The Experimental Research On Detection Of Atherosclerotic Plaque Using Dynamic Contrast Enhanced MR Lamging

The atherosclerosis already becomes one of the disease endangering healthy of human being ,the atherosclerotic plaque breaking is one of the main cause of disease to arouse heart and cerebrovascular accident,according to the life statistical data that Department of Health announces, our country the number of people of heart and cerebrovascular accident disease death account general death toll one-third. To diagnose arteriosclerosis mostly according to the laboratory examination such as blood the grease, C-reactive protein and clinically symptom,sometimes to be able to make the diagnose clear just now during the period of occurrence organ damage The atherosclerosis is on one's own dangerous factor of heart and cerebrovascular accident atherosclerotic plaque breaking , bleeding and thrombus abscission will be arousing unexpected heart and cerebrovascular accident disease therefore, early detcting and estimating that vulnerability arteriosclerosis plaque to precaut heart and cerebrovascular accident has important significance.With the improvement of magnetic resonance scanning technology,magnetic resonance as a noninvasive, high spatial resolution temporal resolution imaging examination has become one of the important means to detect atherosclerotic plaque This study is divided into three sections explore the dynamic contrast-enhanced magnetic resonance scanning clinical value in atherosclerotic plaque. The first part is the establishment of early (high-fat feeding 10-12 weeks) and late (20-24 weeks high fat feeding) groups rabbit abdominal aorta atherosclerotic model, compare multiple sequence magnetic resonance Plain scanning and dynamic contrast-enhanced magnetic resonance scanning technology in the early detection of rabbit abdominal aorta atherosclerotic plaque accuracy. Comparing imaging findings and pathological results of HE staining, immunohistochemical staining results of CD31. High-fat feeding 10-12 weeks found that the performance of DCE-MRI scans 46 Atherosclerotic plaque-like enhanced lesions, including 38 pathological HE staining showing that small plaque formation, the accuracy was 83%, high-fat feeding 20-24 weeks group were found 60 arteriosclerosis plaque-like lesions, in which 51 HE staining visible plaque pathology, accuracy rate of 85% Dynamic contrast-enhanced magnetic resonance scanning accuracy was significantly higher than MR multiple sequence plain scan. The second part through the establishment of rabbit abdominal aorta atherosclerotic model (high-fat feeding 20-24 weeks) determination of atherosclerotic plaque dynamic contrast-enhanced magnetic resonance scan time-signal intensity parameter: the first-phase slope of the curve parameter S, the largest patch enhancement ratio Smax and plaque peak signal intensity enhanced rate of decline after the 120s Soutflow.The use of immunohistochemistry markers of atherosclerotic plaque within the new microvascular endothelial cells (CD31) macrophages (CD68).Application of statistical methods Analysis of dynamic contrast-enhanced magnetic resonance scan time-signal intensity curve parameters S, Smax, Soutflow with the new microvascular endothelial cell count, macrophage count in atherosclerotic plaque correlation results showed that: dynamic contrast-enhanced magnetic resonance scan time-signal intensity curve parameter S, Smax, Soutflow with the new microvascular cell count macrophage count in atherosclerotic plaque positively correlated. New research shows that: Atherosclerotic plaque vulnerability is closely related to plaque inflammation and the new microvascular in plaque, the new microvascular and the inflammatory cells in plaque increased is the vulnerability of atherosclerotic plaque characteristics at the molecular level. The existence of a large number of inflammatory cells around neovascularization. The new microvascular can promote inflammatory in plaque, plaque inflammation is closely related to increase the risk of plaque rupture occurs. New microvascular and inflammatory reaction in plaques plays a key role in atherosclerotic plaque formation and development process. The new microvascular and inflammatory in atherosclerotic plaque can be used as sign of the plaque vulnerability.The new microvascular endothelial cells and macrophages are at higher levels in the S, S_max, S_outflow larger atherosclerotic plaque plaque at the active stage and the plaque shows the vulnerability of atherosclerotic plaque characteristics. The third part of the establishment of high fat diet+simvastatin treatment group and simple high-fat feeding group rabbit abdominal aorta artherosclerosis model we detected two groups of atherosclerotic plaque dynamic contrast-enhanced magnetic resonance scan time-signal intensity curve parameters: the first-phase slope of the curve parameter S, maximum enhancement ratio S_max, peak signal intensity of enhanced rate of decline after the 120s signal strength S_outflow. Statins have pleiotropic including improvement of endothelial function, stabilize vulnerable plaque anti-inflammatory, antioxidant immune regulation, blood pressure inhibit thrombosis and so on. Simvastatin can inhibit the inflammatory reaction within plaques and the new microvascular formation, so as to achieve a stable plaque effect. High fat diet+simvastatin treatment group after 4 weeks of drug treatment significantly reduced blood fat while immunohistochemistry showed new microvascular endothelial cells and macrophages in atherosclerotic plaques, compared to those with high fat diet group was significantly reduced, indicating that simvastatin inhibited inflammatory reaction within plaques and the new microvascular formation in plaque, using a statistical method of analysis of two groups of dynamic contrast-enhanced magnetic resonance scan time-signal intensity curve parameters with significant differences in high fat diet+simvastatin treatment group ,magnetic resonance dynamic contrast-enhanced scan time-signal intensity curve parameters S, Smax, Soutflow significantly lower than simple high-fat fed group. The reason for the use of simvastatin treatment in inhibiting plaque inflammation and the new microvascular formation in plaque, the enhanced degree of atherosclerotic plaque is relevant to new microvascular in plaque vascular permeability and excretion kinetics of extravascular extracellular volume and a variety of composition in plaque Atherosclerotic plaques in the process of inflammation can cause an increase extracellular volume and cell endothelial permeability contrast agent can quickly access plaques extracellular space of atherosclerotic plaques, plaque shows enhancement.Dynamic contrast-enhanced magnetic resonance scan parameters the first-phase slope S and maximum enhancement ratio Smax describe contrast agent into the extravascular extracellular space of plaque, plaque peak signal intensity enhanced rate of decline after the 120s S_outflow describe agent leak out extravascular extracellular space of plaque. With the number of new microvascular in atherosclerotic plaque and the level of inflammatory response reducing, the contrast agent is not easy to spread to the extracellular space, magnetic resonance dynamic contrast-enhanced scan parameters S, S_outflow, S_max reduce indicating that the dose of contrast agent into atherosclerotic plaque decreases, the inflow and outflow to slow down. Dynamic contrast-enhanced magnetic resonance scan (DCE-MRI) parameters S, S_outflow, S_max can be used as a kind of evaluation of drug treatment of atherosclerotic plaque efficacy of quantitative indicators, S, S_outflow, S_max reduced drug treatment is effective and atherosclerotic plaque stabilization and plaque rupture occurs the possibility of shedding decreases.The experimental results show that: dynamic contrast-enhanced magnetic resonance scan (DCE-MRI) can not only early detection of atherosclerotic plaques accurately describe the atherosclerotic plaque morphology change, but also through the relation of dynamic contrast-enhanced magnetic resonance scan parameters S S_outflow, S_max and new microvessels and macrophage in atherosclerotic plaque evaluate the atherosclerotic plaque vulnerability. By comparing dynamic contrast-enhanced magnetic resonance scan parameters S, S_outflow, S_max changes before and after drug treatment in the clinical provide a reliable basis for evaluating drug efficacy of treatment of atherosclerotic plaque. In short, dynamic contrast enhanced MRI scan can provide clinical evaluation of atherosclerotic plaque vulnerability drug intervention in the treatment of atherosclerotic plaque provide a reliable and efficacy imaging basis,effective preventing heart and cerebrovascular accident.