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.
【摘要】 目的 探讨血尿酸水平、颈动脉斑块与冠心病之间的关系。 方法 收集2006年1月-2009年12月拟诊为冠心病的住院患者280例,冠状动脉造影检查冠状动脉狭窄程度gt;50%的194例为冠心病组,冠状动脉无狭窄或狭窄程度lt;50%的86例为对照组;冠心病组又分为单支、双支、多支病变亚组。分别测定冠心病组与对照组颈总动脉与颈动脉分叉处内膜中层厚度(IMT)、等级评分、Crouse积分、血尿酸浓度。结果 与对照组相比,冠心病组颈总动脉与颈动脉分叉处IMT、等级评分、Crouse积分、血尿酸浓度均高于对照组,差异有统计学意义。在冠心病组,随病变分支的增多,颈动脉超声检查指标与血尿酸随之升高(Plt;0.05或0.01)。 结论 颈动脉IMT、等级评分、Crouse积分、血尿酸浓度与冠心病相关,是冠心病的独立危险因素。【Abstract】 Objective To investigate the relationships between serum uric acid levels, carotid artery plaque and coronary heart disease (CHD). Methods 194 patients with CHD and 86 nonCHD patients were selected through coronary angiography in patients with essential hypertension. CHD group was divided into three subgroups including a single branch, doublebranch and multivessel disease. Intimamedia thickness (IMT) of carotid artery and carotid bifurcation, grade score, Crouse score, serum uric acid concentrations were detected in patients with coronary heart disease and control group. Results IMT of carotid artery and carotid bifurcation, grade score,crouse score, serum uric acid concentrations were higher in CHD group than that in control group, and the difference was statistically significant. In the CHD group, ultrasound parameters of carotid artery and serum uric acid increased with the increase in branch lesions (Plt;005 or 001). Conclusions Carotid IMT, grade score, Crouse score, serum uric acid concentration relate to coronary heart disease, which is an independent risk factor for coronary heart disease, respectively.
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.
The present paper intends to discuss the antioxidant and tyrosinase inhibition effect of solanesol from three aspects of ultraviolet radiation and free radical scavenging. The paper makes a survey on diurnal variation rule of the minimum ultraviolet transmittance and ultraviolet transmittance of solanesol, hydroxyl (·OH) free radical scavenging method of Smirnoff reaction system model, superoxide anion O2-· free radical scavenging method of pyrogallol autoxidation, and the inhibitory effect of solanesol on tyrosinase activity by enzyme kinetic method. The experiment results showed that solanesol could effectively scavenge lipid radicals to block lipid peroxidation, and inhibit effects on tyrosinase. Solanesol is a natural extract which could be used to prevent senile atrophy of human skin and senile plaque.
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.
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.
Optical coherence tomography (OCT) has become a key technique in the diagnosis of coronary artery stenosis, which can identify plaques and vulnerable plaques in the image. Therefore, this technique is of great significance for the diagnosis of coronary heart disease. However, there is still a lack of automatic, multi-region, high-precision segmentation algorithms for coronary OCT images in the current research field. Therefore, this paper proposes a multi-zone, fully automated segmentation algorithm for coronary OCT images based on neutrosophic theory, which achieves high-precision segmentation of fibrous plaques and lipid regions. In this paper, the method of transforming OCT images into T in the area of neutrosophics is redefined based on the membership function, and the segmentation accuracy of fiber plaques is improved. For the segmentation of lipid regions, the algorithm adds homomorphic filter enhancement images, and uses OCT to transform OCT images into I in the field of neutrosophics, and further uses morphological methods to achieve high-precision segmentation. In this paper, 40 OCT images from 9 patients with typical plaques were analyzed and compared with the results of manual segmentation by doctors. Experiments show that the proposed algorithm avoids the over-segmentation and under-segmentation problems of the traditional neutrosophic theory method, and accurately segment the patch area. Therefore, the work of this paper can effectively improve the accuracy of segmentation of plaque for doctors, and assist clinicians in the diagnosis and treatment of coronary heart disease.
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.
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.
Objective To assess efficacy of a mouthwash containing 0.1% cetylpiridinium on gingivitis and plaque and its safety. Methods Multi-center randomized double-blind trial with positive control and split-mouth comparison was designed. Scaling on teeth of left side were conducted at do then on those of right side at D8. The cases rinsed five times a day in same way with assigned agents. Efficacy was measured using before-after differences of clinical and microbial variables. Re-examinations were scheduled at D4 and D8. Brushing was refrained between D0 and D4, resumed between D4 and D8. Results There were 144 patients with gingivitis included, 4 lost follow up. Data of 69 cases in test group and 71 in control group could be analyzed. Baseline data analysis showed that distributions of sex, age and values of clinical and microbial variables in both groups were well comparable. At D4 plaque accumulations of the scaled side in both groups were in same level, and Gingival index (GI), sulcus bleeding index (SBI) and VAS for halitosis were significantly reduced. At D8 the measurements of plaque index (PI), GI, SBI and VAS of halitosis decreased significantly more than those of D4. More than half of the suspected pathogenic strains were eliminated and log value of its CFU/ml decreased significantly but at same level in both groups. The balance of intra-oral bacterial flora was not disturbed. Seventeen cases in test group (24.6%) had minor and transient adverse reactions related to the mouthwash. Antimicrobial tests in vitro confirmed that the test agent could kill or inhibit growth of the pathogenic bacteria involving with oropharyngeal infection, gingivitis, periodontal diseases and caries. Conclusion The mouthwash containing cetylpiridinium could inhibit plaque, reduce severity of gingivitis and halitosis, with acceptable minor adverse reactions, similar to those of the marketed cetylpiridinum solution.