Carotid Plaque Imaging Research Articles

Lipid-related radiomics of low-echo carotid plaques is associated with diabetic stroke and non-diabetic coronary heart disease.

Carotid plaque radiomics-included models have increased the predictive capacity of cardiovascular risk, but the radiomic features of these models were inconsistent in previous studies. Lipids could be used to select the most important radiomic feature. A retrospective case‒control study was performed in 153 diabetic and 76 non-diabetic patients with carotid plaque detected by ultrasound. Cerebro-cardiovascular disease (CCD), comprising coronary heart disease (CHD) and stroke, was the primary outcome. Clinical variables and radiomic features of longitudinal carotid plaque images were collected. Principal component analyses were used to compare the power of radiomic and lipid features in discrimination between diabetes, CCD patients, and their opposites. Partial least square regression, logistic regression analyses, and least absolute shrinkage and selection operator (LASSO) regression were performed for high-risk radiomic features. The diagnostic capacity of the models was evaluated. PCA based on radiomics or lipids did not show good discrimination of diabetes, CCD, and their opposites. There were 6 overlapping radiomic features associated with lipid profiles, but only original_firstorder_Mean was negatively associated with diabetic stroke [adjusted OR = 0.468 (0.243-0.902), P = 0.023] and nondiabetic CHD [adjusted OR = 0.311 (0.123-0.783), P = 0.013]. The associations remained independent in the LASSO regression models (β=-0.032 for diabetic stroke, and - 0.026 for non-diabetic CHD). The diagnostic capacity of lipid-related radiomics for diabetic stroke (0.556 to 0.688) and non-diabetic CHD (0.690 to 0.783) was increased by the combination of these clinical variables. Carotid plaque radiomics is associated with lipids and stroke in diabetes, and quantitative features are useful for therapeutic guidance and cardiovascular risk evaluation in clinical use.

Prediction of cardiovascular events after carotid endarterectomy using pathological images and clinical data.

Carotid endarterectomy (CEA) is a surgical treatment for carotid artery stenosis. After CEA, some patients experience cardiovascular events (myocardial infarction, stroke, etc.); however, the prognostic factor has yet to be revealed. Therefore, this study explores the predictive factors in pathological images and predicts cardiovascular events within one year after CEA using pathological images of carotid plaques and patients' clinical data. This paper proposes a two-step method to predict the prognosis of CEA patients. The proposed method first computes the pathological risk score using an anomaly detection model trained using pathological images of patients without cardiovascular events. By concatenating the obtained image-based risk score with a patient's clinical data, a statistical machine learning-based classifier predicts the patient's prognosis. We evaluate the proposed method on a dataset containing 120 patients without cardiovascular events and 21 patients with events. The combination of autoencoder as the anomaly detection model and XGBoost as the classification model obtained the best results: area under the receiver operating characteristic curve, accuracy, sensitivity, specificity, and F1-score were 81.9%, 84.1%, 79.1%, 86.3%, and 76.6%, respectively. These values were superior to those obtained using pathological images or clinical data alone. We showed the feasibility of predicting CEA patient's long-term prognosis using pathological images and clinical data. Our results revealed some histopathological features related to cardiovascular events: plaque hemorrhage (thrombus), lymphocytic infiltration, and hemosiderin deposition, which will contribute to developing preventive treatment methods for plaque development and progression.

The evolution of carotid atherosclerotic plaque composition: a prospective study

Abstract Background The rupture of carotid atherosclerotic plaque is one of the major causes of ischemic stroke, and largely determined by the composition of the plaque. To date, most studies on carotid plaque composition focused on individual plaque components, whilst the interplay between different components within the same plaque may be a critical driving force for plaque evolution and rupture. Objectives To determine the interplay between carotid plaque components over time and describe the dynamics of plaque composition with a specific focus on age- and sex-specific changes in a population-based setting. Methods From a population-based cohort in Netherlands, 802 participants (mean age ± SD 68 ± 8 years, 43% women) with subclinical carotid atherosclerosis underwent repeat magnetic resonance imaging (MRI) of carotid plaque (first scan between 2007 and 2012, second scan between 2014 to 2017). We evaluated carotid plaque composition, including calcification, lipid-rich necrotic core (LRNC) and intraplaque hemorrhage (IPH). To assess the relationship between the incidence of one specific component and baseline plaque composition, plaques with this specific component present at the baseline were excluded. Generalized estimation equation models were used with adjustments for baseline plaque size and cardiovascular risk factors. We demonstrated the evolution of plaque composition along age and by sex. Results Baseline presence of calcification in carotid plaque is independently associated with a higher incidence of IPH (adjusted odds ratio: 2.25; 95% confidence interval: 1.40 to 3.63). No associations were found between baseline plaque composition and the new onset of calcification or LRNC. The proportion of complex plaques with multiple components significantly increased at follow-up (Figure 1a). The plaque composition dramatically evolved over time and the proportion of plaques with two or more components started with 10% around 55 years and increased to over 50% after 70 years of age (Figure 1b). Although the age distribution was comparable between men and women, men were more likely to have and develop plaques with multiple vulnerable plaque components such as IPH (Figure 2). Conclusions A higher incidence of IPH was found in plaques with baseline calcification. The pre-existing plaque composition strongly determines how the plaque will evolve over time. Given the interplay between individual components, the overall plaque composition exhibits significant age- and sex- specific characteristics.

C-C motif chemokine ligand 3 is associated with atherosclerotic plaque vulnerability and increased risk of mortality

Abstract Background and Purpose Chemokines play a crucial role in the inflammatory process underlying atherosclerotic plaque formation, progression and subsequent cardiovascular events. However, the specific role of C-C motif chemokine ligand 3 (CCL3) in atherosclerosis remains largely unexplored. This study aims to explore associations between intra-plaque levels of CCL3 and plaque vulnerability as well as to investigate the prognostic role of circulating CCL3 levels in patients undergoing carotid endarterectomy. Methods The CCL3 protein expression was measured using a proximity extension assay in 207 human carotid plaques and 558 plasma samples from patients undergoing carotid endarterectomy, all enrolled in the Carotid Plaque Imaging Project (CPIP) cohort. Protein expression is quantified as normalized protein expression (NPX), an arbitrary unit on a log2-scale. Plaque components and extracellular matrix including smooth muscle cells, macrophages, neutral lipids, intraplaque hemorrhage, collagen (by histology), and matrix metalloproteinases (assessed biochemically), were quantified. Plaque vulnerability index was calculated as the sum percentage of plaque areas stained for lipids, macrophages and hemorrhage, divided by the sum percentage of smooth muscle cells and collagen. Patients were followed up to 10.2 years to record cardiovascular events and mortality. Results Plaque and circulating levels of CCL3 were higher in symptomatic patients compared to asymptomatic patients (plaque, median NPX (interquartile range, IQR): 18.2 (17.4–19.1) vs 17.2 (16.4–18.0), P<0.001; plasma, median NPX (IQR): 1.78 (1.42–2.21) vs 1.56 (1.28–1.97), P<0.001). Plaque levels of CCL3 showed positive correlations with neutral lipids, macrophages, intraplaque hemorrhage, plaque vulnerability index and matrix metalloproteinases including MMP1, MMP2, MMP9, MMP10 and TIMP1, but inversely with smooth muscle cells. Among 511 patients with complete follow-up and circulating CCL3 measures, 144 (28.2%) patients developed cardiovascular events and 123 (24.1%) patients died. Elevated circulating CCL3 levels were associated with increased risk of cardiovascular events (hazard ratio (HR) per standard deviation (SD) = 1.40, 95% CI 1.06–1.84) and mortality (HR per SD=1.77, 95% CI 1.34–2.33), respectively. Higher levels of circulating CCL3 remained independently associated with an increased risk of mortality (HR per SD=1.50, 95% CI 1.09–2.04) even after adjustment for potential confounders. Conclusions Plaque levels of CCL3 are associated with plaque vulnerability features. Circulating levels of CCL3 predict higher risk of cardiovascular events and mortality among carotid endarterectomy patients.

An Unsupervised Learning Tool for Plaque Tissue Characterization in Histopathological Images.

Stroke is the second leading cause of death and a major cause of disability around the world, and the development of atherosclerotic plaques in the carotid arteries is generally considered the leading cause of severe cerebrovascular events. In recent years, new reports have reinforced the role of an accurate histopathological analysis of carotid plaques to perform the stratification of affected patients and proceed to the correct prevention of complications. This work proposes applying an unsupervised learning approach to analyze complex whole-slide images (WSIs) of atherosclerotic carotid plaques to allow a simple and fast examination of their most relevant features. All the code developed for the present analysis is freely available. The proposed method offers qualitative and quantitative tools to assist pathologists in examining the complexity of whole-slide images of carotid atherosclerotic plaques more effectively. Nevertheless, future studies using supervised methods should provide evidence of the correspondence between the clusters estimated using the proposed textural-based approach and the regions manually annotated by expert pathologists.

Diagnostic accuracy of carotid plaque magnetic resonance imaging compared to histopathology in symptomatic carotid artery stenosis

IntroductionVulnerable plaques have been shown to predict ipsilateral cerebral ischemic events and identifying them leads to appropriate secondary stroke prevention strategies. We evaluated the diagnostic accuracy of MR carotid plaque imaging in identifying plaque vulnerability when compared with histopathological findings in patients with symptomatic carotid stenosis who underwent carotid endarterectomy (CEA). MethodsA prospective cohort of forty-five consecutive patients with moderate to severe symptomatic carotid stenosis who underwent CEA at a tertiary Indian hospital had 3 T MRI plaque imaging with multi-parametric protocol between November 2021 and December 2022. Images were analyzed by a vascular radiologist blinded to histopathological data. High-risk plaque characteristics such as lipid rich necrotic core (LRNC), intraplaque hemorrhage (IPH), thin fibrous cap and ulceration were assessed and correlated with histopathological findings as per American Heart Association (AHA) classification using Cohen’s kappa statistics to obtain diagnostic accuracies. ResultsOf the 45 patients, 38(84 %) were males. The mean age was 65 ± 7.7 years and mean duration to CEA from the most recent event was 57 days (57 ± 46 days). A significant correlation between MR plaque imaging and histopathology was noted for IPH (sensitivity-91 %, specificity-86 %, κ = 0.774, p < 0.001), LRNC (sensitivity-92.1 %, specificity-85.7 %, κ = 0.697, p < 0.001), and plaque ulceration (sensitivity-84.6 %, specificity-78.1 %, κ = 0.563, p < 0.001). MRI had an overall sensitivity and specificity of 92.3 % and 84.2 % respectively (κ = 0.77, p < 0.001) in discriminating high risk plaques. ConclusionMR plaque imaging shows a very good correlation with histopathology and can identify unstable high-risk plaques with high accuracy. This may have implication in selection of patients for carotid revascularization in symptomatic carotid stenosis.

Circulating LIGHT/TNFSF14 levels are negatively associated with cardiovascular mortality, while intra-plaque levels are associated with symptomatic cerebrovascular disease

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Swedish Heart and Lung Foundation, Åke Wiberg's Foundation Background Plaque rupture is the underlying cause of most cardiovascular events, such as stroke and myocardial infarction. Co-stimulatory molecules, the immune checkpoints, are emerging as strong candidates to battle atherosclerosis progression. The co-stimulatory molecule LIGHT (tumour necrosis factor 14; TNFSF14) exists in foam cell-rich regions of atherosclerotic plaques, but whether it is associated with a high-risk plaque phenotype and cardiovascular events is not known. Purpose This study investigates the association between intra-plaque and circulating LIGHT levels and cardiovascular disease. Method Plaque levels of LIGHT/TNFSF14 were measured in plasma and homogenised carotid endarterectomy plaques by Proximity Extension Assay in subjects from the Carotid Plaque Imaging Cohort (CPIP; N=557 and 201, respectively). Homogenates were further examined by multi-plex cytokine analysis and ELISA, and tissue plaque sections through immunohistochemistry. Multivariate Cox proportional hazards analysis was performed on normalized (logarithmically transformed) values. Results Plaque, but not circulating, levels of LIGHT were associated with the occurrence of pre-operative cerebrovascular symptoms (p=0.00014). Furthermore, intra-plaque levels of LIGHT correlated strongly with the histological plaque vulnerability index (p=5x10-15): a ratio between the sum of destabilising versus stabilising plaque components (i.e. macrophages, intra-plaque haemorrhage and lipids versus smooth muscle cells and collagen) as well as with necrotic core size and the inflammatory cytokines interleukin(IL)-1β, IL-6, chemokine (C-C motif) ligand (CCL)-2, CCL4 and CCL5. Moreover, plaque LIGHT levels correlated with several components of the extracellular matrix turnover machinery, including cleaved collagen, fibromodulin, ADAMTS7 (a disintegrin and metalloproteinase with thrombospondin motifs-7) and matrix metalloproteinases 1, 2, 9 and 10. While plaque LIGHT levels were not predictive of cardiovascular death, circulating LIGHT levels were negatively associated with risk of cardiovascular death (after 6 ½ years) after correcting for the possible confounders age, sex, cerebrovascular symptoms, diabetes, high-sensitivity C-reactive protein, inflammatory disease, hypertension and smoking (hazard ratio=0.032, confidence interval=0.420-0.951, p=0.028). Conclusion Though intra-plaque LIGHT levels are associated with a rupture-prone plaque phenotype and pre-operative symptoms, circulating levels are associated with a lower risk of future cardiovascular mortality. This suggest that upregulation of LIGHT in atherosclerotic plaques may occur as part of a reparative rupture response and, systemically, reflect efficient wound-healing capacity.

Asporin expression is associated with human atherosclerotic plaque integrity

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): This work was supported by the Swedish Research Council, the Swedish Heart and Lung Foundation, Skåne University Hospital funds Background Calcification serves as a clinical marker of atherosclerotic plaque burden. Recent studies have also shed light on its intricate association with plaque vulnerability, likely depend on calcification structures and the surrounding environment. Asporin (ASPN) is a member of the small-leucine-rich proteoglycans that contains a unique and well-conserved stretch of aspartate (D) residues, which mimic the role of glycosaminoglycans. Via its D-repeat, ASPN can interact with calcium and several other extracellular matrix molecules, thus influencing collagen mineralization and TGF-β signaling. ASPN expression has been shown to be higher in asymptomatic compared to symptomatic atherosclerotic plaques, suggesting a potential protective role. However, the role of ASPN in maintaining plaque integrity remains unknown. Purpose Here we aimed to explore the role of ASPN in atherosclerosis, by investigating if ASPN was expressed in human carotid plaques and by determining if ASPN is associated with risk for postoperative cardiovascular events and death. Methods ASPN and TGF-β protein levels were measured by ELISA and Milliplex in 176 human plaque tissue homogenates obtained from the Carotid Plaque Imaging Project (CPIP) biobank. Plaque tissue sections were stained for ASPN, destabilizing (CD68, oil red O, glycophorin A) and stabilizing plaque components (Movat, α-actin). Plaque tissue RNA expression levels were assessed in 82 plaques using bulk RNA sequencing. Plaque levels of phosphate, elastin and collagen were measured using ELISA. Results ASPN protein levels were higher in plaques from asymptomatic patients compared to symptomatic patients (p=0.011). ASPN RNA levels correlated positively to RNA levels of the smooth muscle cell markers ACTA2, MYH11 and TAGLN. Moreover, protein levels correlated with plaque levels of phosphate (r=0.258, p=0.001), elastin (r=0.423, p&amp;lt;0.001), collagen (r=0.248, p=0.002) and stability factors like the TGF-β family members, TGF-β1 (r=0.176, p=0.035), TGF-β2 (r=0.581, p&amp;lt;0.001) and TGF-β3 (r=0.396, p&amp;lt;0.001). Furthermore, plaque ASPN protein concentration, correlated inversely with a histological plaque vulnerability index (r=-0.265, p=0.0029), which is ratio between the plaque area of destabilizing (macrophages, lipids, intra-plaque hemorrhage) and stabilizing plaque components (collagen and smooth muscle cells). Additionally, above median ASPN levels were associated with lower risk for postoperative cardiovascular events (p=0.008) and death (p=0.009). Conclusion Our findings suggest that elevated levels of ASPN might have a crucial role in maintaining plaque stability, affecting plaque calcification.

The extracellular matrix proteoglycan serglycin is associated with human atherosclerotic plaque inflammation

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): This work was supported by grants from the Swedish Research Council, the Swedish Heart and Lung Foundation, Skåne University Hospital funds, Royal Physiographic Society in Lund and O.E. and Edla Johanssons Foundation. Background Atherosclerotic cardiovascular disease is caused by the formation of plaques in the arterial wall which contain lipids, cells, cell debris and a unique extracellular matrix (ECM) signature. These plaques may ultimately rupture or erode away causing thrombosis, thereby leading to myocardial infarction or stroke. Rupture-prone plaques generally bear a greater inflammatory activity, with ECM proteins suggested to influence the inflammatory activity. Among many ECM proteins, serglycin (SRGN) is highly expressed by inflammatory cells, and SRGN has been linked to modulation of the inflammatory response in disease such as cancer. Yet, if SRGN contributes to the inflammatory circuitry in human atherosclerotic plaques remains to be explored. Purpose We aimed to investigate if SRGN was associated with inflammation in atherosclerotic plaques. Methods Plaque protein levels of SRGN were measured by ELISA in human carotid plaques obtained from the Carotid Plaque Imaging Project (CPIP) biobank. Plaque RNA expression levels of SRGN and cell markers were assessed by plaque bulk RNA sequencing. SRGN expression and distribution were further examined in tissue plaque sections through histology and multispectral imaging. In vitro models were used to investigate the functional consequences of SRGN expression changes, using SRGN CRISPR knockout THP1 monocytic cells. Immunoprecipitation of SRGN and immunoblotting against SRGN, heparan and chondroitin sulfate chains were employed to structurally characterize plaque protein SRGN. Results SRGN protein levels were significantly higher in plaques from asymptomatic patients compared to symptomatic. Multispectral imaging showed that SRGN protein was observed in plaque areas rich in macrophages and lipids. Using immunoprecipitation and immunoblotting, we identified a unique low glycosylated plaque SRGN, with both heparan sulfate and chondroitin sulfate glycosaminoglycans decorating its protein core. This exclusive configuration suggests that the plaque cell origin of SRGN may be macrophages or mast cells. In support of this, plaque SRGN RNA expression correlated with RNA levels of pro-inflammatory macrophage cells markers like CD68, CD163, MRC1, ITGAX. Plaque SRGN protein levels correlated with plaque levels of oxidised lipoproteins, proatherogenic (CCL1, IL7, MCP-4 and TNFα) and antiatherogenic cytokines (IL33, IL16 and CXCL13), as well as with growth factors, such as TGF-β. On the one hand, in vitro suppression of SRGN expression in monocytes led to a reduction in the anti-inflammatory M2-polarized phenotype, while M1 pro-inflammatory macrophages were unskewed. Furthermore, our in vitro studies showed that upon SRGN knockdown M2 macrophages retained more oxidized lipoproteins. Conclusions Our results suggest that SRGN may be a crucial modulator of inflammation in human atherosclerotic plaques, potentially by affecting the bioavailability of effector molecules such as growth factors and cytokines.

Carotid and aortic plaque imaging using 3D gradient-echo imaging and the three-point Dixon method with improved motion-sensitized driven-equilibrium (iMSDE)

BackgroundWe devised a method that combines the 3D-Dixon-gradientecho (GRE) method with an improved motion-sensitized driven-equilibrium (iMSDE) to suppress blood flow signals. PurposeThe purpose of this study was to evaluate the effectiveness of the new method we developed plaque imaging method (3D-Dixon-GRE with the iMSDE method). Study typeRetrospective cohort. PopulationThirty-nine patients who underwent cervical plaque imaging.FIELD STRENGTH/SEQUENCE:3.0 T/3D-GRE. AssessmentSignal intensities of the common carotid artery, aorta, plaque, muscle, and subcutaneous fat were measured through the VISTA and the 3D-Dixon-GRE with iMSDE methods, and each contrast was calculated. Statistical testUsed the Mann Whitney U test. P-values below 0.05 were considered statistically significant. ResultsPlaque and muscle contrast estimated through the VISTA method and 3D-Dixon-GRE with iMSDE method was 1.60 ± 0.96 and 2.04 ± 1.06, respectively, (P < 0.05). The contrast between the flow (common carotid artery and Aorta) and muscle according to the VISTA method and 3D-Dixon-GRE with iMSDE method was 0.24 ± 0.11 and 0.40 ± 0.12, respectively (P < 0.001). Finally, the mean contrast for subcutaneous fat and muscle at six locations was 3.05 ± 1.25 and 0.81 ± 0.23 for the VISTA method and 3D-Dixon-GRE with the iMSDE method, respectively (P < 0.001). Data conclusionCompared to the conventional method (VISTA), the 3D-Dixon-GRE with iMSDE method is preferable in relation to the fat suppression effect, but it is disadvantageous regarding blood flow signal suppression. Therefore, the 3D-Dixon-GRE with the iMSDE method could be considered useful for plaque imaging.

Preoperative Evaluation for Carotid Endarterectomy Using CT and MRI Fusion Images Without Contrast Media.

The usefulness of carotid endarterectomy (CEA) for carotid artery stenosis has been established even in the era of endovascular treatment. Digital subtraction angiography (DSA) and three-dimensional computed tomography angiography (3D-CTA) are used for preoperative evaluation of CEA; however, contrast agents cannot be used in patients with renal dysfunction or contrast agent allergy. Since the introduction of a three-dimensional image analysis software, SYNAPSE VINCENT (Fujifilm, Tokyo, Japan) in February 2016, we initially fused cervical CT, carotid three-dimensional time-of-flight magnetic resonance angiography, and carotid plaque imaging using 1.5 T magnetic resonance imaging to evaluate carotid artery stenosis in patients with renal dysfunction. Since then, we have gradually accumulated several cases, and at present, this fusion imaging is our first choice for preoperative evaluation of CEA instead of DSA or 3D-CTA. This evaluation method has many advantages over DSA and 3D-CTA, including the fact that it does not require contrast media. We report its usefulness, limitations, and cautions.

Abstract WMP61: Assessment of Carotid Artery Plaques With Chemical Exchange Saturation Transfer Imaging

Background: Assessing carotid artery plaques in stenosis is crucial for treatment strategies and safety. Chemical exchange saturation transfer (CEST)-MRI, particularly Amide proton transfer (APT) imaging, shows promise in molecular imaging. This study explores the correlation between APT imaging and histopathological findings of carotid artery plaques in 34 consecutive patients who had carotid endarterectomy. We investigated the utility of CEST-MRI as a preoperative plaque diagnostic tool. Methods: APT imaging evaluated plaques prior to the procedures. APT signal values were derived from concentration maps. Plaques were categorized into Group A (APT signal values ≥ 1.90 E-04) and Group B (APT signal values &lt; 1.90 E-04). Postoperative histopathological assessments were conducted on the excised plaques. Histology slides were categorized following AHA’s classification, distinguishing type VI lesions with intraplaque hemorrhage from non-type VI lesions. Results: Type VI lesions accounted for 64.7% (22 cases), while non-type VI lesions were 35.3% (12 cases). Type VI group showed significantly higher mean APT signal values (2.72 ± 1.96 E-04) compared to non-type VI group (0.70 ± 0.59 E-04) (p &lt; 0.001). Pathologically, Group A had a significantly higher proportion of Type VI lesions (100%) than Group B (45%) (p &lt; 0.01). Symptomatic patients or patients with worsening stenosis rates were significantly higher in Group A (75%) than Group B (36%) (p &lt; 0.01). Conclusion: Elevated APT signals were observed in unstable plaques with intraplaque hemorrhage and in plaques of symptomatic or progressive stenosis patients. CEST-MRI evaluation is valuable for assessing plaque characteristics and activity.

Atherosclerotic plaque features relevant to rupture-risk detected by clinical photon-counting CT ex vivo: a proof-of-concept study

BackgroundTo identify subjects with rupture-prone atherosclerotic plaques before thrombotic events occur is an unmet clinical need. Thus, this proof-of-concept study aims to determine which rupture-prone plaque features can be detected using clinically available photon-counting computed tomography (PCCT).MethodsIn this retrospective study, advanced atherosclerotic plaques (ex vivo, paraffin-embedded) from the Carotid Plaque Imaging Project were scanned by PCCT with reconstructed energy levels (45, 70, 120, 190 keV). Density in HU was measured in 97 regions of interest (ROIs) representing rupture-prone plaque features as demonstrated by histopathology (thrombus, lipid core, necrosis, fibrosis, intraplaque haemorrhage, calcium). The relationship between HU and energy was then assessed using a mixed-effects model for each plaque feature.ResultsPlaques from five men (age 79 ± 8 [mean ± standard deviation]) were included in the study. Comparing differences in coefficients (b1diff) of matched ROIs on plaque images obtained by PCCT and histology confirmed that calcium was distinguishable from all other analysed features. Of greater novelty, additional rupture-prone plaque features proved discernible from each other, particularly when comparing haemorrhage with fibrous cap (p = 0.017), lipids (p = 0.003) and necrosis (p = 0.004) and thrombus compared to fibrosis (p = 0.048), fibrous cap (p = 0.028), lipids (p = 0.015) and necrosis (p = 0.017).ConclusionsClinically available PCCT detects not only calcification, but also other rupture-prone features of human carotid plaques ex vivo.Relevance statementImproved atherosclerotic plaque characterisation by photon-counting CT provides the ability to distinguish not only calcium, but also rupture-prone plaque features such as haemorrhage and thrombus. This may potentially improve monitoring and risk stratification of atherosclerotic patients in order to prevent strokes.Key points• CT of atherosclerotic plaques mainly detects calcium.• Many components, such as intra-plaque haemorrhage and lipids, determine increased plaque rupture risk.• Ex vivo carotid plaque photon-counting CT distinguishes haemorrhage and thrombus.• Improved plaque photon-counting CT evaluation may refine risk stratification accuracy to prevent strokes.Graphical

Prognostic impact of carotid plaque imaging using total plaque area added to SCORE2 in middle-aged subjects: the ARteris Cardiovascular Outcome (ARCO) cohort study.

Many cardiovascular events occur in seemingly healthy individuals.We set out to assess the predictive value of atherosclerosis imaging in combination with cardiovascular risk calculators in subjects aged 40-65 years. We compared PROCAM (PROspective CArdiovascular Münster study), SCORE (Systematic COronary Risk Evaluation) and SCORE2 with carotid ultrasound (total plaque area, TPA) in subjects without cardiovascular disease. In this prospective cohort study, follow-up was obtained by phone or mail from patients; or from clinical records, if needed. In 2842 subjects (mean age 50±8 years; 38% women), cardiovascular events occurred in 154 (5.4%) of them over an mean follow-up period of 5.9 (range 1-12) years, specifically: 41 cases of AMI (myocardial infarction), 16 strokes, 21 CABG (coronary artery bypass grafting), 41 PTCA (percutaneous transluminal coronary angioplasty) and 35 CAD (coronary artery disease). Mean PROCAM risk was 5±6%, mean SCORE risk was 1.3±1.6% and mean SCORE2 risk was 5±3%. Both for the primary outcome (major adverse cardiovascular events, MACEs, i.e. AMI + strokes) and the secondary outcome (atherosclerotic cardiovascular disease, ASCVD, i.e. MACEs + CABG + CAD + PTCA), hazards increased significantly for TPA tertiles and SCORE2 post-test risk between 6.7 to 12.8 after adjustment for risk factors (age, smoke, sex, systolic blood pressure, lipids, medication) and after adjustment for results from PROCAM, SCORE and SCORE2. Model performance was statistically improved regarding model fit in all models using TPA. Net reclassification improvement for SCORE2 with TPA post-test risk increased significantly by 24% for MACEs (p = 0.01) and 39% for ASCVD (p <0.0001). Integration of TPA post-test risk into SCORE2 adds prognostic information, supporting the use of carotid ultrasound when assessing ASCVD risk in subjects aged 40-65 years.

Optoacoustic biomarkers of lipids, hemorrhage and inflammation in carotid atherosclerosis.

Imaging plays a critical role in exploring the pathophysiology and enabling the diagnostics and therapy assessment in carotid artery disease. Ultrasonography, computed tomography, magnetic resonance imaging and nuclear medicine techniques have been used to extract of known characteristics of plaque vulnerability, such as inflammation, intraplaque hemorrhage and high lipid content. Despite the plethora of available techniques, there is still a need for new modalities to better characterize the plaque and provide novel biomarkers that might help to detect the vulnerable plaque early enough and before a stroke occurs. Optoacoustics, by providing a multiscale characterization of the morphology and pathophysiology of the plaque could offer such an option. By visualizing endogenous (e.g., hemoglobin, lipids) and exogenous (e.g., injected dyes) chromophores, optoacoustic technologies have shown great capability in imaging lipids, hemoglobin and inflammation in different applications and settings. Herein, we provide an overview of the main optoacoustic systems and scales of detail that enable imaging of carotid plaques in vitro, in small animals and humans. Finally, we discuss the limitations of this novel set of techniques while investigating their potential to enable a deeper understanding of carotid plaque pathophysiology and possibly improve the diagnostics in future patients with carotid artery disease.

LIGHT/TNFSF14 levels in carotid atherosclerotic plaques are associated with symptomatic cerebrovascular disease

Abstract Background Plaque rupture is the underlying cause of most cardiovascular events, such as stroke and myocardial infarction. Co-stimulatory molecules, the immune checkpoints, are emerging as strong candidates to battle atherosclerosis progression. The co-stimulatory molecule LIGHT (tumour necrosis factor 14; TNFSF14) exists in foam cell-rich regions of atherosclerotic plaques, but whether it has a driving role in promoting a high-risk plaque phenotype is not known. Purpose This study investigates the association between intra-plaque LIGHT and plaque vulnerability. Methods Plaque levels of LIGHT/TNFSF14 were measured in homogenised carotid endarterectomy plaques by Proximity Extension Assay (PEA) in subjects from the Carotid Plaque Imaging Cohort (CPIP; N=201). Homogenates were further examined by multi-plex cytokine analysis and ELISA, and tissue plaque sections through histology/immunohistochemistry. Results Plaque levels of LIGHT were associated with the occurrence of pre-operative cerebrovascular symptoms (p=0.00014). Furthermore, LIGHT correlated strongly with the histological plaque vulnerability index (p=5x10-15): a ratio between the sum of destabilising versus stabilising plaque components (i.e. macrophages, intra-plaque haemorrhage and lipids versus smooth muscle cells and collagen) as well as with necrotic core size and the inflammatory cytokines interleukin(IL)-1β, IL-6, chemokine (C-C motif) ligand (CCL)-2, CCL4 and CCL5. Moreover, plaque LIGHT levels correlated with several components of the extracellular matrix turnover machinery, including cleaved collagen, the collagen cross-linking proteoglycans fibromodulin and lumican, the matricellular protein COMP (cartilage oligomeric matrix protein), and the remodelling regulator ADAMTS7 (a disintegrin and metalloproteinase with thrombospondin motifs-7). Levels also correlated with matrix metalloproteinases (MMPs) 1, 2, 9 and 10, and tissue inhibitor of metalloproteinase (TIMP)-1. Conclusion Expression of LIGHT in atherosclerotic plaques does not only correlate with markers of plaque destabilisation¸ but is also significantly elevated in plaques from symptomatic, compared to asymptomatic, patients. These results connect LIGHT content to a rupture-prone plaque phenotype and suggest the LIGHT signalling pathway as a potential therapeutic target to promote atherosclerotic plaque stability.

Clinical Applications of 3.0t High Resolution Magnetic Resonance Imaging (HRMRI) in the Analysis of Carotid Artery Plaques

Objective: Use of head and neck coils through a 3.0T high resolution magnetic resonance imaging (HRMRI) scanner to scan and analyze extra cranial carotid artery plaque components for its nature, composition, stability, wall thickness, and lumen stenosis. Methods: Ten patients (3 females and 7 males) with 50-99% stenosis of the carotid artery due to atherosclerotic plaque formation were used in this study. They were selected from a pool of hospitalized patients at a university medical center between May and November of 2017. Gadodiamide was injected to contrast the magnetic resonance imaging (MRI) scan image. This was then imported into the carotid artery plaque imaging analysis software for evaluation. Results: Analytical results of HRMRI analysis of plaque stratification in patients with right carotid artery plaques: area unit of mm2 - levels 4 through 7 showing 0 because the areas had only carotid artery without plaque components. Conclusion: The 3.0T HRMRI scanner can accurately analyze carotid artery plaque composition, morphology, and the percentage of stenosis. This technique maybe used as an atraumatic non-radiation study to assess the severity and stability of carotid artery plaques, and in the prediction of risks for embolic stroke.

Circulating soluble IL-6 receptor associates with plaque inflammation but not with atherosclerosis severity and cardiovascular risk

BackgroundThe residual cardiovascular risk in subjects receiving guideline-recommended therapy is related to persistent vascular inflammation and IL-6 represents a target for its treatment. IL-6 binds to receptors on leukocytes and hepatocytes and/or by forming complexes with soluble IL-6 receptors (sIL-6R) binding to gp130 which is present on all cells. Here we aimed to estimate the associations of these two pathways with risk of cardiovascular disease (CVD). MethodsIL-6 and sIL-6R were analyzed using the proximity extension assay. Baseline plasma samples were obtained from participants in the prospective Malmö Diet and Cancer (MDC) study (n = 4661), the SUMMIT VIP study (n = 1438) and the Carotid Plaque Imaging Project (CPIP, n = 285). Incident clinical events were obtained through national registers. Plaques removed at surgery were analyzed by immunohistochemistry and biochemical methods. ResultsDuring 23.1 ± 7.0 years follow-up, 575 subjects in the MDC cohort suffered a first myocardial infarction. Subjects in the highest tertile of IL-6 had an increased risk compared to the lowest tertile (HR and 95% CI 2.60 [2.08–3.25]). High plasma IL-6 was also associated with more atherosclerosis, increased arterial stiffness, and impaired endothelial function in SUMMIT VIP, but IL-6 was only weakly associated with plaque inflammation in CPIP. sIL-6R showed no independent association with risk of myocardial infarction, atherosclerosis severity or vascular function, but was associated with plaque inflammation. ConclusionsOur findings show that sIL-6R is a poor marker of CVD risk and associated vascular changes. However, the observation that sIL-6R reflects plaque inflammation highlights the complexity of the role of IL-6 in CVD.

Deep learning assisted classification of spectral photoacoustic imaging of carotid plaques

Spectral photoacoustic imaging (sPAI) is an emerging modality that allows real-time, non-invasive, and radiation-free assessment of tissue, benefiting from their optical contrast. sPAI is ideal for morphology assessment in arterial plaques, where plaque composition provides relevant information on plaque progression and its vulnerability. However, since sPAI is affected by spectral coloring, general spectroscopy unmixing techniques cannot provide reliable identification of such complicated sample composition. In this study, we employ a convolutional neural network (CNN) for the classification of plaque composition using sPAI. For this study, nine carotid endarterectomy plaques were imaged and were then annotated and validated using multiple histological staining. Our results show that a CNN can effectively differentiate constituent regions within plaques without requiring fluence or spectra correction, with the potential to eventually support vulnerability assessment in plaques.

Assessment of stroke risk using MRI-VPD with automatic segmentation of carotid plaques and classification of plaque properties based on deep learning

PurposeThe primary goal of this study is to establish a technique for categorizing MRI scans into two distinct groups, namely, vulnerable and stable carotid plaques, for the purpose of evaluating risk of stroke levels based on imaging of carotid plaque. MethodThe study data was obtained from two hospitals and included cases of both stable and vulnerable conditions. The cohort comprised of 87 patients with established risk factors for atherosclerosis. A total of 3741 MRI scans were utilized, with each category evenly represented and randomly split into training and testing sets at a ratio of 70:30, respectively. Our methodology utilized the U-Net model for automatic extraction of the region of interest (ROI) from the MRI scans and subsequent plaque image segmentation, followed by the implementation of pre-trained ResNet-50 models for classification. ResultsOur proposed framework involved the integration of two deep learning models, namely U-net and ResNet-50, with hyperparameters fine-tuned and adjusted based on our classification problem. We attained the highest accuracy of 94.11% using our proposed framework, thus highlighting the efficacy of our approach. ConclusionOur study indicates that pre-trained deep learning models have the potential to classify MRI scans based on carotid plaque imaging with fine-tuning. The proposed framework can help reduce erroneous diagnoses caused by suboptimal image quality or individual expertise. Furthermore, our framework can assist radiologists in making better decisions for patient care. In conclusion, this study provides a useful tool for the assessment of stroke risk levels, which can ultimately improve patient outcomes.