Prognostic significance of T2 mapping in evaluating myocardium alterations in patients with ST segment elevation myocardial infarction / 中华危重病急救医学

OBJECTIVE@#To investigate the value of T2 mapping in the assessment of myocardial changes and prognosis in patients with acute ST segment elevation myocardial infarction (STEMI).@*METHODS@#A retrospective study was conducted. A total of 30 patients with acute STEMI admitted to Tianjin First Central Hospital from January 2021 to March 2022 were enrolled as the experimental group. At the same time, 30 age- and sex-matched healthy volunteers and outpatients with non-specific chest pain with no abnormalities in cardiac magnetic resonance (CMR) examination were selected as the control group. CMR was performed within 2 weeks after the diagnosis of STEMI, as the initial reference. A plain CMR review was performed 6 months later (chronic myocardial infarction, CMI). Plain scanning includes film sequence (CINE), T2 weighted short tau inversion recovery (T2-STIR), native-T1 mapping, and T2 mapping. Enhanced scanning includes first-pass perfusion, late gadolinium enhancement (LGE), and post-contrast T1 mapping. Quantitative myocardial parameters were compared between the two groups, before and after STEMI myocardial infarction. The receiver operator characteristic curve (ROC curve) was used to evaluate the diagnostic efficacy of native-T1 before myocardial contrast enhancement and T2 values in differentiating STEMI and CMI after 6 months.@*RESULTS@#There were no statistically significant differences in age, gender, heart rate and body mass index (BMI) between the two groups, which were comparable. The native-T1 value, T2 value and extracellular volume (ECV) were significantly higher than those in the control group [native-T1 value (ms): 1 434.5±165.3 vs. 1 237.0±102.5, T2 value (ms): 48.3±15.6 vs. 21.8±13.1, ECV: (39.6±13.8)% vs. (22.8±5.0)%, all P < 0.05]. In the experimental group, 12 patients were re-examined by plain CMR scan 6 months later. After 6 months, the high signal intensity on T2-STIR was still visible, but the range was smaller than that in the acute phase, and the native-T1 and T2 values were significantly lower than those in the acute phase [native-T1 value (ms): 1 271.0±26.9 vs. 1 434.5±165.3, T2 value (ms): 34.2±11.2 vs. 48.3±15.6, both P < 0.05]. ROC curve analysis showed that the area under the ROC curve (AUC) of native-T1 and T2 values in differentiating acute STEMI from CMI was 0.71 and 0.80, respectively. When native-T1 cut-off value was 1 316.0 ms, the specificity was 100% and the sensitivity was 53.3%; when T2 cut-off value was 46.7 ms, the specificity was 100% and the sensitivity was 73.8%.@*CONCLUSIONS@#The T2 mapping is a non-invasive method for the diagnosis of myocardial changes in patients with acute STEMI myocardial infarction, and can be used to to evaluate the clinical prognosis of patients.

The diagnostic value of quantitative imaging for acute myocardial infarction / 中华危重病急救医学

Objective:To explore the diagnostic performance of cardiac magnetic resonance imaging (CMR) with T1 mapping and T2 mapping for detection of acute phase of ischemic cardiomyopathy.Methods:Twenty-four patients with acute myocardial infarction (AMI) detected by coronary angiography from May 2020 to April 2021 in Tianjin First Center Hospital were selected. All patients underwent CMR (Philips Ingenia 3.0-T) at (9±4) days after definite diagnosis, which was defined as the first diagnosis. After 3 months and 6 months of chronic myocardial infarction (CMI) phase, one CMR was performed. On the same period with age and sex matching, a total of 26 cases of healthy volunteers and outpatient with non-specific chest pain and CMR examination without abnormality as control group. Plain scan included Cine, T2-weighted (STIR), and native T1/T2 mapping. The enhanced scan included perfusion, late gadolinium enhancement, post-T1 mapping. The changes of myocardial quantitative parameters before and after myocardial infarction were compared. Receiver operator characteristic curves (ROC curve) were developed to evaluate, compare, and distinguish the changes in the AMI group and the CMI group after 6 months.Results:Pre-enhanced T1 value, T2 value and extracellular volume (ECV) of AMI group were significantly higher than those of control group [pre-enhanced T1 value (ms): 1 438.7±173.4 vs. 1 269.2±42.3, pre-enhanced T2 value (ms): 49.8±9.3 vs. 21.7±4.0 , ECV (%): 33.2±10.2 vs. 27.2±2.1, all P < 0.05]. ECV was significantly higher in AMI (%: 33.2±10.2 vs. 27.2±2.1), but stabilized after 3 months (%: 33.2±10.2 vs. 32.4±5.1), and after 6 months later (%: 27.7±4.9 vs. 32.4±5.1), there were no significant difference (all P > 0.05). Pre-enhanced T1 and T2 values were significantly higher in AMI, lower after 3 months, but significantly decreased after 6 months [pre-enhanced T1 values (ms): 1 438.7±173.4 vs. 1 272.1±25.2, pre-enhanced T2 values (ms): 49.8±9.3 vs. 29.0±4.0, all P < 0.05]. The ROC curve showed that the specificity of pre-enhanced T1 and T2 values between AMI and CMI were 100%, and the sensitivity were 72.7%, 100%, respectively, pre-enhanced T1 and T2 value could be better distinguish between AMI and CMI diagnosis method. Conclusion:T1 mapping and T2 mapping with ECV can clearly diagnosis ischemic cardiomyopathy, especially pre-enhanced myocardial T1 and T2 values which is non-invasive diagnosis method of AMI, and can distinguish AMI or CMI, has a great significance to the patient's clinical treatment and follow-up.