Abstract： Objective:To investigate the diagnostic value of myocardial blood flow quantitative imaging with cadmium zinc telluride (CZT) SPECT in patients with high-risk coronary artery disease (CAD).Methods:A total of 148 patients (82 males, 66 females, age: (63.8±8.2) years) who successfully completed CZT SPECT dynamic acquisition and routine SPECT myocardial perfusion imaging (MPI) in TEDA International Cardiovascular Hospital from November 2018 to October 2020 were analyzed retrospectively. According to the results of coronary angiography (CAG), patients were divided into two groups: high-risk CAD group and low-to-medium-risk CAD group. At the case level, quantitative parameters (stress myocardial blood flow (sMBF), rest myocardial blood flow (rMBF) and myocardial flow reserve (MFR)), semi-quantitative parameters (summed stress score (SSS), summed rest score (SRS), summed difference score (SDS) and transient ischemic dilation (TID)) and left ventricular function parameters of two groups were compared. Diagnostic accuracy was evaluated by ROC curve analysis. At the vascular level, the correlation between the degree of coronary artery stenosis and some parameters was analyzed. Mann-Whitney U test, logistic regression, Spearman rank correlation analysis and DeLong test were used for statistical analysis. Results:Case level analysis showed that MFR and sMBF in high-risk CAD group were significantly lower than those in low-to-medium-risk CAD group (1.36(0.87, 1.64) vs 2.74(2.30, 3.33), 1.06(0.69, 1.48) vs 2.50(1.73, 2.95) ml·g -1·min -1; U values: 628.0 and 853.5, both P<0.001). MFR and SDS were independent predictors of high-risk CAD patients (odds ratio ( OR)=0.251(95% CI: 0.136-0.464), P<0.001; OR=1.188(95% CI: 1.026-1.375), P=0.021), and MFR was more capable of predicting high-risk CAD. MFR and sMBF had the highest accuracy in diagnosing high-risk CAD (AUCs: 0.885 and 0.844). Differences of AUCs between MFR and other parameters were statistically significant ( z values: 1.99-6.77, all P<0.05), and the best diagnostic cut-off value was ≤1.83 (sensitivity: 85.90%; specificity: 85.71%). Vascular level analysis showed that MFR and sMBF( R2 values: 0.39 and 0.35, both P<0.001) were negatively correlated with the degree of coronary stenosis, while SSS, SRS and SDS ( R2 values: 0.22, 0.12 and 0.14, all P<0.001) were positively correlated with the degree of coronary stenosis. Conclusion:Compared with conventional SPECT MPI, CZT SPECT myocardial blood flow quantitative imaging has better diagnostic efficacy and clinical value in patients with high-risk CAD.