Evaluation of Carotid Plaque Rupture and Neovascularization by Contrast-Enhanced Ultrasound Imaging: an Exploratory Study Based on Histopathology

A Visualized Nomogram to Predict the Risk of Acute Ischemic Stroke Among Patients With Cervical Artery Dissection

Background

Acute ischemic stroke (AIS) is a significant global health concern, with cervical artery dissection (CAD) being a notable yet frequently overlooked cause, particularly in young adults. Despite advancements in imaging technologies, there remains a deficiency in effective methodologies for the prompt identification of AIS attributable to CAD. This research aims to create a predictive model combining clinical, imaging, and laboratory data to improve risk stratification and guide timely interventions.

Methods

Between 2019 and 2024, patients diagnosed with CAD were enrolled in the study. Nomogram models were constructed utilizing a two-step methodological approach. Initially, the least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to improve variable selection. Subsequently, logistic regression analysis was conducted to develop an estimation model using the significant indicators identified by the LASSO. The model's accuracy was evaluated using the application of receiver operating characteristic (ROC) curves, calibration curves, decision curve analyses, and clinical impact curves. The model underwent internal validation through bootstrap resampling with 1,000 iterations.

Results

In the cohort of 102 patients, 75 individuals with CAD experienced had an acute ischemic stroke. This cohort was characterized by a significantly older median age (42 years vs 51 years, p=0.041) and a comparable proportion of males (78.7% vs 74.1%,p=0.825). The analysis identified hyperlipidemia (aOR=0.19, 95% CI=0.040-0.893, p=0.036), lumen occlusion (aOR=5.41, 95% CI=1.236-23.648, p=0.025), a lower lymphocyte-to-monocyte ratio (LMR) (aOR=0.68, 95% CI=0.476-0.797, p=0.038), and higher systemic immune-inflammation index (SII) (aOR=1.01, 95% CI=1.001-1.016, p=0.026) are independent factors linked to ischemic stroke in CAD patients. The predictive model showed strong performance with an AUC of 0.870 (95% CI=0.789-0.950) under the ROC curve. Decision curve analysis (DCA) indicated that the constructed nomogram was clinically applicable, with a risk threshold ranging from 9% to 95%.

Conclusion

This study developed a dynamic and visualized nomogram model for the precise prediction of stroke risk in patients with CAD, exhibiting robust performance, calibration, and clinical utility. Future multi-center studies are anticipated to further substantiate its clinical applicability.

Recent Advances in Micro/Nanomotor for the Therapy and Diagnosis of Atherosclerosis

Atherosclerotic cardiovascular disease poses a significant global public health threat with a high incidence that can result in severe mortality and disability. The lack of targeted effects from traditional therapeutic drugs on atherosclerosis may cause damage to other organs and tissues, necessitating the need for a more focused approach to address this dilemma. Micro/nanomotors are self-propelled micro/nanoscale devices capable of converting external energy into autonomous movement, which offers advantages in enhancing penetration depth and retention while increasing contact area with abnormal sites, such as atherosclerotic plaque, inflammation, and thrombosis, within blood vessel walls. Recent studies have demonstrated the crucial role micro/nanomotors play in treating atherosclerotic cardiovascular disease. Hence, this review highlights the recent progress of micro/nanomotor technology in atherosclerotic cardiovascular disease, including the effective promotion of micro/nanomotors in the circulatory system, overcoming hemorheological barriers, targeting the atherosclerotic plaque microenvironment, and targeting intracellular drug delivery, to facilitate atherosclerotic plaque localization and therapy. Furthermore, we also describe the potential application of micro/nanomotors in the imaging of vulnerable plaque. Finally, we discuss key challenges and prospects for treating atherosclerotic cardiovascular disease while emphasizing the importance of designing individualized management strategies specific to its causes and microenvironmental factors.

The value of contrast-enhanced ultrasound in assessing carotid plaque vulnerability and predicting stroke risk

The presence of vulnerable carotid plaques plays a critical role in ischemic stroke pathogenesis, with intraplaque neovascularization (IPN) serving as a key indicator of plaque instability. Contrast-enhanced ultrasound (CEUS) provides a comprehensive evaluation of both plaque surface morphology and microvascular features. This study assesses the utility of CEUS in identifying vulnerable carotid plaques, quantifying IPN, and predicting stroke risk. The study involved 91 patients with carotid stenosis who underwent carotid endarterectomy (CEA). Preoperative assessments included CEUS and high-resolution magnetic resonance imaging (HR-MRI). Following surgery, plaque samples were collected and subjected to pathological analysis. CEUS offered comprehensive morphological insights, categorizing plaques by the direction of diffusion into inside-out and non-inside-out types. Neovascularization was semi-quantitatively evaluated using CEUS. HR-MRI and pathological assessments identified the composition and vulnerability of plaques. Microvessel density (MVD), microvessel area (MVA), and microvessel ratio (MVR) in plaque sections were quantified using high-power microscopy. Among the 91 subjects, 53 had a history of symptomatic stroke, while 38 had experienced asymptomatic stroke events. The analysis identified a significant association between symptomatic stroke events and fibrous cap rupture (FCR), as indicated by CEUS (P = 0.032), contrast agent diffusion within the plaque (P = 0.002), and a semi-quantitative grade 3 neovascularization (P = 0.007). Regression analysis further established CEUS grade 3 as an independent predictor of symptomatic stroke events (OR = 3.39, 95% CI: 1.25-9.19). CEUS showed comparable sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in identifying vulnerable plaques when compared to HR-MRI, with slightly superior values for CEUS; however, the differences did not reach statistical significance (P = 0.503). Plaques demonstrating inside-out contrast agent diffusion had a markedly higher incidence of FCR and intraplaque hemorrhage (IPH) than those without such diffusion (P < 0.001). A positive correlation existed between the CEUS grade and both MVD and MVR (P < 0.001), but no significant relationship was observed with MVA (P = 0.221). Additionally, a significant association was found between the CEUS grade and IPH (P = 0.008). In summary, this study emphasizes the utility of CEUS in identifying vulnerable carotid plaques and evaluating neovascularization, both of which correlate with stroke risk. Notably, a CEUS grade 3 score may serve as an independent predictor of symptomatic stroke. This evidence supports the potential of CEUS as an effective, non-invasive method for assessing carotid plaque instability and identifying individuals at elevated risk for stroke.

Incremental clinical value of intraplaque neovascularization in predicting recurrent ischemic stroke

OBJECTIVE

Carotid intraplaque neovascularization (IPN) detected by contrast-enhanced ultrasound (CEUS) is a risk factor for recurrent ischemic stroke. However, it is still unclear whether IPN can be used to accurately identify patients with recurrent ischemic stroke in clinical practice. Herein, we investigated the clinical predictive value of IPN for recurrent ischemic stroke in a real-world setting.

METHODS

We enrolled 200 patients with ischemic stroke and atherosclerotic carotid stenosis who were followed up for 2 years. The endpoint was recurrent ischemic stroke. Cox regression and subgroup analyses were employed to assess whether treatment affected the relationship between IPN and recurrent ischemic stroke. The net classification index (NRI) and integrated discriminant improvement index (IDI) were used to validate the additional clinical value of IPN in identifying recurrent ischemic stroke.

RESULTS

During the 2-year follow-up, 36 patients experienced recurrent ischemic stroke. Cox regression analyses showed that IPN (grade 2), hypoechoic plaque, high homocysteine levels, and smoking were independent risk factors for recurrent ischemic stroke. Additional IPN evaluation may increase the NRI (0.512; 95% confidence interval [CI]: 0.083-0.624) and IDI (0.151; 95% CI: 0.010-0.213) for identifying high-risk patients with recurrent ischemic stroke. In addition, in the subgroup undergoing revascularization, the proportion of IPN (grade 2) was significantly higher in patients with recurrent ischemic stroke than in patients with nonrecurrent ischemic stroke (p = 0.001).

INTERPRETATION

In clinical settings, IPN, assessed by CEUS, may provide additional clinical value for predicting recurrent ischemic stroke, helping to identify patients with ischemic stroke who require close follow-up.

The role of intraplaque neovascularization in recent and future ischemic stroke in patients with mild carotid stenosis

PURPOSE

There is still insufficient evidence for predicting stroke risk in patients with mild carotid atherosclerotic stenosis. This study aimed to explore the association between carotid intraplaque neovascularization (IPN) in mild stenosis and ischemic stroke, using contrast-enhanced ultrasound (CEUS) imaging.

METHODS

This retrospective observational study included 369 patients from July 2021 to March 2022. These patients were categorized as symptomatic or asymptomatic based on their recent history of ipsilateral ischemic stroke. Initial parameters of carotid plaques, such as IPN grading and contrast enhancement index, were assessed using B-mode ultrasonography and CEUS. The follow-up period lasted 12 months or until a newly-developed ischemic stroke occurred. Logistic regression models and Cox proportional-hazards regression models were employed to explore the associations between ultrasonic parameters and the incidence of recent and future ischemic strokes.

RESULTS

In patients with mild stenosis, both increasing age and grade 2 carotid IPN were significant predictors of recent primary ischemic stroke. Furthermore, grade 2 carotid IPN independently predicted future ischemic strokes in both symptomatic and asymptomatic patients.

CONCLUSION

This study demonstrated that carotid IPN as detected by CEUS imaging holds potential as a useful non-invasive biomarker for predicting recent and future ischemic strokes in patients with mild carotid stenosis.

Relationship Between Subclavian Artery Stenosis Lesions and Posterior Circulation Infarction: A Preliminary Study

BACKGROUND

To investigate the correlation between subclavian steal syndrome and posterior circulation infarction using magnetic resonance imaging.

METHODS

A total of 294 patients diagnosed with subclavian steal syndrome using carotid Doppler ultrasonography were retrospectively included. According to the magnetic resonance imaging results, they were divided into posterior circulation infarction group and nonposterior circulation infarction group. Clinical indicators and carotid Doppler ultrasound parameters of patients were collected, and they were screened to establish a multiple logistic regression model. Receiver operating characteristic curve analysis of the established multiple logistic regression model was performed, and the area under the curve was calculated to evaluate the predictive efficiency of the model.

RESULTS

After statistical analysis of all parameters of the 2 groups of patients, a total of 10 parameters were included in multiple logistic regression to establish a model. The results showed a correlation between posterior circulation infarction and subclavian artery occlusion, grade III subclavian steal syndrome, gender, vulnerable plaques, National Institutes of Health Stroke Scale score, and age. After the receiver operating characteristic curve analysis of the model, the area under the curve for the multiple logistic regression model was 0.773.

CONCLUSIONS

The multiparameter composite model based on clinical baseline data and carotid Doppler ultrasonography parameters can effectively predict posterior circulation infarction and offer novel insight for clinical diagnosis.

Diagnostic accuracy of carotid plaque instability by noninvasive imaging: a systematic review and meta-analysis

AIMS

There is increasing evidence that plaque instability in the extracranial carotid artery may lead to an increased stroke risk independently of the degree of stenosis. We aimed to determine diagnostic accuracy of vulnerable and stable plaque using noninvasive imaging modalities when compared to histology in patients with symptomatic and asymptomatic carotid atherosclerosis.

METHODS AND RESULTS

Medline Ovid, Embase, Cochrane Library, and Web of Science were searched for diagnostic accuracy of noninvasive imaging modalities (CT, MRI, US) in the detection of 1) vulnerable/stable plaque, and 2) vulnerable/stable plaque characteristics, compared to histology. The quality of included studies was assessed by QUADAS-2 and univariate and bivariate random-effect meta-analyses were performed. We included 36 vulnerable and 5 stable plaque studies in the meta-analysis, and out of 211 plaque characteristics from remaining studies, we classified 169 as vulnerable and 42 as stable characteristics (28 CT, 120 MRI, 104 US characteristics). We found that MRI had high accuracy [90% (95% CI: 82-95%)] in the detection of vulnerable plaque, similar to CT [86% (95% CI: 76-92%); P > 0.05], whereas US showed less accuracy [80% (95% CI: 75-84%); P = 0.013]. CT showed high diagnostic accuracy in visualizing characteristics of vulnerable or stable plaques (89% and 90%) similar to MRI (86% and 89%; P > 0.05); however, US had lower accuracy (77%, P < 0.001 and 82%, P > 0.05).

CONCLUSION

CT and MRI have a similar, high performance in detecting vulnerable carotid plaques, whereas US showed significantly less diagnostic accuracy. Moreover, MRI visualized all vulnerable plaque characteristics allowing for a better stroke risk assessment.

REGISTRATION

PROSPERO ID CRD42022329690.

Association of cardiovascular risk factors and intraplaque neovascularization in symptomatic carotid plaque

Background and purpose

Cardiovascular risk factors are known to contribute to the formation of atherosclerotic plaques, which can result in carotid stenosis. However, the extent to which these factors are associated with intraplaque neovascularization, a key indicator of plaque vulnerability, remains unclear. To investigate this relationship, a study was conducted utilizing contrast-enhanced ultrasound (CEUS) to assess intraplaque neovascularization in symptomatic patients.

Methods

A cohort of 157 symptomatic patients underwent evaluation using Contrast-Enhanced Ultrasound (CEUS) imaging to assess carotid intraplaque neovascularization, which was quantified based on the degree of plaque enhancement. The collected data encompassed baseline patient characteristics, results from biochemical examinations, cardiovascular risk factors, and medication usage history. Regression analyses were conducted to elucidate the relationship between carotid plaque neovascularization and various cardiovascular risk factors.

Results

Patients with intraplaque neovascularization were more prone to have diabetes mellitus (OR 3.81, 95% CI 1.94-7.46, p < 0.001), dyslipidemia (OR 2.36, 95% CI 1.22-4.55, p = 0.011) and hypertension (OR 2.92, 95% CI 1.50-5.71, p = 0.002). Smoking increased the risk of having intraplaque neovascularization (OR 2.25, 95% CI 1.12-4.54, p = 0.023). Treatment with statins was significantly lower in patients with intraplaque neovascularization (OR 0.37, 95% CI 0.19-0.72, p = 0.003). In the multivariate analysis, diabetes mellitus (OR 3.27, 95% CI 1.10-9.78, p = 0.034) was independently related to the presence of intraplaque neovascularization. Meanwhile, compared to the patients in the first tertile of serum glucose (< 6.20 mmol/L), the patients in the third tertile (> 13.35 mmol/L) had the most significance of intraplaque neovascularization (OR 5.55, 95% CI 1.85-16.66, p = 0.002).

Conclusion

The findings indicated that diabetes mellitus is a significant cardiovascular risk factor that is strongly associated with carotid intraplaque neovascularization.

Real-time Elastography and Contrast-Enhanced Ultrasound for Evaluating Adventitia in the Early Diagnosis of Vulnerable Plaques: an Exploratory Study Based on Histopathology

Vulnerable plaque is closely related to the occurrence of ischemic stroke. Therefore, early accurate identification of plaque vulnerability is crucial in risk stratification. In the development of vulnerable plaques, the change of the adventitia is earlier than that of the intima. Currently, researchers focused on the ultrasound detection of intraplaque and intima, but adventitia was often ignored in the examination. Real-time elastography technology (RTE) provides an estimation of adventitia stiffness, and contrast-enhanced ultrasound (CEUS) provides the quantification of adventitial VV. Therefore, we aimed to evaluate the value of adventitia in the early diagnosis of plaque vulnerability by combining CEUS and RTE based on histopathology. Rabbit carotid atherosclerosis models were established, and CEUS and RTE were performed. Normalized maximal video-intensity enhancement (MVE) was calculated to quantify adventitial VV density, and strain values were acquired to evaluate the adventitial elasticity. After removal of the lesion lumen, histological analysis of each excised plaque and adventitia was performed, and vulnerable plaques (n = 32) and stable group (n = 13) were distinguished. Normalized MVE of the adventitial VV and adventitial strain values in the vulnerable group was significantly higher than those in the stable group. Normalized MVE and strain values had a positive linear correlation with histological findings. Normalized MVE of the adventitial VV combined with adventitial strain values could identify plaque vulnerability with the area under the curve of 0.913 (sensitivity 90% and specificity 97%). Accordingly, the multimodal ultrasound detection strategy of adventitia has a high diagnostic value for early plaque vulnerability.

Explore the value of carotid ultrasound radiomics nomogram in predicting ischemic stroke risk in patients with type 2 diabetes mellitus

Background and objective

Type 2 Diabetes Mellitus (T2DM) with insulin resistance (IR) is prone to damage the vascular endothelial, leading to the formation of vulnerable carotid plaques and increasing ischemic stroke (IS) risk. The purpose of this study is to develop a nomogram model based on carotid ultrasound radiomics for predicting IS risk in T2DM patients.

Methods

198 T2DM patients were enrolled and separated into study and control groups based on IS history. After manually delineating carotid plaque region of interest (ROI) from images, radiomics features were identified and selected using the least absolute shrinkage and selection operator (LASSO) regression to calculate the radiomics score (RS). A combinatorial logistic machine learning model and nomograms were created using RS and clinical features like the triglyceride-glucose index. The three models were assessed using area under curve (AUC) and decision curve analysis (DCA).

Results

Patients were divided into the training set and the testing set by the ratio of 0.7. 4 radiomics features were selected. RS and clinical variables were all statically significant in the training set and were used to create a combination model and a prediction nomogram. The combination model (radiomics + clinical nomogram) had the largest AUC in both the training set and the testing set (0.898 and 0.857), and DCA analysis showed that it had a higher overall net benefit compared to the other models.

Conclusions

This study created a carotid ultrasound radiomics machine-learning-based IS risk nomogram for T2DM patients with carotid plaques. Its diagnostic performance and clinical prediction capabilities enable accurate, convenient, and customized medical care.

Diagnostic value of contrast-enhanced ultrasound in the activity of idiopathic retroperitoneal fibrosis: a retrospective study

OBJECTIVES

To explore the diagnostic value of contrast-enhanced ultrasound (CEUS) in the disease activity of idiopathic retroperitoneal fibrosis (IRPF).

METHODS

This retrospective study included 148 CEUS examinations from 63 patients with IRPF treated in our hospital from April 2016 to September 2021. They were divided into two groups: IRPF active group (69 examinations) and inactive group (79 examinations). Uni- and multivariable analyses were used to identify independent risk factors for IRPF activity. Receiver operating characteristic (ROC) curves were drawn to establish different diagnostic models to evaluate the diagnostic value of IRPF activity. The z test was used to compare the differences of the area under the curves (AUCs). The value of CEUS in evaluating the variation of disease activity over time was also investigated between repeat patient studies.

RESULTS

Univariate and multivariate logistic regression analyses revealed the thickness [odds ratio (OR) = 14.125, 95% confidence interval (CI) = 3.017-66.123] was the most significant independent risk factor for IRPF activity (P < 0.01). The best diagnostic model was model 3, which was established by CEUS score combined with thickness. The AUC was 0.944 (95%CI = 0.912-0.977), and the sensitivity and specificity were 89.86% and 86.08%, respectively. The diagnostic performance was not significantly improved after combining clinical symptom (back pain) and laboratory indicators [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)]. Compared with before treatment, the CEUS score and thickness were significantly decreased after treatment (x2 = 14.580, P < 0.001 and z = 4.708, P < 0.001, respectively).

CONCLUSION

CEUS has good diagnostic value for IRPF disease activity. Key points • Thickness and contrast-enhanced ultrasound score were significantly higher in the active group than those in inactive group (P < 0.001). • With thickness of 4 mm and contrast-enhanced ultrasound 2 score as optimal cut-off values, the sensitivity and specificity were 89.86%, 81.01% and 52.17%, 100.00%, respectively. • During follow-up, when the disease progressed, the change of CEUS score was earlier than the change of thickness.

Multiple techniques to evaluate the relationship between carotid artery plaque and acute stroke

AIM

To evaluate the important characteristics of the plaque vulnerability using multimodal ultrasound imaging methods (2D, contrast-enhanced ultrasound, and elastography), and to explore the relationship between plaque and acute stroke.

METHODS

A total of 244 patients with carotid plaque were enrolled, including 104 patients with acute stroke ipsilateral to the plaque as the case group and 140 patients as the control group. All patients underwent conventional carotid ultrasound, contrast-enhanced ultrasound (CEUS) and elastography (SWE). The results of each examination were compared and analyzed, and the relationship between the results and the occurrence of stroke was discussed.

RESULTS

In the acute stroke group, the men, with a history of alcohol consumption the direction of contrast media diffusion was higher than that in the control group, but the plaque gray value (GSM), maximum, average and minimum Young's elastic modulus imaging values (YM) were slightly lower than those in the control group (P < 0.05). Logistic regression analysis showed that waist to body ratio (WHtR), GSM, YM, neovascularization density and contrast diffusion direction were independent risk factors for predicting acute ischemic stroke. The influence degree of each factor from strong to weak was waist to body ratio, neovascularity density, GSM and YM, respectively. The area under the curve (AUC) for the diagnosis of acute ischemic stroke by regression model was 0.746.

CONCLUSION

The combination of multiple ultrasound techniques to evaluate the vulnerability of carotid plaque and predict the occurrence of acute stroke provides valuable information for clinical decision making.

Contrast-enhanced ultrasound reveals free-floating thrombus in carotid artery: The cause of stroke is surprisingly plaque rupture

BACKGROUND

Acute stroke poses a serious threat to people's health. The occurrence of a thrombus following the rupture of vulnerable plaques in the carotid artery is a significant contributor to the development of stroke. In previous case reports, it has been challenging to visualize tiny ulcerations within carotid artery plaques using computed tomography angiography (CTA) and digital subtraction angiography (DSA), even when the rupture of the plaque leads to the formation of a free-floating thrombus (FFT). However, in this particular case, contrast-enhanced ultrasound (CEUS) was able to overcome this limitation and provide a more precise assessment, confirming that the FFT formation was indeed a result of plaque rupture rather than any other potential causes. Cases that utilize CEUS to visualize the formation of ulcers and FFT resulting from plaque rupture are even more rare. As such, we present this case to shed light on this infrequent phenomenon.

CASE SUMMARY

In this case study, we present a 65-year-old male patient who was admitted to the hospital due to headache and abnormal mental behavior for one day. During the routine cervical artery ultrasound examination upon admission, we detected the presence of plaque in the right internal carotid artery of the patient, resulting in luminal stenosis. Additionally, we observed suspected hypoechoic material at the distal end of the plaque. After undergoing CEUS examination, it was definitively determined that an ulcer had formed and a FFT had developed due to the rupture of carotid artery plaque. Subsequent CTA and DSA examinations further confirmed the presence of the FFT. The magnetic resonance imaging (MRI) reveals an acute lacunar infarction in the head of the right caput nuclei caudate, which strengthens the potential link between the patient's neurological and psychiatric symptoms observed during admission. The patient received prompt antiplatelet therapy and underwent cervical artery stenting surgery with the assistance of a distal embolic protection device. Following the procedure, the patient was discharged on the fourth day and experienced a complete recovery.

CONCLUSION

CEUS is a valuable tool for visualizing FFT resulting from the rupture of vulnerable plaques in the carotid artery.

Contrast-enhanced ultrasound evaluation of plaque vulnerability and the relationship between peripheral blood leukocytes

OBJECTIVE

To evaluate plaque vulnerability by carotid contrast-enhanced ultrasound (CEUS) and to analyze the correlation between plaque vulnerability and peripheral blood leukocyte classification.

MATERIALS AND METHODS

135 patients with carotid plaque were examined by contrast-enhanced ultrasound. Plaque vulnerability was assessed by semiquantitative visual classification. Baseline clinical data and peripheral leukocyte classification were collected. Ordered logistic regression was used to analyze the correlation between plaque neovascularization grade and peripheral leukocyte classification count.

RESULTS

There were significant differences in leukocyte, monocyte, neutrophil, mean platelet volume, lymphocyte, and neutrophil counts between different neovascular plaque grades and peripheral blood (P < 0.05). Correlation analysis showed that leukocyte, monocyte, and neutrophil counts were significantly positively correlated.

CONCLUSION

The increase in plaque neovascularization is associated with an increase in circulating leukocytes, monocytes, and neutrophils. Therefore, CEUS combined with peripheral blood leukocytes may serve as an early warning of plaque vulnerability and provide a theoretical basis for clinical treatment.

Utility of ultrasound in the perioperative phase of carotid endarterectomy and carotid artery stent implantation

BACKGROUND

This article reviews the latest research results of the use of ultrasound technology in the perioperative period of carotid endarterectomy and carotid stenting and discusses the role of ultrasound technology in accurately evaluating carotid stenosis and plaque stability, assisting in selecting the most suitable surgical method, and providing optimal perioperative imaging to guide carotid endarterectomy (CEA) and carotid artery stenting (CAS) to reduce the occurrence and progression of stroke.

METHODS

The research published in recent years on the application of ultrasound in the perioperative period of CEA and CAS was reviewed through the databases of CNKI, Pubmed, and Web of Science.

RESULTS

Ultrasound has high clinical value in preoperative screening for indications, assessing the degree of carotid artery stenosis and the nature of plaque; monitoring hemodynamic changes intraoperatively to prevent cerebral ischemia or overperfusion; and evaluating surgical outcomes postoperatively and in late follow-up review.

CONCLUSION

Ultrasound is currently widely used perioperatively in CEA and CAS and has even become the preferred choice of clinicians to evaluate the efficacy of surgery and follow-up. The presence of vulnerable plaque is an important risk factor for ischemic stroke. Contrast-enhanced ultrasound is an excellent tool to assess plaque stability. In most studies, ultrasound has been used only in a short follow-up period after CEA and CAS, and data from longer follow-ups are needed to provide more reliable evidence.

Carotid plaque score and ischemic stroke risk stratification through a combination of B-mode and contrast-enhanced ultrasound in patients with low and intermediate carotid stenosis

Objective

The occurrence of ischemic stroke (IS) is closely related to the characteristics of carotid plaque (CP). Due to the effect of stroke risk stratification based on B-mode ultrasound (US) and contrast-enhanced ultrasound (CEUS) that has not been studied in patients with low and intermediate carotid stenosis, we construct and validate a CP score and ischemic stroke risk stratification (ISRS) using a combination of B-mode and CEUS, in order to provide new convenient strategies to stratify these patients to prevent stroke.

Materials and methods

This retrospective study evaluated 705 patients with low and intermediate carotid stenosis who underwent B-mode and CEUS from November 2021 to April 2023. Qualitative B-mode and CEUS features of carotid plaques were analyzed using a univariable and multivariable logistic regression to construct the CP score. Then, we combined the CP score with Essen stroke risk score (ESRS) to develop ISRS.

Results

This study included a total of 705 patients with low and intermediate carotid stenosis, of which 394 were symptomatic patients (with a mean age of 71.03 ± 10.48 years) and 311 were asymptomatic patients (with a mean age of 65.13 ± 10.31 years). Plaque echogenicity, plaque morphology, carotid intima-media thickness in B-mode US and intraplaque neovascularization grading and perfusion pattern in CEUS were significantly associated with IS. The ISRS incorporating these five predictors and ESRS showed good discrimination and calibration in both primary cohort [area under the curve (AUC), 0.91; Hosmer-Lemeshow test, p = 0.903] and validation cohort (AUC, 0.84; Hosmer-Lemeshow test, p = 0.886).

Conclusion

We developed an effective and practical tool to identify and stratify patients with low and intermediate carotid stenosis, based on the CP score and ISRS estimation. Our study may provide new insights into managing patients with no indication of surgery.

Neovascularization From the Carotid Artery Lumen Into the Carotid Plaque Confirmed by Contrast-Enhanced Ultrasound and Histology

OBJECTIVE

This study was aimed at assessing intraplaque neovessels, focusing on neovascularization from the vascular luminal side using contrast-enhanced ultrasound (CEUS) and determining that this contrast effect indicates that the neovessel is connected to the vessel lumen histopathologically. Whether plaque vulnerability can be assessed more accurately was also investigated.

METHODS

We enrolled consecutive patients with internal carotid artery stenosis who underwent carotid endarterectomy (CEA) and pre-operative CEUS with perflubutane of the carotid arteries. We graded the contrast effect semi-quantitatively from the vascular luminal and adventitial sides. We compared the contrast effect with the pathological findings, especially the neovascularization of the CEA specimens.

RESULTS

In total, 68 carotid arterial atheromatous plaques (47 symptomatic) were analyzed. Symptomatic plaques were significantly correlated with stronger contrast effects from the luminal side than from the adventitial side (p = 0.0095). Microbubbles from the luminal side appeared to flow mainly into the plaque shoulder. The contrast effect value for the plaque shoulder and neovessel density were significantly correlated (ρ = 0.35, p = 0.031). Neovessel density was significantly higher in symptomatic than in asymptomatic plaques (56.2 ± 43.7/mm2 and 18.1 ± 15.2/mm2, respectively, p < 0.0001). Serial histological sections of CEA specimens in a symptomatic plaque with a strong contrast effect from the luminal side revealed multiple neovessels fenestrated to the vessel lumen with endothelial cells, consistent with the CEUS findings.

CONCLUSION

Contrast-enhanced ultrasound can be used to evaluate neovessels originating from the luminal side, histopathologically confirmed in serial sections. Symptomatic vulnerable plaque is correlated more significantly with intraplaque neovascularization from the luminal side than with neovascularization from the adventitia.

Novel ultrasound techniques in the identification of vulnerable plaques-an updated review of the literature

Atherosclerosis is an inflammatory disease partly mediated by lipoproteins. The rupture of vulnerable atherosclerotic plaques and thrombosis are major contributors to the development of acute cardiovascular events. Despite various advances in the treatment of atherosclerosis, there has been no satisfaction in the prevention and assessment of atherosclerotic vascular disease. The identification and classification of vulnerable plaques at an early stage as well as research of new treatments remain a challenge and the ultimate goal in the management of atherosclerosis and cardiovascular disease. The specific morphological features of vulnerable plaques, including intraplaque hemorrhage, large lipid necrotic cores, thin fibrous caps, inflammation, and neovascularisation, make it possible to identify and characterize plaques with a variety of invasive and non-invasive imaging techniques. Notably, the development of novel ultrasound techniques has introduced the traditional assessment of plaque echogenicity and luminal stenosis to a deeper assessment of plaque composition and the molecular field. This review will discuss the advantages and limitations of five currently available ultrasound imaging modalities for assessing plaque vulnerability, based on the biological characteristics of the vulnerable plaque, and their value in terms of clinical diagnosis, prognosis, and treatment efficacy assessment.

Associations of plaque morphology and location with Intraplaque neovascularization in the carotid artery by contrast-enhanced ultrasound imaging

Objective

Intraplaque neovascularization (IPN) is a known indicator of plaque vulnerability, and is thus considered a predictor of stroke. The morphology and location of the carotid plaque may be correlated with plaque vulnerability. Therefore, our study aimed to examine the associations of carotid plaque morphology and location with IPN.

Methods

A total of 141 patients with carotid atherosclerosis (mean age, 64.99 ± 10.96 years) who underwent carotid contrast-enhanced ultrasound (CEUS) between November 2021 and March 2022 were retrospectively analyzed. IPN was graded according to the presence and location of microbubbles within the plaque. The association of IPN grade with carotid plaque morphology and location was evaluated using ordered logistic regression.

Results

Of the 171 plaques, 89 (52%) were IPN Grade 0, 21 (12.2%) were Grade 1, and 61 (35.6%) were Grade 2. IPN grade significantly associated with both plaque morphology and location, with higher grades observed among Type III morphology and common carotid artery plaques. Significant negative association was further shown between IPN grade and serum high-density lipoprotein cholesterol (HDL-C) level. Plaque morphology and location, and HDL-C remained significantly associated with IPN grade after adjusting for confounding factors.

Conclusion

The location and morphology of carotid plaques were significantly associated with the IPN grade on CEUS, and therefore show potential as biomarkers for plaque vulnerability. Serum HDL-C was also identified as a protective factor against IPN, and may play a role in the management of carotid atherosclerosis. Our study provided a potential strategy for identification of vulnerable carotid plaques and elucidated the important imaging predictors of stroke.

Contrast-Enhanced Ultrasound Combined With 2D Strain Imaging and Histopathological Multimodal Assessment of Carotid Plaque Vulnerability

OBJECTIVE

The aim of this study was to explore the value of contrast-enhanced ultrasound (CEUS) combined with 2-D strain imaging in evaluating carotid plaque vulnerability and the correlations among CEUS perfusion parameters, strain parameters and histopathological findings in different plaque segments.

METHODS

Patients with carotid artery stenosis who underwent carotid endarterectomy (CEA) at the First Affiliated Hospital of Xinjiang Medical University from September 2020 to June 2021 underwent preoperative carotid artery 2-D ultrasonography and CEUS. The plaques were divided into three segments: the proximal end of the shoulder, central cap and distal end of the shoulder. The peak intensity (PI) value and strain rate parameters of the regions of interest were analyzed. Plaques were divided into a stable group (8 cases) and an unstable group (19 cases). The microvascular density (MVD) and vascular endothelial growth factor (VEGF) expression of each patch in the unstable group were analyzed.

RESULTS

The peak strain during the systolic period in each plaque segment in both groups showed the following pattern: proximal end shoulder > distal end shoulder > top (p < 0.05). The PI value for CEUS is also represented. In the unstable group, the PI values of each segment of the plaque were positively correlated with the MVD, near-center PI value and VEGF average optical density value. The average optical density of each segment was positively correlated with the MVD (p < 0.05). There were positive correlations between the PI values of the proximal and distal shoulder and the strain values (p < 0.05), and the MVD value of each segment, VEGF value and strain value were positively correlated (p < 0.05).

CONCLUSION

PI and the pathological tissue components represented by CEUS were positively correlated with the mechanical parameters of the plaque along the long axis. There may be overlap between the high shear stress area of the plaque and the neovascular aggregation area, and the combination of the two has certain significance for assessing the vulnerability of the plaque.

Evaluation of carotid plaque vulnerability with different echoes by shear wave elastography and CEUS

OBJECTIVE

Using shear wave elastography (SWE) and contrast enhanced ultrasound (CEUS)to examine carotid plaques with different echoes, and explore a reliable method to quantify characteristics associated with vulnerable carotid plaques.

METHODS

2D ultrasound, SWE and CEUS were performed on 244 carotid plaques, and the echoes were evaluated according to the Gray-Weale classification scale and gray-scale median (GSM), and the mean Young's modulus (YM) of the plaque was measured and the intraplaque neovascularization was observed to investigate the relationship between carotid plaque types with different echo characteristics, GSM and the values of each parameter of YM and CEUS. The relationship between GSM and YM and CEUS values was investigated.

RESULTS

The differences between GSM values (F = 49.742, P < 0.001), with the maximum, mean, and minimum YM values of ultrasound elastography (P < 0.001), and with the number (P < 0.001) and density (P = 0.047) of neovascularization on CEUS were statistically significant for the different echogenic types of plaques, and the lower the echogenicity of the plaque, the lower the GSM values (r = 0.632, P < 0.001), the smaller the YM values (all r > 0, P < 0.001), and the higher the neovascularization number and density values (r < 0, P < 0.001); and there were also statistically significant differences between the above indicators in the vulnerable and stable plaque groups (all P < 0.05).

CONCLUSION

GSM, SWE, and CEUS techniques can quantitatively evaluate the vulnerability of different echo carotid plaques in a more comprehensive and objective manner, which may help clinical identification of vulnerable plaques, and provide important reference values for early diagnosis and treatment in clinical practice.

The Value of Superb Microvascular Imaging and Contrast-enhanced Ultrasound for the Evaluation of Neovascularization in Carotid Artery Plaques

OBJECTIVE

To compare the consistency between superb microvascular imaging (SMI) and contrast-enhanced ultrasound (CEUS) for the detection of neovascularization in carotid plaques of different thicknesses and to evaluate the applied value of these two methods for detecting neovascularization in carotid plaques in the clinic.

METHODS

A total of 45 patients with carotid artery plaques who were diagnosed in our hospital involving 76 hypoechoic plaques with a thickness ≥2.0 mm were selected. According to thickness, the plaques were divided into three groups: 2.0-2.5 mm, 2.5-3.0 mm and ≥3.0 mm. Each group underwent both SMI and CEUS, and two experienced sonographers (A and B) analyzed the ultrasound images to evaluate the neovascularization of carotid plaques. The amount of the neovascular signal was assessed using a semi-quantitative grading scale (vascularity grade: grade 0-3). SMI and CEUS were graded respectively according to the visual methods as follows: grade 0: no blood flow signal/enhancement within plaques; grade 1: a few blood flow signals/enhancement within plaques; grade 2: medium blood flow signals/enhancement within plaques; and grade 3: extensive blood flow signals/enhancement within plaques. Kappa consistency test was used to analyze the consistency of the grade of neovascularization in plaques between SMI with CEUS. Gamma rank correlation analysis was used to examine the correlation between neovascularization grade by SMI and CEUS in plaque and plaque thickness.

RESULTS

Of these patients, 14 had unilateral plaques and 31 had bilateral plaques. The two sonographers were highly consistent in terms of applying SMI and CEUS methods for diagnosing neovascularization in carotid plaques (Kappa values were 0.736 and 0.680>0). Consistency was found between SMI and CEUS by sonographers (sonographer A: Kappa=0.823; sonographer B: Kappa=0.842) in evaluating the neovascular grade in the carotid plaques. SMI and CEUS grades were positively correlated with plaque thickness (sonographer A: γ = 0.735 and 0.772; sonographer B: γ = 0.805 and 0.798).

CONCLUSION

Neovascularization in carotid plaques was successfully detected by SMI in a manner that concurred well with CEUS results. Our data indicate that both CEUS and SMI have high diagnostic value for assessing the neovascularization of plaques.

Value of Intraplaque Neovascularization on Contrast-Enhanced Ultrasonography in Predicting Ischemic Stroke Recurrence in Patients With Carotid Atherosclerotic Plaque

OBJECTIVE

Patients with a history of ischemic stroke are at risk for a second ischemic stroke. This study aimed to investigate the relationship between carotid plaque enhancement on perfluorobutane microbubble contrast-enhanced ultrasonography (CEUS) and future recurrent stroke, and to determine whether plaque enhancement can contribute to risk assessment for recurrent stroke compared with the Essen Stroke Risk Score (ESRS).

MATERIALS AND METHODS

This prospective study screened 151 patients with recent ischemic stroke and carotid atherosclerotic plaques at our hospital between August 2020 and December 2020. A total of 149 eligible patients underwent carotid CEUS, and 130 patients who were followed up for 15-27 months or until stroke recurrence were analyzed. Plaque enhancement on CEUS was investigated as a possible risk factor for stroke recurrence and as a possible adjunct to ESRS.

RESULTS

During follow-up, 25 patients (19.2%) experienced recurrent stroke. Patients with plaque enhancement on CEUS had an increased risk of stroke recurrence events (22/73, 30.1%) compared to those without plaque enhancement (3/57, 5.3%), with an adjusted hazard ratio (HR) of 38.264 (95% confidence interval [CI]:14.975-97.767; P < 0.001) according to a multivariable Cox proportional hazards model analysis, indicating that the presence of carotid plaque enhancement was a significant independent predictor of recurrent stroke. When plaque enhancement was added to the ESRS, the HR for stroke recurrence in the high-risk group compared to that in the low-risk group (2.188; 95% CI, 0.025-3.388) was greater than that of the ESRS alone (1.706; 95% CI, 0.810-9.014). A net of 32.0% of the recurrence group was reclassified upward appropriately by the addition of plaque enhancement to the ESRS.

CONCLUSION

Carotid plaque enhancement was a significant and independent predictor of stroke recurrence in patients with ischemic stroke. Furthermore, the addition of plaque enhancement improved the risk stratification capability of the ESRS.

Diagnostic Performance of Contrast-Enhanced Ultrasound and High-Resolution Magnetic Resonance Imaging for Carotid Atherosclerotic Plaques: A Systematic Review and Meta-Analysis

OBJECTIVES

The aim of this meta-analysis was to evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) and high-resolution magnetic resonance imaging (HR-MRI) in patients with carotid vulnerable plaques.

METHODS

A systematic review was conducted in PubMed, Embase, Cochrane Library, and Web of Science using the search terms carotid artery, atherosclerotic plaque, CEUS, contrast-enhanced ultrasound, HR-MRI, and high-resolution magnetic resonance. Studies published since the establishment of the library until December 2021 were retrieved. The statistical analyses were performed with Meta-DiSc version 1.4. Beyond that, the potential sources of heterogeneity for CEUS and HR-MRI were explored.

RESULTS

Nine articles were included in this study. For CEUS, the pooled sensitivity and specificity for detecting carotid vulnerable plaques 91% (95% confidence interval [CI]: 84%, 95%) and 67% (95% CI: 54%, 79%), respectively. For HR-MRI, the pooled sensitivity and specificity were 78% (95% CI: 72%, 83%) and 65% (95% CI, 56%, 73%), respectively. The area under the summary receiver operating characteristic curve for CEUS and HR-MRI were 0.9218 and 0.8129, respectively. However, the difference in diagnostic accuracy between CEUS and HR-MRI diagnostic accuracy was not statistically significant.

CONCLUSIONS

The study shows that the sensitivity of CEUS was higher than that of HR-MRI, and the specificity was similar to HR-MRI. CEUS and HR-MRI provide a similar diagnostic yield in detecting a vulnerable plaque. Thus, CEUS may be a useful tool for the diagnosis of carotid vulnerable plaques.

Effect of evolocumab on the progression of intraplaque neovascularization of the carotid based on contrast-enhanced ultrasonography (EPIC study): A prospective single-arm, open-label study

Background and Purpose: The aim of this study was to explore the effect of half a year of evolocumab plus moderate-intensity statin treatment on carotid intraplaque neovascularization (IPN) and blood lipid levels. Methods: A total of 31 patients with 33 carotid plaques who received evolocumab plus statin treatment were included. Blood lipid levels, B-mode ultrasound and contrast-enhanced ultrasonography (CEUS) at baseline and after half a year of evolocumab plus statin therapy were collected. The area under the curve (AUC) reflected the total amount of acoustic developer entering the plaque or lumen within the 180 s measurement period. The enhanced intensity reflected the peak blood flow intensity during the monitoring period, and the contrast agent area reflected the area of vessels in the plaques. Results: Except for high-density lipoprotein cholesterol (HDL-c), all other lipid indices decreased. Compared with baseline, low-density lipoprotein cholesterol (LDL-c) decreased by approximately 57% (p < 0.001); total cholesterol (TC) decreased by approximately 34% (p < 0.001); small dense low-density lipoprotein (sd-LDL) decreased by approximately 52% (p < 0.001); and HDL-c increased by approximately 20% (p < 0.001). B-mode ultrasonography showed that the length and thickness of the plaque and the hypoechoic area ratio were reduced (p < 0.05). The plaque area, calcified area ratio, and lumen cross-sectional area changed little (p > 0.05). CEUS revealed that the area under the curve of plaque/lumen [AUC (P/L)] decreased from 0.27 ± 0.13 to 0.19 ± 0.11 (p < 0.001). The enhanced intensity ratio of plaque/lumen [intensity ratio (P/L)] decreased from 0.37 ± 0.16 to 0.31 ± 0.14 (p = 0.009). The contrast agent area in plaque/area of plaque decreased from 19.20 ± 13.23 to 12.66 ± 9.59 (p = 0.003). The neovascularization score decreased from 2.64 ± 0.54 to 2.06 ± 0.86 (p < 0.001). Subgroup analysis based on statin duration (<6 months and ≥6 months) showed that there was no significant difference in the AUC (P/L) or intensity ratio (P/L) at baseline or after half a year of evolocumab treatment. Conclusion: This study found that evolocumab combined with moderate-intensity statins significantly improved the blood lipid profile and reduced carotid IPN. Clinical Trial Registration: https://www.clinicaltrials.gov; identifier: NCT04423406.

Advances in Noninvasive Carotid Wall Imaging with Ultrasound: A Narrative Review

Carotid atherosclerosis is a major cause for stroke, with significant associated disease burden morbidity and mortality in Western societies. Diagnosis, grading and follow-up of carotid atherosclerotic disease relies on imaging, specifically ultrasound (US) as the initial modality of choice. Traditionally, the degree of carotid lumen stenosis was considered the sole risk factor to predict brain ischemia. However, modern research has shown that a variety of other imaging biomarkers, such as plaque echogenicity, surface morphology, intraplaque neovascularization and vasa vasorum contribute to the risk for rupture of carotid atheromas with subsequent cerebrovascular events. Furthermore, the majority of embolic strokes of undetermined origin are probably arteriogenic and are associated with nonstenosing atheromas. Therefore, a state-of-the-art US scan of the carotid arteries should take advantage of recent technical developments and should provide detailed information about potential thrombogenic (/) and emboligenic arterial wall features. This manuscript reviews recent advances in ultrasonographic assessment of vulnerable carotid atherosclerotic plaques and highlights the fields of future development in multiparametric arterial wall imaging, in an attempt to convey the most important take-home messages for clinicians performing carotid ultrasound.

Early Assessment of Atherosclerotic Lesions and Vulnerable Plaques in vivo by Targeting Apoptotic Macrophages with AV Nanobubbles

Background

The early detection of atherosclerotic lesions is particularly important for risk prediction of acute cardiovascular events. Macrophages apoptosis was significantly associated with the degree of AS lesions and especially contributed to plaque vulnerability. In this research, we mainly sought to explore the feasibility of a home-made AV-nanobubbles (NB_AV) for visualization of apoptotic macrophages and assessment of atherosclerosis (AS) lesions by contrast-enhanced ultrasound (CEUS) imaging.

Methods

NB_AV were prepared by “Optimized Thin-Film Hydration” and “Biotin-Avidin-Biotin” methods. Then, the characterization and echogenicity of NB_AV were measured and analyzed in vitro. The targeting ability of NB_AV to ox-LDL–induced apoptotic macrophages was observed by laser scanning confocal microscope. The ApoE^−/− mice mode fed with high fat diet were observed by high-frequency ultrasound, microanatomy and oil red O staining. CEUS imaging in vivo was performed on AS plaques with NB_AV and NB_Ctrl injection through the tail vein in turn in ApoE^−/− mice. After CEUS imaging, the plaques were confirmed and analyzed by histopathological and immunological assessment.

Results

The prepared NB_AV had a nano-scale size distribution with a low PDI and a negative zeta potential. Moreover, NB_AV showed an excellent stability and exhibited a significantly echogenic signal than saline in vitro. In addition, we found that NB_AV could target apoptotic macrophages induced by ox-LDL. Compared with NB_Ctrl, CEUS imaging of NB_AV showed strong and sustained echo enhancement in plaque area of aortic arch in vivo. Further research showed that NB_AV sensitive plaques presented more significant pathological changes with several vulnerable plaque features and abundant TUNEL-positive area.

Conclusion

NB_AV displayed a sensitive indicator to evaluate apoptotic macrophages, indicating a promising CEUS molecular probe for AS lesions and vulnerable plaques identification.

High systemic immune-inflammation index is associated with carotid plaque vulnerability: New findings based on carotid ultrasound imaging in patients with acute ischemic stroke

Vulnerable carotid plaque is closely related to the occurrence of Ischemic stroke. Therefore, accurate and rapid identification of the nature of carotid plaques is essential. AS is a chronic immune inflammatory process. Systemic immune-inflammation index (SII) is a novel index of immune inflammation obtained from routine whole blood cell count analysis, which comprehensively reflects the state of inflammation and immune balance in the body. This study sought to explore the relationship between SII level and carotid plaque vulnerability, plaque composition characteristics, and acute ischemic stroke (AIS) severity. A total of 131 patients diagnosed with AIS presenting with a carotid atherosclerotic plaque were enrolled in this study. Using carotid ultrasound (CDU) to assess the carotid-responsible plaque properties, we divided the patients into stable plaques group and vulnerable plaques group, and analyzed the correlation between SII levels and plaque vulnerability. And we further analyzed to evaluate the correlation between high SII levels and plaque characteristics and AIS severity. In addition, Cohen's Kappa statistics was used to detect the consistency of Carotid ultrasound (US) and cervical High-resolution magnetic resonance imaging (HRMRI) in evaluating plaque vulnerability. The findings showed that the vulnerable group had higher levels of SII compared with the stable group. The high SII group had more vulnerable plaques and a high frequency of plaque fibrous cap rupture compared with the low SII group. Logistic analysis showed that a high SII level was an independent risk factor for vulnerable plaques (odds ratio [OR] = 2.242) and plaque fibrous cap rupture (OR=3.462). The results also showed a high consistency between Carotid US and HRMRI methods in the assessment of plaque vulnerability [Cohen's kappa value was 0.89 (95% CI = 0.78-0.97)] and the level of SII was positively associated with NIHSS score (r = 0.473, P < 0.001). Our study suggests that elevated levels of SII may have adverse effects on the vulnerability of carotid plaques, especially in stroke patients with vulnerable plaques with ruptured fibrous caps, which may aggravate the severity of AIS.

Three-Dimensional High-Resolution Magnetic Resonance Imaging for the Assessment of Cervical Artery Dissection

Background and Purpose

Diagnosing cervical artery dissection (CAD) is still a challenge based on the current radiographic criteria. This study aimed to assess the value of three-dimensional high-resolution magnetic resonance imaging (3D HRMRI) in the detection of the signs of CAD and its diagnosis.

Materials and Methods

Patients with CAD from January 2016 to January 2021 were recruited from our 3D HRMRI database. The signs of dissection (intramural hematomas, intimal flap, double lumen), length and location of the dissection, thickness of the intramural hematoma, intraluminal thrombus, and percentage of dilation of the outer contour of the dissection on 3D HRMRI were assessed.

Results

Fourteen patients with 16 CADs, including 12 carotid CADs and 4 vertebral CADs, were finally diagnosed in this study. On 3D HRMRI, intramural hematomas were detected in 13/16 (81.3%) lesions with high sensitivity (100%) and high specificity (100%). Intimal flaps were found in 9/16 (56.3%) lesions with moderate sensitivity (64.3%) and high specificity (88.9%). Double lumen signs were observed in 4/16 (25.0%) lesions with high sensitivity (80.0%) and high specificity (100%). In addition, concomitant intraluminal thrombus were detected in 4/16 (25.0%) lesions with high sensitivity (80.0%) and high specificity (100%). The mean length of dissection was (25.1 ± 13.7) mm. The mean thickness of the intramural hematoma was (4.3 ± 2.3) mm. The mean percentage of dilation for the outer contour of the dissection was (151.3 ± 28.6)%.

Conclusion

The 3D HRMRI enables detection of the dissecting signs, such as intramural hematoma, intimal flap, double lumen, and intraluminal thrombus with high sensitivity and specificity, suggesting a useful, and non-invasive tool for definitively diagnosing CAD.

Texture Analysis Based on Vascular Ultrasound to Identify the Vulnerable Carotid Plaques

Vulnerable carotid plaques are closely related to the occurrence of ischemic stroke. Therefore, accurate and rapid identification of the nature of carotid plaques is essential. This study aimed to determine whether texture analysis based on a vascular ultrasound can be applied to identify vulnerable plaques. Data from a total of 150 patients diagnosed with atherosclerotic plaque (AP) by carotid ultrasound (CDU) and high-resolution magnetic resonance imaging (HRMRI) were collected. HRMRI is the in vivo reference to assess the nature of AP. MaZda software was used to delineate the region of interest and extract 303 texture features from ultrasonic images of plaques. Following regression analysis using the least absolute shrinkage and selection operator (LASSO) algorithm, the overall cohort was randomized 7:3 into the training (n = 105) and testing (n = 45) sets. In the training set, the conventional ultrasound model, the texture feature model, and the conventional ultrasound-texture feature combined model were constructed. The testing set was used to validate the model’s effectiveness by calculating the area under the curve (AUC), accuracy, sensitivity, and specificity. Based on the combined model, a nomogram risk prediction model was established, and the consistency index (C-index) and the calibration curve were obtained. In the training and testing sets, the AUC of the prediction performance of the conventional ultrasonic-texture feature combined model was higher than that of the conventional ultrasonic model and the texture feature model. In the training set, the AUC of the combined model was 0.88, while in the testing set, AUC was 0.87. In addition, the C-index results were also favorable (0.89 in the training set and 0.84 in the testing set). Furthermore, the calibration curve was close to the ideal curve, indicating the accuracy of the nomogram. This study proves the performance of vascular ultrasound-based texture analysis in identifying the vulnerable carotid plaques. Texture feature extraction combined with CDU sonogram features can accurately predict the vulnerability of AP.

Diagnostic Performance of Atherosclerotic Carotid Plaque Neovascularization with Contrast-Enhanced Ultrasound: A Meta-Analysis

Objectives

To evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) for atherosclerotic carotid plaque neovascularization.

Methods

The electronic databases like PubMed, Embase, OVID, and Web of Science were used to search for the relevant studies, which are involved in the evaluation of the diagnostic parameters of QUS for atherosclerotic carotid plaque neovascularization. Review Manager 5.4 and Stata 14.0 were used to estimate the pooled diagnostic value of CEUS. Forest plots, sensitivity analysis, and Deeks' funnel plots were performed on the included studies.

Results

Ten studies eventually met the final inclusion criteria. For diagnostic performance, CUES showed that the pooled values of sensitivity, specificity, positive likelihood odds ratios, negative likelihood odds ratios, and diagnostic odds ratios were 0.83 (95% CI 0.78-0.86), 0.77 (95% CI 0.68-0.84), 3.61 (95% CI 2.59-5.03), 0.23 (95% CI 0.18-0.28), and 16.02 (95% CI 10.02-25.60), respectively. The estimate of the area under curve (AUC) was 0.85 (95% CI 0.82-0.88).

Conclusion

Our research supported that CEUS had high sensitivity and specificity in the diagnosis of atherosclerotic carotid plaque neovascularization. More high-quality prospective multicenter studies focusing on the accuracy of CEUS for carotid atherosclerotic plaque should be performed to verify our conclusions.

Low-Intensity Focused Ultrasound-Responsive Ferrite-Encapsulated Nanoparticles for Atherosclerotic Plaque Neovascularization Theranostics

Pathological angiogenesis is a crucial factor that causes atherosclerotic plaque rupture. Sinoporphyrin sodium-mediated sonodynamic therapy (DVDMS-SDT) induces regression of plaque neovascularization in humans without causing obvious side effects. However, a clinical noninvasive theranostic strategy for atherosclerotic plaque neovascularization is urgently needed. A nanoplatform designed for multimodality imaging-guided SDT in plaque angiogenesis theranostics, termed PFP-HMME@PLGA/MnFe2 O4 -ramucirumab nanoparticles (PHPMR NPs), is fabricated. It encapsulates manganese ferrite (MnFe2 O4 ), hematoporphyrin monomethyl ether (HMME), and perfluoropentane (PFP) stabilized by polylactic acid-glycolic acid (PLGA) shells and is conjugated to an anti-VEGFR-2 antibody. With excellent magnetic resonance imaging (MRI)/photoacoustic/ultrasound imaging ability, the distribution of PHPMR NPs in plaque can be observed in real time. Additionally, they actively accumulate in the mitochondria of rabbit aortic endothelial cells (RAECs), and the PHPMR NP-mediated SDT promotes mitochondrial-caspase apoptosis via the production of reactive oxygen species and inhibits the proliferation, migration, and tubulogenesis of RAECs. On day 3, PHPMR NP-mediated SDT induces apoptosis in neovessel endothelial cells and improves hypoxia in the rabbit advanced plaque. On day 28, PHPMR NP-mediated SDT reduces the density of neovessels, subsequently inhibiting intraplaque hemorrhage and inflammation and eventually stabilizing the plaque. Collectively, PHPMR NP-mediated SDT presents a safe and effective theranostic strategy for inhibiting plaque angiogenesis.

A narrative review of the pathophysiology of ischemic stroke in carotid plaques: a distinction versus a compromise between hemodynamic and embolic mechanism

Atherosclerotic carotid artery stenosis causes about 10–20% of all ischemic strokes through two main mechanisms: hemodynamic impairment in case of significant stenosis and thromboembolism from an atherosclerotic plaque regardless of the degree of stenosis. The latter is the most frequent mechanism and appear to result from embolization from a vulnerable atherosclerotic plaque or acute occlusion of the carotid artery and propagation of thrombus distally. Downstream infarcts may occur in a territory of major cerebral artery or at the most distal areas between two territories of major cerebral arteries, the so-called watershed (WS), or border zone area. Although WS infarcts, especially deep WS infarct, were historically thought to be due to hemodynamic compromise, the role of microembolism has also been documented, both mechanisms may act synergistically to promote WS infarcts. Routine and more advanced imaging techniques may provide information on the underlying mechanism involved in ipsilateral ischemic stroke. A better understanding of ischemic stroke pathogenesis in carotid stenosis may limit the use of routine non-selective shunt, whose benefit-risk balance is debated, to patients with hemodynamic impairment.

After reviewing existing evidence underpinning the contribution of the two mechanisms in downstream ischemic stroke and the various imaging techniques available to investigate them, we will focus on the pathogenesis of WS infarcts that remains debated.

Ferrite-encapsulated nanoparticles with stable photothermal performance for multimodal imaging-guided atherosclerotic plaque neovascularization therapy

Pathological angiogenesis is a critical contributor to atherosclerotic plaque rupture. However, there are few effective theranostic strategies to stabilize plaques by suppressing neovascularization. In this study, we fabricated a polymeric nanosystem using 3 nm manganese ferrite (MnFe₂O₄) and perfluorohexane (PFH) stabilized by polylactic acid-glycolic acid (PLGA) shells and conjugated to the surface of an anti-vascular endothelial growth factor receptor 2 (VEGFR2) antibody [ramucirumab (Ram)]. The PFH@PLGA/MnFe₂O₄-Ram nanoparticles (NPs) were used as atherosclerotic plaque angiogenesis theranostics for multimodal imaging-guided photothermal therapy (PTT). Three-nanometer MnFe₂O₄ is an excellent magnetic resonance imaging T1 and photoacoustic imaging contrast agent. Upon exposure to near-infrared (NIR) light, MnFe₂O₄ in the NPs could transform NIR light into thermal energy for the photothermal elimination of plaque angiogenesis. Additionally, optical droplet vaporization of PFH in the NPs triggered by the thermal effect to form gas bubbles enhanced ultrasound imaging. Our in vitro experiments revealed that PFH@PLGA/MnFe₂O₄-Ram NPs actively accumulated in rabbit aortic endothelial cells, and NP-mediated PTT promoted endothelial cell apoptosis while inhibiting their proliferation, migration, and tubulogenesis. Notably, the PFH@PLGA/MnFe₂O₄-Ram NPs possessed excellent photostability and biocompatibility. In the rabbit advanced atherosclerotic plaque model, PFH@PLGA/MnFe₂O₄-Ram NP-guided PTT significantly induced apoptosis of neovascular endothelial cells and improved the hypoxia status in the plaque 3 days after treatment. On day 28, PTT significantly reduced the density of neovessels and subsequently stabilized rabbit plaques by inhibiting plaque hemorrhage and macrophage infiltration. Collectively, these results suggest that PFH@PLGA/MnFe₂O₄-Ram NP-guided PTT is a safe and effective theranostic strategy for inhibiting atherosclerotic plaque angiogenesis.

Carotid intraplaque neovascularisation as a predictive factor for future vascular events in patients with mild and moderate carotid stenosis: an observational prospective study

Background:

Intraplaque neovascularisation (IPN) increases the vulnerability of plaques, which makes them more likely to rupture and increases the risk of vascular events. However, it is unclear whether IPN can predict future vascular events (stroke recurrence and cardiovascular events). Previous studies on IPN have focused on patients with severe stenosis but overlooked patients with mild and moderate stenosis. This study aimed to investigate whether IPN assessed by contrast-enhanced ultrasonography (CEUS) in patients with mild and moderate degrees of stenosis is associated with future vascular events.

Methods:

One hundred and twenty-one patients participated in this study. 76 patients who met the inclusion and exclusion criteria were included in the final dataset of the study. IPN was graded from 0 to 2 according to the extent of the microbubbles assessed using CEUS. The degree of carotid stenosis was graded as mild, moderate, or severe. We recorded future vascular events during the follow-up. Univariate and multivariate logistic regression analyses were used to evaluate risk factors for future vascular events.

Results:

After a follow-up period of 30 ± 6 months, 30 patients (39.5%) experienced subsequent vascular events. Compared with the ‘non-recurrent’ group, the ‘recurrent’ group showed a higher proportion of grade 2 neovascularisation (p < 0.05), and it was an independent predictor of subsequent vascular events (odds ratio 6.066, 95% confidence interval 1.565–23.512, p < 0.05). Furthermore, in patients with mild and moderate stenosis, future vascular events occurred in an unexpectedly high proportion (up to 42.9%). In the ‘recurrent’ group, 55% of patients with mild and moderate stenosis had grade 2 neovascularisation.

Conclusion:

IPN by CEUS was an independent predictor of future vascular events in patients with recent ischemic stroke, and the high proportion of neovascularisation in patients with mild and moderate stenosis requires more attention.