Animal Experimental Study For Eveluating The Efficacy Of Dual-energy Coronary CTA In The Diagnosis Of Acute Myocardial Infarction

Objective: To analyze and explore the ability of DE-CCTA iodine value to quantitatively evaluate AMI,and to evaluate the diagnostic efficiency of DE-CCTA.Methods: The AMI model was made by ligating the distal anterior descending coronary artery of domestic pigs under open thoracotomy.One day after successful modeling,DE-CCTA,LGE and T1 mapping scanning were performed before and after injection of contrast medium.Histopathological sections were made as the gold standard and LGE as horizontal control.The sensitivity,specificity,diagnostic coincidence rate,positive predictive value,positive likelihood ratio,negative predictive value and negative likelihood ratio of various evaluation methods of DE-CCTA and T1 mapping subjective diagnosis of AMI before and after injection of contrast medium were calculated.The myocardial iodine concentration,NID value and myocardial T1 value before and after injection of contrast medium were analyzed by ROC curve,and the diagnostic efficiency was evaluated and the diagnostic threshold was determined.Results:(1)among the various evaluation methods of DE-CCTA,the specificity of l30 keV virtual single energy diagnosis of AMI is the highest(92.53%),but the sensitivity is lower(73.33%),the sensitivity of iodine map is the highest(100%),but the specificity is low(68.66%),and the sensitivity and specificity of the best CNR virtual single energy are higher(86.67%,91.04%),The diagnostic coincidence rate(90.24),Yoden index(0.78)and Kappa value(0.70)were the highest.DE-CCTA joint evaluation: the specificity(98.50%)and diagnostic coincidence rate(91.46%)of joint evaluation 2 were the highest,and the sensitivity of joint evaluation 3 was the highest(100%),which significantly increased the specificity of iodine map(68.66% hand 80.6%).(2)there were significant differences in iodine concentration,NID value and myocardial T1 value before and after contrastmedium injection between normal and infarcted myocardium(P <0.05).(3)ROC curve analysis results: when the myocardial iodine concentration is 1.750 mg/ ml,the area under the curve is 0.979,the sensitivity and specificity are 100,95.5% and the optimal threshold is 0.065 mg/ ml,the area under the curve is 0.997,the sensitivity and specificity are 100% and 98.5%.Before injection of contrast medium,the area under the curve when the optimal threshold of myocardial T1 was 1112.05 ms was 0.962,and the sensitivity and specificity were 86.7% and 100%.After injection of contrast medium,the area under the curve was 0.938 when the optimal threshold of myocardial T1 was 590.37 ms,and the sensitivity and specificity were 100% and 88.1%.Conclusion: CMR-LGE subjective evaluation of AMI diagnostic efficacy is higher than DE-CCTA;the combination of DE-CCTA evaluation methods can improve the diagnostic efficiency of AMI;quantitative evaluation of AMI: myocardial iodine concentration,NID value diagnostic efficiency is better than T1 value,DE-CCTA has great potential in the diagnosis of AMI.