Value Of T2 Mapping In Cardiac Magnetic Resonance Imaging In Diagnosing Acute Myocardial Infarction:A Swine Study

Objective:To investigate the value of Cardiac Magnetic Resonance(CMR)T2 mapping in the diagnosis of acute myocardial infarction.Materials and Methods:Twenty-five mini-pigs with coronary artery occlusion were included in this study.The CMR examinations were performed at lweek,2weeks,3weeks,4weeks,2months,3months,and 4months after acute myocardial infarction(AMI).The CMR sequences included CMR cine,T2 mapping,and late gadolinium enhancement.After each CMR scanning,pigs were sacrificed and the hearts were excised,then triphenyltetrazolium chloride(TTC)staining,HE and Masson staining were performed.Regional T2 values of myocardial infarct,edema,and remote normal myocardium were measured on T2 maps generated by T2 mapping.Using TTC staining as the gold standard.Receiver operating characteristic(ROC)analysis was used to analyze the diagnostic accuracy of the T2 mapping for acute myocardial infarction and myocardial edema.Results:The mean T2 value in the myocardial infarction regions of acute myocardial pigs(70 ± 9ms)was significantly higher than that of the remote regions of acute myocardial pigs(46 ± 4ms)(P<0.0001).The T2 value in the myocardial edema regions of acute myocardial pigs(56 ± 8ms)was significantly higher than the remote regions(46 ± 4ms)(P<0.0001).The mean T2 value in the myocardial infarction regions of acute myocardial pigs(70 ± 9ms)was significantly higher than that of myocardial edema regions(56± 8ms).A T2 value of 57 milliseconds had the highest Youden index(0.75)with sensitivity of 92.5%and specificity of 82.2%to detect myocardial infarction,the area under the curve(AUC)was 0.92(95CI:0.895-0.955).For LGE,the AUC was 0.95(95CI:0.924-0.974)with sensitivity of 95.7%and specificity of 94.8%.T2 value of 50 milliseconds had the highest Youden index(0.70)with sensitivity of 86.2%and specificity of 84.0%to detect myocardial edema,the AUC was 0.92(95CI:0.889-0.951).This study considered that the T2 value in the range of 50ms-57ms can be diagnosed as myocardial edema.Conclusions:T2 mapping is technically feasible and accurate,and can detect myocardial infarction and myocardial edema.