Histological verification of computerised carotid plaque characterisation (original) (raw)
Related papers
Plaque echodensity and textural features are associated with histologic carotid plaque instability
Journal of Vascular Surgery, 2016
Background: Carotid plaque echodensity and texture features predict cerebrovascular symptomatology. Our purpose was to determine the association of echodensity and textural features obtained from a digital image analysis (DIA) program with histologic features of plaque instability as well as to identify the specific morphologic characteristics of unstable plaques. Methods: Patients scheduled to undergo carotid endarterectomy were recruited and underwent carotid ultrasound imaging. DIA was performed to extract echodensity and textural features using Plaque Texture Analysis software (LifeQ Medical Ltd, Nicosia, Cyprus). Carotid plaque surgical specimens were obtained and analyzed histologically. Principal component analysis (PCA) was performed to reduce imaging variables. Logistic regression models were used to determine if PCA variables and individual imaging variables predicted histologic features of plaque instability. Results: Image analysis data from 160 patients were analyzed. Individual imaging features of plaque echolucency and homogeneity were associated with a more unstable plaque phenotype on histology. These results were independent of age, sex, and degree of carotid stenosis. PCA reduced 39 individual imaging variables to five PCA variables. PCA1 and PCA2 were significantly associated with overall plaque instability on histology (both P [ .02), whereas PCA3 did not achieve statistical significance (P [ .07). Conclusions: DIA features of carotid plaques are associated with histologic plaque instability as assessed by multiple histologic features. Importantly, unstable plaques on histology appear more echolucent and homogeneous on ultrasound imaging. These results are independent of stenosis, suggesting that image analysis may have a role in refining the selection of patients who undergo carotid endarterectomy.
Ultrasonographic Characterization of Carotid Plaques
Ultrasound in Medicine & Biology, 1998
The composition of atherosclerotic plaques in the carotid artery is assumed to be related to the development of neurological symptoms. The echo patterns produced by B-mode ultrasound may be of use in the assessment of the plaques' composition. It is suggested that fibrotic and ''stable'' plaques are more echogenic than lipid/hemorrhagic and echolucent or ''unstable'' plaques. B-mode ultrasound procedures were performed 1 day prior to surgery on 46 consecutive endarterectomies. Two observers assessed the plaques according to their echo pattern and echogenicity and sorted them into three categories: 1) predominantly echolucent, 2) heterogeneous, and 3) predominantly echogenic. The intraobserver agreement was moderate (kappa ؍ 0.44) and the interobserver agreement low (kappa ؍ 0.38). Furthermore, subjective categorization of plaque types resulted in type 1 plaques being as fibrotic as type 2 or 3 plaques. We conclude that B-mode ultrasound and subsequent subjective categorization of atherosclerotic plaques cannot adequately determine the volume of fibrosis or lipids within the plaque. © 1998 World Federation for Ultrasound in Medicine & Biology.
A new method for characterizing carotid plaque: Multiple cross-sectional view echomorphology
Journal of Vascular Surgery, 2003
Purpose: This study compares the ability of computer-derived B-mode ultrasound gray-scale measurements from a single longitudinal view (SLV) versus multiple cross-sectional views (MCSV) to differentiate symptomatic from asymptomatic carotid plaque causing more than 70% stenosis. Method: Seventy-four internal carotid artery (ICA) stenoses (70%-99%; 33 asymptomatic, 41 symptomatic within 3 months) were imaged to obtain the "best" SLV and five to eight MCSV images at 5 mm intervals from the carotid bifurcation. Digitized sonograms were computerized and normalized to the gray scale median (GSM) of blood (0) and vessel adventitia 200). Plaque GSM was determined for each frame (image analysis, MATLAB 5.3). General risk factors for stroke and plaque echogenicity (SLV GSM; minimum MCSV GSM; cross-sectional axial heterogeneity (highest minus lowest MCSV GSM) were determined for each group. Results: Risk factors for stroke were similar in both groups, as was mean SLV GSM: symptomatic, 34 (95% confidence interval [CI], 24.8-43.0), asymptomatic, 43 (CI, 32.6-53.2); P ؍ .1. Minimum MCSV GSM was lower for symptomatic plaque: 7 (CI, 4.2-9.8] vs 18.3 (CI, 12.2-24.5); P ؍ .002. Greater axial GSM heterogeneity was present in symptomatic plaque: 34.5 (CI, 27.2-41.9) vs 16 (CI, 11.0-20.8); P ؍ .0001. Conclusions: MCSV cross-sectional imaging that enables objective assessment of regional plaque echolucency and heterogeneity is more sensitive than SLV sonography for differentiating symptomatic from asymptomatic plaque. (J Vasc Surg 2003;37:778-84.) From the General Infirmary at Leeds. Competition of interest: none.
European Journal of Vascular and Endovascular Surgery, 1995
Objective: To correlate B-mode ultrasound findings to carotid plaque histology. Design: European multicentre study (nine centres). Material and Methods: Clinical presentation and risk factors were recorded and preoperative ultrasound Duplex scanning with special emphasis on B-mode imaging studies was performed in 270 patients undergoing carotid endarterectomy. Perioperatively, macroscopic plaque features were evaluated and the removed specimens were analysed histologically for fibrous tissue, calcification and 'soft tissue" (primarily haemorrhage and lipid). Results: Males had more soft tissue than females (p = 0.0006), hypertensive patients less soft tissue than normotensive (p = 0.01) and patients with recent symptoms more soft tissue than patients with earlier symptoms (p = 0.004). There was no correlation between surface description on ultrasound images compared to the surface judged intraoperatively by the surgeon. Echogenicity on B-mode images was inversely related to soft tissue (p = 0.005) and calcification was directly related to echogenicity (p < 0.0001). Heterogeneous plaques contained more calcification than homogeneous (p = 0.003), however, there was no difference in content of soft tissue. Conclusion: Ultrasound B-mode characteristics are related to the histological composition of carotid artery plaques and to patient's history. These results may imply that patients with distant symptoms may be regarded and treated as asymptomatic patients whereas asymptomatic patients with echolucent plaques should be considered for carotid endarterectomy.
Plaque Echodensity and Textural Features Are Associated With Carotid Plaque Instability
Journal of Vascular Surgery, 2015
Background: Carotid plaque echodensity and texture features predict cerebrovascular symptomatology. Our purpose was to determine the association of echodensity and textural features obtained from a digital image analysis (DIA) program with histologic features of plaque instability as well as to identify the specific morphologic characteristics of unstable plaques. Methods: Patients scheduled to undergo carotid endarterectomy were recruited and underwent carotid ultrasound imaging. DIA was performed to extract echodensity and textural features using Plaque Texture Analysis software (LifeQ Medical Ltd, Nicosia, Cyprus). Carotid plaque surgical specimens were obtained and analyzed histologically. Principal component analysis (PCA) was performed to reduce imaging variables. Logistic regression models were used to determine if PCA variables and individual imaging variables predicted histologic features of plaque instability. Results: Image analysis data from 160 patients were analyzed. Individual imaging features of plaque echolucency and homogeneity were associated with a more unstable plaque phenotype on histology. These results were independent of age, sex, and degree of carotid stenosis. PCA reduced 39 individual imaging variables to five PCA variables. PCA1 and PCA2 were significantly associated with overall plaque instability on histology (both P [ .02), whereas PCA3 did not achieve statistical significance (P [ .07). Conclusions: DIA features of carotid plaques are associated with histologic plaque instability as assessed by multiple histologic features. Importantly, unstable plaques on histology appear more echolucent and homogeneous on ultrasound imaging. These results are independent of stenosis, suggesting that image analysis may have a role in refining the selection of patients who undergo carotid endarterectomy.
Ultrasonic carotid plaque morphology
The main criterion currently used to assess stroke risk due to atheroma of the carotid bifurcation is the degree of stenosis. Although the benefit of carotid endarterectomy in stroke prevention has been demonstrated by prospective randomised trials, this benefit is moderate. Other risk factors have been suggested, such as ultrasonic carotid plaque characterisation, which may help in the identification of a high risk subgroup which will derive the maximum benefit from carotid endarterectomy. This paper reviews the literature on the clinical importance of carotid plaque characterization on histopathological and ultrasonographic grounds, and underlines the potential of objective quantitative assessment of carotid plaque echodensity in the identification of a high risk group for stroke.
Journal for Vascular Ultrasound, 2010
Introduction Better methods are needed to determine the course of intervention in patients with atherosclerosis; therefore, plaque characterization is increasing in importance. Current guidelines suggest that the degree of stenosis and symptoms are the only criteria for the selection of the surgical intervention. However, there remain some challenges. The characterization of plaque morphology may help determine the best course of therapy. Magnetic resonance imaging and computed tomography are current standard techniques to evaluate plaque morphology, but they are expensive and unsuitable for long term surveillance and monitoring. Objective In this research, an ultrasound-based methodology for the characterization of carotid plaques is shown. This technique requires the injection of a small volume (approximately 1.5 mL) of contrast agent and the acquisition of postcontrast images. The rationale of this technique is that poorly perfused tissues (such as lipids) show a lower contrast e...
Annals of Vascular Surgery, 2020
Background: The aim of this study is to investigate the correlation of clinical and ultrasound parameters with characters of vulnerable atherosclerotic carotid plaque, as evaluated at preoperative magnetic resonance angiography (MRA), in patients submitted to carotid endarterectomy (CEA), in order to develop a clinical risk score for plaque vulnerability. Methods: Preoperative data of patients submitted to CEA for significant carotid stenosis from January 1, 2012 to December 31, 2016 were retrospectively collected. The available case series was randomly divided into 2 groups, including a training (60%) and a validation series (40%). Data of plaque vulnerability were assessed at preoperative MRA scans. Univariate analysis was used on the training series to correlate the preoperative covariates available to the features of plaque vulnerability. Therefore, a backward selection procedure was performed again on the training series and on the validation series to assess if the same variables were associated to data of plaque vulnerability, in order to obtain a prediction model for the risk of plaque vulnerability. Odds ratios (ORs) with 95% confidence intervals were reported. P values <0.05 were considered statistically significant. Results: The training case series consisted of 352 patients, while the validation case series of 248 patients. After univariate analysis and logistic regression, on the training and the validation series respectively, 6 variables were significantly associated to features of vulnerable plaque at preoperative MRA. These included male sex (OR 2.05), diabetes mellitus (OR 3.06), coronary artery disease (OR 1.95), neutrophil/lymphocyte ratio (OR 17.99), platelet counts (OR 1.03), and gray-scale median value (OR 0.84). A nomogram was then obtained from the final logistic model, in order to predict the probability of the presence of vulnerable carotid plaque, using a weighted points system. This risk score was then applied to the validation series. The validation data were found to have a C-index of 0.934.
Carotid plaque typing by multiple-parameter ultrasonic tissue characterization
Ultrasound in Medicine & Biology, 1997
We evaluated the ability of ultrasonic tissue characterization (UTC), based on backscattered echo signals, to distinguish among the components of advanced carotid plaques. We performed spectral analysis of echo signals acquired from human carotid endarterectomy specimens in vitro to calculate three parameters of the calibrated power spectrum: slope, intercept and total power for fibrous, lipid pool and thromhus constituents of plaque. Plaque constituents were identified histologically. We evaluated classification efficacy by discriminant function analysis. Slope and intercept parameters alone provided correct classification in 92.5%, 57.6% and 72.4% of fibrous, lipid pool and thrombus plaque components, respectively. Slope, intercept and total power used in combination improved classification of the three tissue types to 93.0%, 69.7% and 81.0%. The overall proportion of correctly classified tissue regions increased from 84.5% to 88.0% by the combined use of the three parameters. The improvement in classification that occurred when we included total power as a third parameter suggests that ultrasound plaque components may not consist solely of small, randomly distributed isotropic scatterers. Our ability to identHy plaque thrombi provides motivation for future studies of parameter-based imaging methods for identifflug such plaque that presents an increased risk of embolic neurologic ischemic events.