A method of ultrasonic simulation based on the FIELD II software platform for carotid artery plaque was proposed according to the analysis for geometrical shape, tissue characteristics and acoustic properties of carotid artery plaques in clinic, and then a simulation system was developed by using the MATLAB graphical user interface (GUI). In the simulation and development, a three-dimensional geometric model of blood vessel with plaques was set up by using the metaball implicit surface technique, and a tissue model was established based on the scatterers with spatial position of gamma random distribution. Comparison of the statistical and geometrical characteristics from simulated ultrasound B-mode images with those based on clinical ones and preset values, the results fully demonstrated the effectiveness of the simulation methods and system.
Atherosclerotic plaque rupture is the main cause of many cardiovascular diseases, and biomechanical factors play an important role in the process of plaque rupture. In the study of plaque biomechanics, there are relatively few studies based on fatigue fracture failure theory, and most of them mainly focus on the whole fatigue propagation process from crack initiation to plaque rupture, while there are few studies on the influence of crack on plaque rupture at a certain time in the process of fatigue propagation. In this paper, a two-dimensional plaque model with crack was established. Based on the theory of fracture mechanics and combined with the finite element numerical simulation method, the stress intensity factor (SIF) and related influencing factors at the crack tip in the plaque were studied. The SIF was used to measure the influence of crack on plaque rupture. The results show that the existence of crack can lead to local stress concentration, which increases the risk of plaque rupture. The SIF at the crack tip in the plaque was positively correlated with blood pressure, but negatively correlated with fibrous cap thickness and lipid pool stiffness. The effect of the thickness and angle of lipid pool on the SIF at the crack tip in the plaque was less than 4%, which could be ignored. This study provides a theoretical basis for the risk assessment of plaque rupture with cracks.
Atherosclerosis is a complex and multi-factorial pathophysiological process. Researches over the past decades have shown that the development of atherosclerotic vulnerable plaque is closely related to its components, morphology, and stress status. Biomechanical models have been developed by combining with medical imaging, biological experiments, and mechanical analysis, to study and analyze the biomechanical factors related to plaque vulnerability. Numerical simulation could quantify the dynamic changes of the microenvironment within the plaque, providing a method to represent the distribution of cellular and acellular components within the plaque microenvironment and to explore the interaction of lipid deposition, inflammation, angiogenesis, and other processes. Studying the pathological mechanism of plaque development would improve our understanding of cardiovascular disease and assist non-invasive inspection and early diagnosis of vulnerable plaques. The biomechanical models and numerical methods may serve as a theoretical support for designing and optimizing treatment strategies for vulnerable atherosclerosis.
ObjectiveTo study the correlation between neck artery vascular sclerosis and homocysteine levels in hypertensive patients. MethodsA total of 2 132 patients with hypertension participated in the program of "Stroke screening and prevention in Dongying city" were included from Sep. 2012 to Jan. 2013. Questionnaire, physical examination, biochemical blood tests and carotid artery ultrasound were conducted in all included patients. According to the level of homocysteine (Hcy), patients were divided into three groups:716 patients with Hcy level less than 12.3 mm/L were in Group 1, 703 patients with Hcy level 12.3 to 16.5 mm/L were in Group 2, and 713 patients with Hcy level more than 16.5 mm/L were in Group 3. The influence of Hcy levels on carotid atherosclerosis was analyzed. Results① The prevalence rate for carotid plaques in Groups 1, 2, and 3 were 50.28%, 60.03% and 65.36%, respectively. The prevalence rate for carotid plaques in Group 2 was higher than that in Group 1 with a statistical difference (OR=1.485, 95% CI 1.203 to 1.833, P=0.000). The prevalence rate in Group 3 was also higher than that in Group 1 with a statistical difference (OR=1.866, 95% CI 1.508 to 2.308, P=0.000). ② The prevalence rate for carotid plaques was 62.24% in the rural population, and 52.39% in the urban population. The difference between urban and rural populations was statistically significant (OR=1.500, 95% CI 1.259 to 1.788, P=0.000). ③ Using the presence of carotid plaques as a dependent variable and Hcy level as a covariant, logistic regression analysis found that the plaque formation in Group 2 was 1.491 times than in Group 1 and the plaque formation in Group 3 was 1.752 times than in Group 1. After adjusting the risk factors (gender, age, BMI, TG, TC, LDL-C, HDL-C and blood sugar level), the results showed that the plaque formation in Group 2 was 1.388 times than in Group 1, and the plaque formation in Group 3 was 1.452 times than in Group 1. ConclusionThere is a correlation between the increased incidence of carotid plaque and homocysteine levels in patients with hypertension. The incidence of carotid plaque in the rural population with hypertension is higher than that in the urban population. In the population with hypertension, high homocysteine level is an independent risk factor for the formation of carotid plaques.
Intravascular ultrasound (IVUS) is widely used in coronary artery examination. Ultrasonic elastography combined with IVUS is very conspicuous in identifying plaque component and in detecting plaque vulnerability degree. In this study, a simulation model of the blood vessel based on finite element analysis (FEA) was established. The vessel walls generally have radial changes caused by different intravascular pressure. The signals at lower pressures were used as the pre-deformation data and the signals at higher pressure were used as the post-deformation data. Displacement distribution was constructed using the time-domain cross-correlation method, and then strain images. By comparison of elastograms under different pressures, we obtained the optimal pressure step. Furthermore, on the basis of the obtained optimize pressure step, the simulation results showed that this method could effectively distinguish characteristics between different component plaques, and could guide the later experiments and clinical applications.
Objective To construct a radiomics model for identifying clinical high-risk carotid plaques. Methods A retrospective analysis was conducted on patients with carotid artery stenosis in China-Japan Friendship Hospital from December 2016 to June 2022. The patients were classified as a clinical high-risk carotid plaque group and a clinical low-risk carotid plaque group according to the occurrence of stroke, transient ischemic attack and other cerebrovascular clinical symptoms within six months. Six machine learning models including eXtreme Gradient Boosting, support vector machine, Gaussian Naive Bayesian, logical regression, K-nearest neighbors and artificial neural network were established. We also constructed a joint predictive model combined with logistic regression analysis of clinical risk factors. ResultsFinally 652 patients were collected, including 427 males and 225 females, with an average age of 68.2 years. The results showed that the prediction ability of eXtreme Gradient Boosting was the best among the six machine learning models, and the area under the curve (AUC) in validation dataset was 0.751. At the same time, the AUC of eXtreme Gradient Boosting joint prediction model established by clinical data and carotid artery imaging data validation dataset was 0.823. Conclusion Radiomics features combined with clinical feature model can effectively identify clinical high-risk carotid plaques.
Objective To assess the efficacy and safety of efalizumab in the treatment of psoriasis. Methods Randomized controlled trials (RCT) on efalizumab in the treatment of psoriasis were identified from The Cochrane Library ( issue 1, 2006) , specialized trials registered in Cochrane Skin Group (2006), MEDLINE (1966 - 2006) and EMBASE (1974 - 2006). The quality of the trials was assessed by two reviewers independently. RevMan 4.2.7 software provided by the Cochrane Collaboration was used for statistical analysis. Results Three RCTs involving 1 651 patients were included, all of which were of high methodological quality. All the patients were diagnosed as chronic moderate to severe plaque psoriasis with the age of 18-75 years. Meta-analysis indicated that at week 12, significantly more patients in both 1mg/kg/w and 2 mg/kg/w efalizumab subcutaneous groups achieved PASI50, PASI75, PASI90 improvement compared to the placebo group (Plt;0.0001), while there was no significant difference in PASI50, PASI75 and PASI90 responses between 1mg and 2mg efalizumab groups (P gt;0.05). No serious adverse effects were identified. Extended treatment for another 12w may contribute to further efficacy without increasing toxicty. Conclusions Efalizumab 12w therapy is safe and effective for treating adult patients with moderate to severe plaque psoriasis. More RCTs are required to assess the efficacy of the extended treatment.
The segmentation of the intracoronary optical coherence tomography (OCT) images is the basis of the plaque recognition, and it is important to the following plaque feature analysis, vulnerable plaque recognition and further coronary disease aided diagnosis. This paper proposes an algorithm about multi region plaque segmentation based on kernel graph cuts model that realizes accurate segmentation of fibrous, calcium and lipid pool plaques in coronary OCT image, while boundary information has been well reserved. We segmented 20 coronary images with typical plaques in our experiment, and compared the plaque regions segmented by this algorithm to the plaque regions obtained by doctor's manual segmentation. The results showed that our algorithm is accurate to segment the plaque regions. This work has demonstrated that it can be used for reducing doctors' working time on segmenting plaque significantly, reduce subjectivity and differences between different doctors, assist clinician's diagnosis and treatment of coronary artery disease.
ObjectiveTo systematically review the long-term efficacy of biologics for moderate to severe plaque psoriasis. MethodsPubMed, EMbase, Web of Science and The Cochrane Library were electronically searched to collect randomized controlled trials (RCTs) on the long-term efficacy of approved biologics for moderate to severe plaque psoriasis from inception to May 2021. Two reviewers independently screened the literature, extracted data and assessed the risk of bias of the included studies; then, the network meta-analysis was performed by using Stata 16.0 software. ResultsA total of 26 RCTs were included. The results of network meta-analysis showed that among 11 biologics, the most effective biologics were risankizumab, followed by bimekizumab, brodalumab, guselkumab, and ixekizumab, and followed by secukinumab, adalimumab, ustekinumab, and etanercept was the last. ConclusionCurrent evidence shows that risankizumab is likely to be the best option for long-term treatment of moderate-to-severe plaque psoriasis. Due to the limited quality and quantity of the included studies, more high-quality studies are needed to verify the above conclusion.
In recent years, optical coherence tomography (OCT) has developed into a popular coronary imaging technology at home and abroad. The segmentation of plaque regions in coronary OCT images has great significance for vulnerable plaque recognition and research. In this paper, a new algorithm based on K-means clustering and improved random walk is proposed and Semi-automated segmentation of calcified plaque, fibrotic plaque and lipid pool was achieved. And the weight function of random walk is improved. The distance between the edges of pixels in the image and the seed points is added to the definition of the weight function. It increases the weak edge weights and prevent over-segmentation. Based on the above methods, the OCT images of 9 coronary atherosclerotic patients were selected for plaque segmentation. By contrasting the doctor’s manual segmentation results with this method, it was proved that this method had good robustness and accuracy. It is hoped that this method can be helpful for the clinical diagnosis of coronary heart disease.