| Acute coronary syndrome (ACS) is the clinical syndrome based on the pathological basis of coronary atherosclerotic plaque rupture or erosion, secondary completed or incompleted occlusive thrombosis, including acute myocardial infarction (AMI),unstable angina pectoris (UAP) and the sudden cardiac death (SDC).More and more evidence indicate that the vast majority of acute coronary syndrome (ACS) is due to the incidence of plaque rupture (or intimal erosion) and the subsequent syndrome caused by thrombosis, The CT value of coronary artery plaque in patients with ACS is lower than in patients with non-ACS, and the CT value of ACS in patients with vascular lesions of the plaque is lower than in patients with non-vascular disease. So the nature of atherosclerotic plaque have an important relationship with acute coronary events:Calcified plaque is more stable and rarely falls off plaque, and the soft plaque and fibrous plaque is unstable and easy to break down.This fragile plaque has high cholesterol, big lipid core, thin fibrous cap which coveries the plaque. The characteristics of inflammatory cell infiltrating to injury fibrous cap is easy to develop into a complete obstruction of blood vessels to induce myocardial infarction.Different morphoous and composition of coronary artery plaque decide the stability of the plaque, so we need the higher-resolution imaging technology to determine the fine structure of coronary plaque ,so that we can discover the vulnerable non-stable plaque before catastrophic breakdown. IVUS (intravascular ultrasound, IVUS) was considered the the gold standard of plaque detection, but its high inspection cost and traumatic occlusion limits their clinical application, and because of the difficulty in quantitative analysis of plaque composition, IVUS Evaluation of the organizations characteristics of plaque also has some limitations.For a long time selective coronary angiography (coronary angiography, CAG) remains the "gold standard"to diagnose coronary artery disease.But it is invasive examination, which is very expensive and difficult to be accepted by the patients. So Multi-slice spiral CT (multislice compued tomography, MSCT) appears and greatly promots the development of non-invasive coronary artery imaging.Objective:Higher spatial resolution, density resolution of 64-slice CT, can display the atherosclerotic plaque of trunk and main branches of coronary artery can observe plaque morphology, density and the corresponding parts of the lumen from different directions, so that we can determine the nature of the plaque and the extent of stenosis of the corresponding site of luminal, and reliably identify plaque with lipid-rich or fiber-rich, and help to evalue plaque stability.64-slice spiral CT can measure CT value of plaque and divide the atherosclerotic plaque into soft plaque, calcified plaque and mixed plaque.Plaque classification has important clinical significance. This study comparies with selective coronary angiography to explore the 64-slice spiral CT: 1, by measuring the CT value of plaque to determine the nature of plaque and plaque stability of the value and effect; 2, to discuss the relationship of different nature of plaque leading to the degree of luminal stenosis; 3, to explore the relationship between different types of plaque stability and risk of coronary heart disease.Methods: from March 2008 to December 2008 in our hospital 102 cases of patients, 63 cases of male, 41 cases of female. Patients were divided into myocardial infarction groups (myocardial infarctiong, MI) and chronic stable angina group (stable angina pectoris, SA).MI Group contains 48 cases, 32 cases of male, 16 cases of female, aged 40-79 years old, on average (62.6士8.5) years old, 23 cases of hypertension, hyperlipidemia in 15 cases; SA group contains 54 cases, 31 cases of male, 23 cases of female , age 48-74 years old, on average (59.9士7.4) years old, 18 cases of hypertension, hyperlipidemia in 14 cases, two sets of baseline clinical data was no significant difference.Coronary angiography and 64-slice CT coronary angiography ecalue the extent of the main coronary artery stenosis and the nature of the plaque in this coronary artery. The unit of CT value is the HU (Hounsfield Units). According to CT value soft plaque plaque is divided into 6 HU士28HU, mixed plaque 83HU士17HU and calcified plaque 489HU士372HU. Statistical methods use SPSS13.0 package to conduct statistical analysis.Results: 1,In 1326 (102x13) Section of coronary artery segments of 102 cases, the coronary artery image is good ,can meet the imaging evaluation of the 912 vascular paragraphs (912/1326, 68.8%).2,CAG count found 198 lesions, MSCT identified lesion 181, which showed no statistical significance (P = 0.107> 0.05). Compared with CAG, sensitivity of 64MSCT is 83.8%, specificity is 89.8%, positive predictive value is 97.2%, negative predictive value is 98.3%.3,A total of two groups of patients with coronary plaque detected 291, the number of plaques between the two groups was no significant difference (P> 0.05); The distribution in coronary artery of MI group plaque and the SA group plaque was not significant ( P> 0.05); MI group-considered soft plaque, calcified plaque follows by; SA group considered calcified plaque and mixed plaque ,the difference between them was statistically significant (P <0.01). 4.Soft plaque mainly distributed in the mild stenosis lesions. Severe stenosis mainly considered mixed plaques. plaques of different types between the degree of stenosis was statistically significant, P <0.05.Conclusion: 64 MSCT coronary angiography due to high spatial resolution, has a high diagnostic accuracy to coronary artery disease and the nature of plaque,can possess non-invasive evaluation to the form and nature of coronary atherosclerotic plaque and stability of plaques, can be used as a reliable means of diagnosis of coronary heart disease for clinical .More importantly, it can predict the risk of coronary heart disease.1. 64-slice CT coronary angiography for the detection of coronary artery stenosis with high accuracy, with the CAG in this study contrast, CAG showed that the number of lesions Support 198, MSCT shows the number of lesions Support 181, 64MSCT sensitivity of 83.3 % specificity, 89.8%, 97.2% negative predictive value, positive predictive value of 98.3%. 64-slice CT coronary angiography for detection of coronary artery plaques with high display rates ,two groups of patients with coronary artery were detected in 291 patches, MI-based soft plaque group, a total of 58, followed by calcified plaque, for a total of 52, SA-based groups to calcified plaque, for a total of 65, followed by mixed plaque, for a total of 55。291 plaques of coronary artery distribution in the study, MI Group LAD plaque detected up to a total of 59, RCA times, for a total of 46; SA Group LAD plaque detected up to a total of 54, RCA Group times, for a total of 42. Vascular lesions of this study show that the degree of luminal stenosis and plaque type has obvious relevance, MI group <50% of lesions, soft plaque in the main, for a total of 29, in> 70% lesion to a mixed plaque and mainly of calcified plaque, respectively, 20,24 months. This shows that the soft plaque are mainly distributed in the lesions of mild stenosis, severe stenosis and calcified plaque mixed mainly plaque. 64-slice spiral CT coronary artery imaging with high spatial and density resolution, the application of a variety of reconstruction techniques, be able to clear now that the three vessels and patch density, size, shape and location, eliminating the post-processing image Z axis direction of the edge of the ladder-like images, so that better quality of three-dimensional imaging for clinical diagnosis and treatment to provide more information. |
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