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目的:探讨动态CT心肌灌注成像（CT-MPI）对冠状动脉慢性完全性闭塞（CTO）患者心肌灌注功能及冠状动脉侧支循环（CCC）的意义。方法:自2019年4月至12月前瞻性收集郑州大学华中阜外医院冠状动脉造影证实为CTO的患者进行动态CT-MPI扫描，获得每个心肌节段的灌注参数，包括心肌血流量（MBF）、心肌血流量比值（rMBF）、心肌血容量（MBV）、开始时间（TTS）、达峰时间（TTP）、血管外细胞外容积（EEV）、流量提取乘积（FE）及灌注毛细血管血容量（PCBV）。以SPECT为参考标准，比较大致正常和异常、不同缺血程度、存活与梗死心肌节段参数间差异，采用ROC曲线下面积（AUC）比较其诊断效能。以冠状动脉造影Rentrop分级为标准，比较CCC良好组和不良组心肌节段参数间差异及其与Rentrop分级间的相关性。结果:最终纳入21例患者。灌注异常组的MBF、rMBF、MBV、FE、PCBV及EEV均低于灌注大致正常组，而TTS及TTP高于大致正常组（n P<0.05）。其中MBF的AUC最大，为0.809，最佳截断值为71.75 ml·100 ml?1·min?1，灵敏度和特异度分别为0.71和0.80。MBF及rMBF随着心肌缺血程度加重而降低，但中、重度组间差异无统计学意义（n P值分别为0.811和0.696）。当鉴别梗死及存活心肌时，rMBF的AUC最大为0.896，最佳截断值为69.17%，灵敏度和特异度分别为0.75和0.92。CCC良好组MBF、MBV、FE及EEV明显高于不良组（n P均<0.05），但与Rentrop分级间无明显相关性（|n r|均<0.3）。n 结论:动态CT-MPI定量参数对CTO患者心肌灌注功能及CCC状态具有良好的诊断价值，但与CCC Rentrop分级之间相关性较差，其意义有待进一步研究。“,”Objective:To investigate the significance of using dynamic CT myocardial perfusion imaging (CT-MPI) for evaluation on myocardial perfusion function and coronary collaterals circulation (CCC) in patients with coronary chronic total occlusions (CTO).Methods:CTO patients who were diagnosed by coronary angiography (CAG) were prospectively enrolled in this study from April 2019 to December 2019. All patients were scanned with dynamic CT-MPI protocol using third generation dual-source CT. The parameters of CT-MPI, including myocardial blood flow (MBF), ratio of myocardial blood flow (rMBF), myocardial blood volume (MBV), time to start (TTS), time to peak (TTP), extravascular extracellular volume (EEV), flow extraction product (FE) and perfusion capillary blood volume (PCBV) were calculated and recorded. SPECT was used as the reference standard. The differences of parameters between normal and abnormal, different degrees of ischemia, survival and infarction in cardiac perfusion segments were compared. The diagnostic efficacy was analyzed using the area under the ROC curve (AUC). CT-MPI parameters were compared between well-and poorly-developed collaterals groups based on Rentrop grade of CAG. Spearman analysis were performed to analyze the association between the CT-MPI parameters and CCC Rentrop grade.Results:Twenty-one patients were enrolled in the study. MBF, rMBF, MBV, FE, PCBV and EEV in abnormal perfusion group were lower than those of normal perfusion group (all n P<0.05). TTS and TTP were higher in abnormal perfusion group than those of normal perfusion group (alln P<0.05). The AUC of MBF was 0.809, which was highest among all the parameters. With a cutoff value of 71.75 ml·100 ml?1·min?1, the sensitivity and specificity of MBF were 0.71 and 0.80 respectively. MBF and rMBF were decreased as ischemic level increasing, with no significant deference found between moderate and severer ischemic groups (n P=0.811 andn P= 0.696). The AUC of rMBF was 0.896 in distinguishing myocardial survival from infarction, which showed the best performace. With a cutoff value was 69.17%, the sensitivity and specificity of rMBF were 0.75 and 0.92, respectively. CT-MPI parameters of well-developed collaterals group were significantly higher than those of poorly-developed collaterals group (all n P<0.05). However, there were poor associations between CT-MPI parameters and Rentrop grade (all |n r|<0.3).n Conclusions:Quantitative parameters of CT-MPI show good diagnostic performance in evaluating myocardial perfusion function and CCC of CTO patients, but it seems no significant correlation between quantitative parameters of CT-MPI and Rentrop grade.