 Therefore, in our study we intended to assess the interrater agreement of the diagnosis of occlusion of intracranial arteries at CTA between a radiologist, a general neurologist and a neurologist-stroke specialist. Some previous studies confirmed the moderate or strong agreement between a neurologist and a radiologist in case of proximal or distal occlusion of the internal carotid artery (ICA) or in case of CTA perfusion evaluation, 9 , 10 but the agreement has not been tested in the case of CTA which was performed before recanalization therapy.…”

Section: Introductionmentioning

confidence: 99%

Interrater variability for CT angiography evaluation between neurologists and neuroradiologist in acute stroke patients

Bar

Král

Jonszta

et al. 2017

The British Journal of Radiology

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Objective:The diagnosis of arterial occlusion has a considerable impact on the indication of mechanical thrombectomy, and CT angiography (CTA) is recommended in the management of acute stroke. The goal of the present study is to assess the interrater agreement in the diagnosis of occlusion of intracranial arteries on CTA between a neuroradiologist and neurologists.Methods:CTA images of 75 acute stroke patients were evaluated for occlusion of intracranial arteries by an experienced interventional neuroradiologist, and stroke and general neurologists.Results:75 patients who were treated by intravenous thrombolysis were enrolled in the study. CTA images were available for all 75 patients (34 females; mean age ± SD, 72 ± 14 years; National Institutes of Health Stroke Scale 10; median 8–14; and Alberta Stroke Program Early CT mean 9.7). The agreement between the neuroradiologist and neurologists in evaluation of intracranial artery occlusion was as follows: occlusion of the middle cerebral artery segment M1: observer agreement 77%, kappa (κ) = 0.61 and middle cerebral artery M2: observer agreement 77%, κ 0.48; internal carotid artery: observer agreement 92%, κ 0.84; T occlusion: observer agreement 90.0%, κ 0.33; posterior cerebral artery segments P1 and P2: observer agreement 98%, κ 0.97; basilar artery: observer agreement 96%, κ 0.92; and vertebral artery segment V4: observer agreement 88%, κ 0.48.Conclusion:Interrater agreement of CTA evaluation of occlusion between the neurologists and the neuroradiologist was very strong. The ability of the trained neurologists to read an intracranial large vessel occlusion correctly may improve the door-to-needle times in acute stroke.Advances in knowledge:In this study, the neurologists were able to recognize occlusion of intracranial arteries. This could accelerate the management of acute stroke care.

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“…[41][42][43][44] Perfusion or rather postcontrast imaging since dynamic imaging at the moment would provide a too low resolution is possible also with CT and MR. One example where enhanced imaging has been of help is the so-called carotid ring sign that helps to differentiate acute from chronic occlusions. 45 From a radiological point of view, the degree of stenosis from which treatment will be decided is usually done by using the NASCET or ECST criteria, with measurements done on the images in a sagittal projection. While this applies to plaque measurements, further criteria for the evaluation before treatment may be taken into account such as plaque progression (following stenosis degree on multiple followup examinations) or also by looking at plaque morphology.…”

Section: Extracranial Carotid Artery Diseasementioning

confidence: 99%

The role of advanced neuroimaging techniques in ischemic stroke prevention

Lövblad

Bouchez

Altrichter

et al. 2019

Clinical and Translational Neuroscience

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In great part due to recent advances in medical technology, ischemic cerebral stroke has become an increasingly treatable condition, which requires urgent measures and which rely on pharmacological and/or interventional measures. Due to its high prevalence, preventive measures should also be undertaken, and this is a situation where the use of advanced neuroimaging techniques could be helpful in certain underlying diseases. What is proposed here is to discuss how modern neuroimaging techniques (advanced magnetic resonance (MR) techniques and/or nuclear medicine techniques such as positron emission tomography (PET)) could help in situations that would otherwise lead to a stroke. Since both primary and secondary prevention measures are often required, we see that the techniques can be helpful in both situations. The diseases that cause stroke that can be investigated are, among others, carotid stenosis; transient ischemic attacks (TIAs) may also be followed by a major stroke if nothing is undertaken. It has been established that carotid stenosis is to be treated in the presence of a significant lesion that has neurological symptoms. The question of how to deal with these patients often arises when the relationship between the stenosis and symptoms is not significant or the symptomatology unclear. In such situations, either PET and/or fat-saturated T1 images of the carotids can help to demonstrate the embolic nature of the plaque. We have seen that carotid plaque vulnerability, which can cause embolism, can be associated with plaque inflammation (seen on PET) or plaque haemorrhage (seen on MR images). Also, while PET and MRI will demonstrate different stages of plaque vulnerability, they can both help to demonstrate vascular lesions that are at risk of causing significant ischemic events. Diffusion-weighted imaging (DWI) has shown that some TIAs may indeed be ischemic brain lesions with a transient symptomatology. The early use of DWI can thus help treat these patients more acutely. Based on this, we have seen that newer imaging techniques can provide additional knowledge about conditions that may lead to stroke and be treated. This should have a major impact on patient outcomes and ultimately on healthcare costs related to this condition.

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

Abstract: 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.

Cited by 20 publications

References 13 publications

Current understanding of chronic total occlusion of the internal carotid artery (Review)

Current understanding of chronic total occlusion of the internal carotid artery (Review)

Interrater variability for CT angiography evaluation between neurologists and neuroradiologist in acute stroke patients

The role of advanced neuroimaging techniques in ischemic stroke prevention

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