Objective:To explore the feasibility of using Double FLASH coronary CTA (CCTA) to evaluate myocardial blood perfusion based on the original Patlak Plots.Methods:A total of 50 subjects with non-ischemic heart disease were prospectively included in the study who received dynamic myocardial CT perfusion (CTP) and Double FLASH CTA scans in General Hospital of Tianjin Medical University from January 2018 to January 2020 due to coronary heart disease or suspected coronary heart disease. The age of the enrolled patients was at least 18 years old and there was no moderate or above stenosis on CTA. The dynamic CTP images were analyzed by using CTP analysis software on FRONTIER platform to calculate the CTP derived MBF (MBF CTP). While the CTA derived MBF (MBF CTA) was calculated from the CT attenuation values of both aorta and myocardium segments on two scanning time set of Double FLASH CTA which were measured by two independent radiologists. Pearson correlation and Bland-Altman analysis were used to compare the results of MBF CTP and MBF CTA. Results:There was a strong linear correlation between MBF CTP and MBF CTA measurements. In the mid anteroseptal level: MBF CTA=0.936MBF CTP-11.999, r2=0.600, P<0.01. In the mid anterolateral level: MBF CTA=1.010MBF CTP-9.206, r2=0.448, P<0.01. In the apex: MBF CTA=0.822MBF CTP+16.904, r2=0.375, P<0.01. Bland-Altman analysis also showed there were no significant differences between MBF CTP and MBF CTA measurements. Compared with dynamic CTP scan, Double FLASH CTA mode significantly reduced the radiation dose [(4.33±1.89) mSv vs. (1.38±0.19) mSv, t=4.378, P=0.030]. Conclusions:This study validated the feasibility and accuracy of the MBF CTA measurement based on the theory of Patlak Plots only using Double FLASH CTA images. This method might have the potential to expand the clinical application of one-stop CTP examination for simultaneously evaluating coronary artery and myocardial ischemia in the clinic.