Carotid Artery Calcification on CT May Independently Predict Stroke Risk

Abstract

OBJECTIVE-The purpose of our study was to quantitatively evaluate calcified atherosclerotic burden in the cervical carotid arteries using MDCT to determine the relationship of scores with luminal stenosis and symptomatology.MATERIALS AND METHODS-Calcium plaque volume was measured in 106 cervical carotid arteries (53 patients) using MDCT angiography. The study group included 32 asymptomatic patients (mean age, 70.2 ± 8.7 [SD] years; 15 women, 17 men) and 21 patients with ischemic neurologic symptoms (69.6 ± 12.9 years; eight women, 13 men). By vessel, there were 43 high-grade stenotic (≥ 60% by North American Symptomatic Carotid Endarterectomy Trial [NASCET] criteria), 15 moderate-grade stenotic (30-59%), and 44 mild-grade stenotic or normal (0-29%) vessels, with four excluded for prior carotid endarterectomy. Volume scores were calculated by summing the area of calcium in the common and extracranial internal carotid arteries on axial slices and multiplying by the slice increment.RESULTS-Controlling for cardiovascular risk factors and luminal stenosis, we found that scores were significantly related to the occurrence of symptoms (p = 0.003). Even with patient age as a covariant, patients with high-grade stenosis had significantly higher scores than those without highgrade disease (p = 0.004). Moreover, quantitative burden was associated with luminal stenosis on adjusted multivariate analysis (p = 0.034). The specificity and positive predictive value for highgrade luminal narrowing were notably lower on individual vessel analysis than on total score analysis, likely secondary to variability in vascular remodeling.CONCLUSION-Calcium scores in the cervical carotid arteries may represent an independent marker for luminal stenosis and ischemic symptoms. A prospective longitudinal study examining calcium levels and morbidity may be warranted to examine whether burden has a role in risk stratification. KeywordsCT arteriography; calcium; carotid; stroke Vascular calcium deposits have recently become a major research and public interest secondary to increasing evidence of the relationship of calcium scores with atherosclerotic burden and clinical outcome. The prevailing example involves coronary calcium scores measured on CT, which have been associated with luminal stenosis [1], overall coronary atherosclerotic load

Eccentric Stenosis of the Carotid Artery Associated with Ipsilateral Cerebrovascular Events

“…In our study population, such arteries might account for 10% of the arteries with maximum area stenosis at 70% or more. Although the contribution of carotid calcification to cerebrovascular events is uncertain, 27,28,31,32 the present results may have been affected by the exclusion of these calcified arteries from the analysis. Second, although the present retrospective analysis demonstrated an association between stenosis geometry and pre-existent cerebrovascular events, a prospective trial is required to assess the contribution of eccentric stenosis to future cerebrovascular events.…”

“…13,[26][27][28][29][30] In a recent study on MDCT, the relationship between stroke symptoms and plaque morphology was assessed. 30 In the study, expansive carotid remodeling was greater in patients with cerebral ischemic symptoms than in asymptomatic patients, though there was no significant difference in the plaque eccentricity between symptomatic and asymptomatic patients.…”

The Impact of Expansive Arterial Remodeling on Clinical Presentation in Carotid Artery Disease: A Multidetector CT Angiography Study

“…20 Although already supplanting invasive angiography in many areas within the United States in the evaluation of stenosis, MDCT is also capable of delineating plaques on the basis of attenuation values and measuring calcium scores within the carotid arteries, which are potential markers of ischemic symptoms. 21,22 An additional new role may be the assessment of carotid wall expansion secondary to atherosclerosis with the RR. Together, these atherosclerotic plaque characteristics may lead to better risk stratification of patients with asymptomatic carotid stenosis, in whom management remains controversial.…”

Carotid Artery Stenting for Calcified Lesions

“…In most cases, we used wide fixed window settings (700-HU window, 250-HU level), though several patients required individual changes in the level and windows for optimal visualization (range, 600-1000 HU window; 150 -400 HU level). 8,9 To determine the total volume of the plaque calcification, we prepared contiguous axial source images of the index carotid lesion manifesting stenosis. The plaque calcification volume was determined by manually tracing the calcified plaque on each section for the length of the plaque; the sum of the areas of calcium multiplied by the section increment was used to determine the volume in cubic millimeters.…”

“…The plaque calcification volume was determined by manually tracing the calcified plaque on each section for the length of the plaque; the sum of the areas of calcium multiplied by the section increment was used to determine the volume in cubic millimeters. 8,9 The circumferential distribution of plaque calcifications was evaluated on axial source images at the point of maximal luminal stenosis. To determine the arc of the plaque calcification, we manually traced and measured the outside circumference of the calcification and the vessel circumference.…”