Quantification of coronary calcium mass by dual energy fluoroscopy

描述（由申请人提供）：有效的预防策略需要早期发现亚临床动脉粥样硬化性心脏病。冠状动脉钙的影像学检测和定量在这方面进行了广泛的研究。冠状动脉钙与病理表现和冠状动脉事件之间有很强的联系。最近的研究利用计算机断层扫描来评估冠状动脉钙。由于干扰本底组织结构和无法客观地定量钙含量，透视评估受到低灵敏度的限制。双能成像没有这两个限制，为动脉粥样硬化的早期检测提供了低剂量、低成本的解决方案。提出的研究将开发一种运动不敏感的双能量减法技术，将提供冠状动脉钙的密度测量。更具体地说，目的是：(1)研究假设，冠状动脉的绝对钙质量可以通过虚幻和动物实验的密度测量技术精确测量。密度分析将在组织抑制双能量图像上进行，并将产生绝对（相对于相对）钙质量。(2)验证双能x线镜测得的人体志愿者钙质量与电子束计算机断层扫描测得的钙评分Spearman相关系数大于0.95的假设。(3)确定两种技术在区分流行冠心病患者和非流行冠心病患者方面是否存在差异。本研究将提供一种使用双能成像无创定量冠状动脉钙的方法。最有可能的是，在未来几年，基于图像增强电视系统的心脏成像将被平板探测器所取代。正如过去几年的快速发展所表明的那样，新的数字系统将允许开发更复杂的分析技术。基于密度测量的冠状动脉钙质定量是一种很有前途的分析技术，可以提供新的数字系统。迄今为止，时间减法对心脏运动的敏感性阻碍了心脏成像数字图像处理技术的发展。双能成像由于其运动不敏感，可作为心脏定量分析的基础。

DESCRIPTION (provided by applicant): Effective preventive strategies require early detection of sub-clinical atherosclerotic heart disease. Radiographic detection and quantification of coronary artery calcium has undergone extensive research in this regard. There is a strong association between coronary calcium and both pathologic findings and coronary events. Most recent research has utilized computed tomography for evaluating coronary calcium. Fluoroscopic evaluation is limited by low sensitivity, due to interfering background tissue structures and inability to objectively quantify calcium content. Dual energy imaging does not suffer from these two limitations and offers a lower dose and lower cost solution to early detection of atherosclerosis. The proposed research will develop a motion insensitive dual energy subtraction technique that will provide densitometry measurements of coronary calcium. More specifically, the aims are: (1) Investigation of the hypothesis that the absolute calcium mass in coronary arteries can be accurately measured using a densitometry technique with phantom and animal studies. The densitometry analysis will be performed on tissue suppressed dual energy images and will yield absolute (as opposed to relative) calcium mass. (2) To test the hypothesis that calcium mass measured in human volunteers with dual-energy fluoroscopy and calcium score measured with electron beam computed tomography have a Spearman correlation coefficient higher than 0.95. (3) To establish the presence or absence of a difference between the two technologies in discriminating persons with prevalent coronary heart disease from those without prevalent coronary heart disease. This research will provide a method to non-invasively quantify coronary artery calcium using dual energy imaging. Most likely, cardiac imaging with image intensifier television based systems will be replaced with flat-panel detectors in the coming years. As the rapid development in the last few years has shown, the new digital systems will allow development of more sophisticated analysis techniques. Densitometry based quantification of coronary artery calcium mass is one promising analytical technique that new digital systems may provide. To date, the sensitivity of temporal subtraction to cardiac motion has hampered the development of digital image processing techniques for cardiac imaging. Dual-energy imaging, because of its motion insensitivity, can serve as a foundation for quantitative cardiac analysis to proceed.