心肌T1、T2 mapping技术和细胞外容积分数对急性心肌梗死的诊断价值

T1,T2 mapping and extracellular volume diagnostic value in patients with acute myocardial infarction

目的探讨心肌T1、T2 mapping技术和细胞外容积分数(extracellularvolume fraction,ECV)在急性心肌梗死中的诊断价值。方法采用西门子1.5T Aera磁共振扫描仪对24例急性心梗的患者行心肌T1、T2 mapping序列和延迟灌注检查,将扫描图像输入到syng MR D13后处理工作站,在T1、T2 mapping图手动画取延迟强化节段兴趣区并计算强化前后T1、T2值及血池增强前后T1值,以远隔未强化区域为对照组,同样方法计算该域强化前后T1、T2值及血池T1值,计算两组的ECV,采用t检验和ROC曲线进行分析。结果急性心肌梗死区域初始T1值(1320.0±28.4)ms大于远隔未强化区域初始T1值(1196.8±27.0)ms(P<0.001),急性心肌梗死区域T1值下降较远隔未强化区域更明显,两者ECV分别为(38.7±2.1)%、(24.8±2.5)%(P<0.001);急性心肌梗死区域T2值为(93.3±6.6)ms大于远隔未强化区域T2值(80.7±6.7)ms(P<0.001);各参数值ROC曲线下面积(AUC)分别为0.812、0.840、0.875、0.819,均具备较好的灵敏度、特异度和准确度。从ROC曲线图中可看出ECV值对于心肌梗死的诊断效能较其他指标高。结论心肌T1、T2 mapping技术和ECV在识别及定量急性心肌梗死具有较高价值。

Objective To explore T1,T2 mapping and extracellular volume diagnostic value in patients with acute myocardial infarction.Methods 24 patients with acute myocardial infarction were performed T1,T2 mapping sequence and delayed perfusion examination by a Siemens 1.5 T Aera MRI scanner.The images were input to the syng MR D13 post⁃processing workstation,manually drawn the area of interest in the delayed⁃enhanced segment,and then the T1 values before and after,T2 Values and reinforcement of area of interest and the blood pool were calculated.With Separate the unreinforced section did not strengthen the area for the control group,the same method was used to calculate the T1 values,T2 values and blood pool T1 values.The extracellular fractions were calculated for both groups.T⁃test and the ROC curve were used to compare the differences between the two groups(P<0.05).Results The initial T1 value(1320.0±28.4)ms in the delayed enhancement was larger than that in the Separate the unreinforced areas(1196.8±27.0)ms(P<0.05).The value of T1 in the delayed enhancement region was declining more obvious than that in the enhancement region.The extracellular volume fraction were(38.7±2.1)%and(24.8±2.5)%respectively(P<0.05).The area under the ROC curve of each parameter was 0.812,0.840,0.875,0.819,and it has good sensitivity,specificity and accuracy.From the ROC curve,it can be seen that the diagnostic efficiency of ECV for myocardial infarction is higher than that of other parameters.Conclusion T1,T2 mapping and ECV have a high value in identifying and quantifying acute myocar⁃dial infarction.