PHASIC CORONARY FLOW MEASUREMENT BY DUAL-ENERGY DSA

最近的研究强调了传统冠状动脉造影的局限性， 动脉造影这些局限性包括较大的内部观察者， 观察者之间的差异性是由主观视觉分级引起的， 冠状动脉狭窄病变此外，病理结果显示， 冠状动脉狭窄的严重程度与 根据冠状动脉造影片和狭窄的实际严重程度估计 在死后的心脏中测量到的损伤。因此，更多的生理 正在研究评估冠状动脉狭窄的方法。一 已经建议的参数是冠状动脉血流储备（CFR）。 数字减影参数血流成像技术 血管造影术（DSA）已经被提议作为测量CFR的手段。之一 这些参数成像技术的局限性在于 它们仅能够测量相对冠状动脉流速。 因此，他们不能检测复杂的因素，如升高 基线冠状动脉血流量。此外，最近有报道称， 除了狭窄以外的因素，例如灌注压，也可能影响CFR。 此外，使用颞叶的最大临床问题之一 减影技术在人体心导管实验室， 参数成像流量测量被认为是运动 重合失调伪影。本研究计划的目的是 开发并在患者中应用相位容积冠状动脉血流 利用运动免疫双能量数字测量技术 减法模式更具体地说，目的是：（l）调查 影响绝对体积的物理和生理参数 血流测量(2)对假设的调查，即真实的- 时间双能量减影结合第一遍 分布分析可用于测量相位体积 冠状动脉血流量准确。测量将在 组织减影双能量（与时间减影相反）图像 并且将产生绝对（与相对相对）体积血流 测量（3）相位比假设的调查 充血的冠状动脉血流速度和其灌注压是一个 冠状动脉狭窄严重程度的可靠定量测量。（四） 对充血舒张期与舒张期比值的假设的研究 收缩期流速是评估狭窄的有用参数 严重性。(5)绝对冠状动脉血流量的实现 心导管插入术中人体研究的测量技术 实验室这项研究的结果将提供改进的 冠状动脉狭窄程度的生理学定量方法 在患者中，使用双能量数字减影血管造影术。的 运动免疫双能量系统可以实现与小 对心导管插入术中现有仪器的改进 实验室这种量化技术可以用来测量 每例患者的绝对相位冠状动脉血流和血流储备 接受放射学检查。

Recent studies have emphasized the limitations of conventional coronary angiography. These limitations include the - large intraobserver and interobserver variability that result from subjective visual grading of coronary stenotic lesions. Furthermore, pathologic findings have shown a lace of correlation between the severity of coronary stenosis as estimated from coronary angiograms and the actual severity of stenotic lesions measured in postmortem hearts. As a result, more physiological means of assessing coronary artery stenosis are being investigated. One parameter that has been suggested is the coronary flow reserve (CFR). Parametric flow imaging techniques utilizing digital subtraction angiography (DSA) have been proposed as a means of measuring CFR. One of the limitations of these parametric imaging techniques is the fact that they are capable of measuring only relative coronary flow rates. Therefore, they can not detect complicating factors such as elevated baseline coronary blood flow. Also, there have been recent reports that factors other than stenosis, such as perfusion pressure, may affect CFR. In addition, one of the greatest clinical problems of using temporal subtraction technique in the human cardiac catheterization laboratory for parametric imaging flow measurement has been reponed to be the motion misregistration artifacts. The purpose of this research plan is to develop and apply in patients a phasic volumetric coronary blood flow measurement technique utilizing a motion immune dual-energy digital subtraction mode. More specifically, the aims are: (l) investigation of the physical and physiological parameters affecting absolute volumetric blood flow measurement. (2) investigation of the hypothesis that real- time dual-energy subtraction in conjunction with the first pass distribution analysis can be utilized to measure phasic volumetric coronary blood flow accurately. The measurement will be performed on tissue subtracted dual-energy (as opposed to temporal subtraction) images and will produce absolute (as opposed to relative) volumetric blood flow measurement (3) Investigation of the hypothesis that the ratio of phasic hyperemic coronary blood flow rate and its perfusion pressure is a reliable quantitative measure of coronary stenosis severity. (4) Investigation of the hypothesis that the ratio of hyperemic diastolic to systolic flow rates is a useful parameter in assessing the stenosis severity. (5) Implementation of the absolute coronary blood flow measurement technique for human studies in the cardiac catheterization laboratory. The results of this research will provide improved physiological methods of quantitating coronary artery stenosis severity in patients, using dual-energy digital subtraction angiography. The motion immune dual-energy system can be implemented with minor modification of the existing instrumentation in a cardiac catheterization laboratory. This quantification technique could be used to measure absolute phasic coronary flow and flow reserve in every patient undergoing radiographic studies.