中文摘要：

目的通过冠状动脉体模实验,探讨斑块性质和血管管径对64排CT冠状动脉成像血管狭窄显示准确性影响。方法使用心脏动态体模建立不同类型冠状动脉体外模型,模拟血管管径分别为2.5、3.0、3.5、4.0 mm,管腔内对比剂浓度设置为（346±13.6）Hu。模拟斑块CT值为（14±9.6）Hu和（712±15.1）Hu,用以模拟软斑块和钙化斑块,模拟狭窄程度分别为25%、50%、75%。使用64排螺旋CT行回顾性心电门控扫描,选择75%R-R间期单扇区重建。使用AW4.2工作站进行多平面重组（Multiplanar Reformation,MPR）获得模拟冠状动脉最佳长轴位影像,在每段模拟血管狭窄影像上各选取10个位置测量管径和计算狭窄程度平均值。应用单样本t检验比较模拟血管影像管径和狭窄程度与模型数据之间差别,应用独立样本t检验进行两者间比较,用ANOVA进行多组数据的比较。结果经单样本t检验及方差分析显示,各组不同管径及狭窄的绝对测量值均与标准值存在统计学差异。软斑块组狭窄的相对测量值（狭窄率）与标准值的差异无统计学意义,相同狭窄程度、不同管径之间的差异均无统计学意义。测量所得钙化组狭窄率与标准值存在显著性差异,相同狭窄程度、不同管径之间均存在显著性差异。经独立样本t检验分析,软斑块与钙化组之间的绝对和相对测量值均有显著性差异,钙化组测量值高估了狭窄程度。结论 64排CT冠状动脉成像能够评价血管相对狭窄程度,但对钙化斑块的评价存在高估。

英文摘要：

Objective To evaluate the effect of vessel diameter and plaque nature on the accuracy of stenosis measurement in 64-row CT coronary angiography by conducting experiments with a cardiac phantom.Methods By adopting an adjustable pulsating cardiac phantom,different models of the simulated coronary arteries are established.Simulate vascular diameters of these models are 2.5 mm,3.0 mm,3.5 mm and 4.0 mm respectively.The concentration of contrast medium in vascular lumen of these models is（346±13.6） Hu.CT values of simulated plaques used to simulate soft plaques and calcified plaques are（14±9.6） Hu and（712±15.1） Hu and stenosis degrees of these plaques are 25%,50% and 75% respectively.Retrospective ECG gating is scanned by Lightspeed VCT,and Half reconstruction is performed at 75% R-R interval.All data are sent to AW4.2 workstation for multiplanar reformation（MPR） to obtain the best longitudinal section.Calibers and stenosis degrees of 10 random sections on stenosis images of simulation vessels are measured.One-sample t test is used to evaluate the accuracy of calibers and stenosis degrees.The two groups of different plaques are compared by using independent-samples t test.The data of multiple groups are compared by ANOVA（analysis of variance）.Results of one-sample t test and ANOVA shows that the absolute measure value of all groups with different calibers and stenosis degrees has statistics difference with the standard value.In the group of soft plaques,there is no statistics difference between the measured relative stenosis degrees with the standard value,nor between the measured relative degrees among different calibers.However,in the group of calcified plaques,statistical differences are found in these comparisons of independent-samples t test shows that there are statistical difference between the absolute and relative measured values between the groups of soft and calcified plaques.The stenosis degree was exaggerated in calcified plaques.Conclusion Relative stenosis degree of coronary arteri