Application Study On Evaluation Of Acute Myocardial Infarction Based On T1mapping

Objectives:To investigate the diagnostic value and reference range of longitud inal relaxation time quantitative(T1mapping)technique in patients with acute myoc ardial infarction(AMI)were and evaluated.Methods: Five pigs were selected as AMI model,and the distal left anterior descending branch was ligated to make A MI model.One day after modeling,1.5TCMR scanning was performed,and the sc anning sequence included delayed enhancement and T1 mapping,including the short axial position of left ventricle.At the end of CMR,the model was killed immedi ately,and the short axial 8mm sections of the left ventricle were taken and stained with HE.Compared with pathological images,the efficacy of LGE and T1 mappin g in subjective diagnosis of AMI was analyzed,and the statistical method of paire d t test was used to analyze whether there were significant differences in T1 value and ECV between normal myocardium and infarction myocardium before and after contrast medium injection.The threshold and efficiency of AMI diagnosis were de termined.Results:(1)according to the pathological results,the sensitivity,specificity and Jordan index of LGE and T1 mapping before and after contrast medium inject ion were as follows:LGE:93.33%,94.03%,0.873;.preT1mapping73.33%,88.06%,0.613;p ost T1mapping86.66%,97.01%,0.837;(2)according to the pathological results as the gold standard.There was significant difference in T1 value between normal myoc ardium and infarction myocardium before and after contrast medium injection,and there was significant difference in ECV value between normal myocardium and inf arction myocardium((P<0.05).(3)ROC curve analysis: the area under the curve,the diagnostic boundary value and 95% confidence interval of T1 value before cont rast medium injection were 0.916,1065.9ms and 95% CI 0.811 1,respectively.Aft er injection of contrast medium,0.956,604.35 ms,95% CI 0.891-1,ECV were 0.923,0.41,95% CI 0.824-1.Conclusion: Subjective evaluation and objective value m easurement of longitudinal relaxation time quantitative technique can be used to ev aluate acute myocardial infarction.T1 mapping and ECV values before and after co ntrast injection can be used in the differential diagnosis of infarction and non-infar ction myocardium.