冠脉狭窄的功能变化对临床血运重建和预后较单纯狭窄程度的判断更重要。基于256排CT原型机对冠脉强化梯度、心肌血流灌注梯度的定性研究初步表明这些指标与冠脉狭窄后血流动力学改变有关。.基于时相均匀性16cm宽探测器CT平台，建立冠脉不同狭窄程度和心肌灌注状态的动物模型，进行负荷/静息CT心肌灌注和冠脉成像，根据时间密度曲线的指标定量分析评估冠脉内血流梯度、跨壁心肌强化程度比值，分别与经导管测量的FFR和CFR进行相关性和回归分析，同时分析冠脉内血流梯度和心肌灌注梯度、心肌灌注梯度与MR首过心肌灌注及心脏标本的荧光微球分析法测量心肌血流量的关系，以探讨无创性CT心肌灌注成像一站式检查在评价冠脉和心脏形态学变化的基础上，定量评估冠脉狭窄后血流动力学变化的可靠性及其病理学基础。以此为基础指导部分患者的CT检查，以期实现冠心病冠脉形态学和功能学综合评价的最优化的一站式检查，更好地指导临床治疗与预后。

It is well known that functional assessment of coronary stenosis is much more significant than determination of lesion morphology only. The initial qualitative study based on 256-slice CT（prototype of 320-detector CT）has shown that the coronary opacification gradient may be related to the hemodynamic change of coronary stenosis, but it's hemodynamic fundamental and clinical value needs further study..Newest 640 slice CT, which has 16cm width detector and unique cardiac temporal uniformity, allows more accurate assessment of coronary blood flow and myocardial perfusion . With canine model with different extent stenosis of LAD, a new method . based on the time-density curve to assess coronary blood flow gradient (defined as dynamic CT based coronary enhancement ratio, dCER) and myocardial perfusion gradient(defined as dynamic CT based transmural perfusion gradient, dTPR) will be studied. The correlation of dCER with fractional flow reserve(FFR) measured by pressure-wire will be analyzed, as well as dTPR and TPR derived from stress MRI perfusion Imaging. And regression analysis between dCER and FFR will be done. A multiple regression analysis will be performed to study the relationship among parameter of coronary blood flow(dCER、CFR) and myocardial perfusion calculated by CT. The accuracy of CT myocardial perfusion imaging will be confirmed by fluorescent particle technique in vitro, as well as MRI perfusion imaging. The object of this study is to reveal the hemodynamic significance and fundamental of function parameter derived from 640 slice CT volume scanning mode, and ability to predict functional stenosis by the mode, then it's hoped that an optimal noninvasive one-stop-shop method can be established to assess functional relevant stnosis and provide more comprehensive information for therapy strategy and prognosis.