| Objective: To assess the clinical application value of cardiac magnetic resonance feature tracking(CMR-FT)in quantitatively estimating left ventricular(LV)myocardial strain in patients with acute ST-segment elevation myocardial infarction(STEMI)after percutaneous coronary intervention(PCI).Material and method: Seventy-eight patients with acute STEMI from October 2017 to December 2018 in shenzhen people's hospital were included.All patients underwent CMR imaging in 2 to 6 days after successful PCI and their complete clinical data were recorded.The LV global and segmental strain,LV cardiac function,the volume of LV infarction and microvascular obstruction(MVO)were obtained by post-processing with CVI42 software.Consistency analysis was performed between and within groups.Pearson correlation analysis was used to test the correlation between the LV myocardial strain and cardiac function or infarct volume.Segmental myocardial infarction in LV was divided into these groups: presence or absence myocardial infarction,with or without MVO and transmural or non-transmural myocardial infarction.The quantitative data between the two groups were compared by two independent sample t-test or Mann-Whitney U test.The diagnostic efficiency of transmural myocardial infarction and MVO was analyzed by ROC.Ten patients were followed up after 6 months.Results:(1)The ICC values of GPRS/PRS,GPCS/PCS and GPLS/PLS between observers were 0.926/0.829,0.934/0.915 and 0.522/0.651,within the group were 0.979/0.908,0.994/0.959 and 0.748/0.773,respectively,which showed a good consistency.GPRS,GPCS,GPLS were strongly correlated with LVEF(all P<0.001)and infarct volume(all P<0.001).(2)There was no significant difference in GPS and GTTP between transmural myocardial infarction and non-transmural myocardial infarction(P>0.05).PRS,PCS,PLS,TTPr,TTPc and TTPl were significantly different between non-infarct group and infarct group(TTPl P=0.002,other parameters P<0.001).There were statistical differences in PRS(P=0.002)and PCS(P<0.001)between transmural infarction group and non-transmural infarction group.When PRS was 24.45%,the sensitivity and specificity of identifying the transmural myocardial infarction were 70.3% and 77.8%.The sensitivity and specificity of-16.55% in PCS were 74.5% and 70.3%.(3)There was no significant difference in GPS and GTTP between the MVO group and non-MVO group.However,PRS,PCS and PLS were statistical differences in between the MVO group and non-MVO group(P<0.05).When PRS was 24.65%,the sensitivity and specificity of myocardial MVO detection were 89.0% and 60.6%.The sensitivity and specificity of-14.05% in PCS were 75.7% and 75.9%.(4)After 6 months follow-up in the ten patients,LVEF was improved.However,the recovery of LVEF in patient with MVO was worse than that in patient without MVO,and the absolute values of PRS,GPLS and PLS in MVO group were lower than those before 6 months.Furthermore,11 segments of transmural myocardial infarction transformed into non-transmural myocardial infarction,and the volume fraction of IS and MVO decreased.Conclusion:(1)CMR-FT is a reliable and convenient method for quantitative assessment of left ventricular strain after PCI in patients with acute STEMI.The strain measured have good correlation with the ejection fraction and the infarct volume fraction.(2)PRS and PCS have abilities to distinguish non-infarcted myocardium from infarcted myocardium,accurately identify the occurrence of the MVO and transmural myocardial infarction in patients with acute STEMI patients.It also provides a reliable new way for the indirect diagnosis of in patients with severe renal insufficiency(3)CMR-FT is a new tool with potential value in the follow-up and prognostic evaluation of STEMI patient after PCI. |
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