Carotid Plaque Surface Irregularity Research Articles

Contrast-Enhanced Ultrasound Feasibility in Assessing Carotid Plaque Vulnerability-Narrative Review.

The risk assessment for carotid atherosclerotic lesions involves not only determining the degree of stenosis but also plaque morphology and its composition. Recently, carotid contrast-enhanced ultrasound (CEUS) has gained importance for evaluating vulnerable plaques. This review explores CEUS's utility in detecting carotid plaque surface irregularities and ulcerations as well as intraplaque neovascularization and its alignment with histology. Initial indications suggest that CEUS might have the potential to anticipate cerebrovascular incidents. Nevertheless, there is a need for extensive, multicenter prospective studies that explore the relationships between CEUS observations and patient clinical outcomes in cases of carotid atherosclerotic disease.

Quantitative assessment of carotid plaque surface irregularities and correlation to cerebrovascular symptoms

BackgroundThe purpose of this study was to determine whether surface irregularities measured from ultrasound images of carotid artery plaques and quantified using a novel method, correlate with the presence of ipsilateral hemispheric cerebrovascular symptoms.MethodsA plaque surface irregularity index (SII) was measured in 47 carotid artery plaques (32 subjects, stenosis range 10% -95%, 49% symptomatic) using ultrasound image sequences spanning several cardiac cycles. The differences in the distribution of SII in plaques with ipsilateral hemispheric symptoms versus those without symptoms and the correlation between the SII of plaques and the degrees of stenosis of the corresponding arteries were assessed. Diagnostic performance of plaque SII was evaluated on its own and in combination with the degree of stenosis.ResultsThe mean SII was significantly greater for plaques with ipsilateral hemispheric symptoms (1.89 radians/mm) than for asymptomatic plaques (1.67 radians/mm, p = 0.03). There was no statistically significant association between the SII and the degree of stenosis (p = 0.30). SII predicted the presence of cerebrovascular symptoms with an accuracy of 66% (sensitivity 65%, specificity 67%) on its own and with an accuracy of 83% (sensitivity 96%, specificity 71%) in combination with the degree of stenosis.ConclusionsQuantitative assessment of carotid plaque surface irregularities using a novel SII parameter correlates with the presence ipsilateral hemispheric cerebrovascular symptoms and may increase diagnostic performance beyond that provided by the degree of stenosis.

頚動脈ステント留置術後のステント外残存潰瘍（Residual Ulceration）に関する研究

Object: Carotid ulceration plaque is a high risk factor for stroke and vascular events. We studied residual ulceration (RU) after carotid artery stenting (CAS). Material and methods: A total of 65 CAS procedures were performed at our institute between January 2007 and November 2010. This study included 65 successful CAS procedures in 56 patients (51 men and five women) with a mean age of 76.6 years. Results: Residual ulceration was found in nine lesions (eight patients). One of nine cases showed transient weakness of the right upper extremity six hours after CAS and confirmed HITS by TCD, apparently caused by an embolus from residual ulceration. None of the other eight patients experienced an ischemic event due to RU. Follow-up computed tomography angiograms after CAS performed in all cases revealed that RU disappeared. Discussion and conclusion: There are many reports that the possibility that RU causes post-operative embolism is low. Ischemic stroke might be expected due to RU because carotid plaque surface irregularity is considered to be one of the risk factors for microembolism through the stent mesh. We conclude that RU after the CAS improves spontaneously but is a risk factor for cerebral embolism.

Coronary artery calcium is associated with degree of stenosis and surface irregularity of carotid artery

ObjectivesCarotid stenosis and plaque stability are critical determinants of risk for ischemic stroke. The aim of this study is to elucidate the association of CAC with carotid stenosis and plaque characteristics. MethodsWe examined data from the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective cohort study of subclinical cardiovascular disease in multiethnic participants (N = 6814). The association between CAC measured by computed tomography and carotid ultrasonography of carotid plaque was examined using multiple logistic linear models adjusting for traditional vascular risk factors including ethnicity. We also developed ethnic specific models to compare the relationship between CAC and carotid disease across the four ethnicities. ResultsSignificant carotid stenosis was associated with the presence of CAC (OR 1.73; 95% CI, 1.20–2.49) and log-transformed Agatston score (OR per 1 point increase, 1.18; 95% CI 1.04–1.35). Overt carotid stenosis was also associated with the presence of CAC (OR, 2.34; 95% CI, 1.93–2.83) and log-transformed Agatston score (OR per 1 point increase, 1.53; 95% CI 1.38–1.69). Irregular plaque surface was associated with the presence of CAC (OR, 1.87; 95% CI 1.50–2.32) and the log-transformed Agatston score (OR per 1 point 1 increase, 1.31; 95% CI 1.16–1.48). Associations between CAC and stenosis/stability were not different across ethnicities. ConclusionsBoth the presence of CAC and log-transferred Agatston score are independently associated with significant/overt carotid stenosis and carotid plaque surface irregularity regardless of ethnicity. The subjects with a positive or increased CAC score are more likely to have carotid disease potentially increasing their risk for future ischemic stroke.

Carotid Plaque Surface Irregularity Predicts Cerebral Embolism during Carotid Artery Stenting

Background and Purpose: Carotid artery stenting (CAS) is associated with the risk of periprocedural embolic events. The procedural risk may vary with plaque characteristics. We aimed at determining the impact of carotid plaque surface irregularity on the risk of cerebral embolism during CAS. Methods: Solid microembolic signals (MES) during CAS for symptomatic carotid stenosis were assessed by means of dual-frequency transcranial Doppler ultrasound. Study endpoint was the number of solid MES during CAS in 12 patients with irregular carotid stenosis compared to 12 matched patients with smooth carotid stenosis. Results: A total of 438 solid MES were detected. The cumulative number of solid MES was 329 in patients with irregular plaques and 109 in those with smooth plaques. The proportion of subjects in whom solid MES were detected was higher in the irregular plaque group (11/12) than in the smooth plaque group (5/12) (p = 0.030). The numbers of solid MES per CAS procedure and per hour of CAS procedure were both higher in patients with irregular plaques than in those with smooth plaques (p = 0.008 and 0.015, respectively). Conclusions: Carotid plaque surface irregularity predicts solid cerebral embolism during stenting of symptomatic carotid artery stenosis.

A surprise behind the dark

Standard ultrasound has a poor accuracy in the detection of carotid plaque surface irregularities and ulcers, which are features of vulnerable lesions. Sonographic contrast agents can improve vessel wall lumen definition, thus potentially overcoming this limitation. Recent studies also suggest that contrast ultrasound can be used to study intraplaque neovascularizaion, a potential marker of high-risk lesions. This case represents a striking example of the added value of contrast ultrasound to improve diagnostic accuracy of vascular studies, particularly in the detection of plaque surface irregularities and plaque neovascularization.

Analysis of carotid lumen surface morphology using three-dimensional ultrasound imaging

Carotid plaque surface irregularity and ulcerations play an important role in the risk of ischemic stroke. Ulcerated or fissured plaque, characterized by irregular surface morphology, exposes thrombogenic materials to the bloodstream, possibly leading to life- or brain-threatening thrombosis and embolization. Therefore, the quantification of plaque surface irregularity is important to identify high-risk plaques that would likely lead to vascular events. Although a number of studies have characterized plaque surface irregularity using subjective classification schemes with two or more categories, only a few have quantified surface irregularity using an objective and continuous quantity, such as Gaussian or mean curvature. In this work, our goal was to use both Gaussian and mean curvatures for identifying ulcers from 3D carotid ultrasound (US) images of human subjects. Before performing experiments using patient data, we verified the numerical accuracy of the surface curvature computation method using discrete spheres and tori with different sampling intervals. We also showed that three ulcers of the vascular phantom with 2 mm, 3 mm and 4 mm diameters were associated with high Gaussian and mean curvatures, and thus, were easily detected. Finally, we demonstrated the application of the proposed method for detecting ulcers on luminal surfaces, which were segmented from the 3D US images acquired for two human subjects.

Abstract 957: Elevated Levels of Neopterin are Associated with Carotid Complex Plaques in Patients with Stable Angina Pectoris

Background: Neopterin is produced by activated macrophages and serves as an activation marker for monocytes/macrophages. Serum levels of neopterin have been shown to be associated with the presence of complex coronary lesions in unstable angina pectoris. However, the relationship between neopterin levels and complex carotid lesions is still unknown. We investigated the association between plasma neopterin levels and the characteristics of carotid plaques in patients with stable angina pectoris (SAP). Moreover, we immunohistochemically studied the presence of neopterin in carotid endarterectomy specimens. Methods: We studied 65 SAP patients who were scheduled coronary angiography. In all patients, plasma neopterin levels were measured and carotid ultrasound was performed for evaluation of carotid artery plaque score (PS) defined by the sum of plaque thickness, plaque number (PN) and plaque surface irregularity. Frozen tissue of 40 endarterectomy specimens for extracranial high-grade carotid stenosis were immunohistochemically examed with antibodies against macrophages and neopterin. Results: There was no significant correlation between plasma neopterin levels and PS (P=0.38) or PN (P=0.49). On the other hand, plasma neopterin levels were significantly higher in patients with carotid plaque surface irregularity compared with patients without it (25.4 ± 13.5 nmol/L vs.16.9 ± 6.5 nmol/L, P=0.0015). Carotid plaque irregularity was detected more frequently in patients with higher neopterin levels (>=18.5 nmol/L median) compared with those with lower neopterin levels (41.9% vs. 16.1%, P=0.025). Using multivariate analyses, nepopterin levels (OR, 1.11; 95%CI, 1.01 to 1.21; P=0.023) and the number of diseased coronary vessels (OR, 2.51; 95%CI, 1.01 to 6.22; P=0.047) are independently associated with carotid plaque irregularity. Immunohistochemical staining showed abundant neopterin-positive macrophages in the unstable carotid plaques. Conclusions: Neopterin levels are associated with carotid complex plaques rather than the severity of carotid atherosclerotic change. Neopterin can be considered as one of the significant markers of plaque destabilization in not only coronary artery but carotid artery atherosclerotic lesions.

Beyond Percent Stenosis: Carotid Plaque Surface Irregularity and Risk of Stroke

Beyond Percent Stenosis: Carotid Plaque Surface Irregularity and Risk of Stroke

Carotid plaque surface irregularities increase risk of ischemic stroke

Carotid plaque surface irregularities increase risk of ischemic stroke

Carotid plaque surface irregularities increase risk of ischemic stroke

Carotid plaque surface irregularities increase risk of ischemic stroke

Major carotid plaque surface irregularities correlate with neurologic symptoms

Purpose: Many studies have linked carotid plaque surface irregularities with stroke risk, but this relationship has been obscured by the limited ability of available imaging modalities to resolve plaque surface morphology. To address this issue, we performed a prospective study correlating the presenting neurologic symptoms of patients with high-resolution magnetic resonance imaging (MRI; 200 μm) studies of ipsilateral plaque surface invaginations and ledges, lumen shape, and the location of the plaque bulk creating the stenosis. Methods: One hundred patients, 17 women and 83 men, 45 to 81 years old (mean, 68 years) underwent surgery. Forty-five patients had a transient ischemic attack (TIA) or stroke as the indication for surgery, and 55 patients had no symptoms. Angiograms were obtained in 50 patients. Carotid plaques were removed “en bloc” and placed in gadolinium doped saline for imaging in a Siemens Symphony, 1.5T scanner with a custom-built transmit-receive radiofrequency coil. The resulting slice thickness was 200 μm, with 200 μm by 200 μm in plane resolution. The MRI data and angiograms were reviewed by using National Institutes of Health Image software and read by consensus. A surface irregularity was categorized as a ledge or ulcer and measured by using electronic calipers. Luminal shape was determined at the point of maximal stenosis with a “slice” set at 90° to the lumen axis. The location of the maximal stenosis was recorded. In the internal carotid artery, plaque bulk was designated to be on the flow divider wall or non-flow divider wall. Results: The mean maximal stenosis was 81.5% ± 12.0%. Surface contour irregularities were found in 80 plaques. Thirty-five plaques were graded as having major surface contour irregularities, and 45 plaques were graded as having minor irregularities. There was a significant correlation between major surface irregularity and TIA or stroke (P <.01). Irregular plaques were identified with angiography, but the irregularity in size was underestimated (P <.01). Only 28% of plaques had circular lumens; 50% had elliptical lumens, and 22% had either crescentic or multi-lobular lumens. The maximal stenosis was located in the internal carotid artery in 82 plaques, the bifurcation in 17 plaques, and the common carotid artery in one plaque. Conclusion: Surface irregularities were revealed by means of submillimeter resolution of the carotid plaques with MRI to be common, but only the presence of major irregularities correlated with the patient having TIA or stroke. Lumen shape and plaque location did not appear to predict stroke risk, but may effect imaging accuracy in determining the degree of stenosis. These data further define the relationship of plaque irregularity and cerebrovascular symptoms caused by atheroemboli. (J Vasc Surg 2002;35:741-7.)