心脏MRI评估心肌梗死存活心肌及其PCI术后心功能转归的相关性

Correlation between myocardial infarction activity assessed by cardiac magnetic resonance imaging and the evolution of cardiac function after PCI

目的:探讨心脏磁共振成像在评估心肌梗死心肌活性及其PCI术后心功能转归的相关性。方法:回顾性分析2016年7月~2018年12月30例行PCI术后的具有完整临床和影像资料的心肌梗死(MI)患者,并于术前及术后6个月行心脏磁共振及超声心动图检查,利用MRI工作站后处理软件测量左室功能相关参数;PCI术前CMR钆对比剂延迟强化(late gadolinium enhancement,LEG)的左室透壁程度与其术后6个月超声心动图像的左心室壁运动程度作为判断存活心肌的标准进行对比。结果:30例中共有193个左室节段异常,其中术前CMR-LEG有存活心肌121个,非存活心肌72个;PCI术后6个月超声心动图发现在其术前CMR-LEG发现的193个左室异常节段中有125个节段为存活心肌,68个节段为非存活心肌;二者相比较得出CMR-LEG测定存活心肌的灵敏度和特异度分别为92.0%和91.1%。左室壁非存活心肌范围越大,则其室壁运动能力恢复越差,二者呈负相关(r=0.416,P<0.05);CMR-LEG区域首过灌注时间较正常心肌区域明显延长,差异具有统计学意义(t=5.191,P<0.05)。结论:心脏磁共振成像能评估心肌梗死心肌活性,反映存活心肌的范围,为临床选择治疗方案及判断预后提供影像学依据。

Objective: To investigate the feasibility of cardiac magnetic resonance imaging(MRI)in the assessment of myocardial infarction activity and the evolution of cardiac function after PCI.Methods:The clinical and imaging data of 30 patients with ischemic heart disease from July 2016 to December 2018 were analyzed retrospectively.All of the above patients received percutaneous coronary intervention(PCI),and cardiac magnetic resonance and echocardiography were performed before the operation,within 7 d and 6 month after the operation.The parameters related to left ventricular function,the area of delayed myocardial enhancement,the time of myocardial first pass perfusion,the percentage of myocardial area of delayed enhancement to the area of regional wall motion abnormalities were measured on the MRI images,and the corresponding ADC values were measured on DWI imagesby softwarepost-processing.Six months after PCI,the improvement of left ventricular function on echocardiography was used as the gold standard to judge viable myocardium.The sensitivity and specificity of MRI in detecting viable myocardium were calculated,and its value in predicting the activity of infarcted myocardium was analyzed.At the same time,we compared the changes of ADC value on DWI image after PCI,and analyzed the clinical value of DWI image in evaluating the changes of cardiac function after PCI.Results:The results showed that there were 193 segments with abnormal left ventricular wall motion,121 of which were judged as viable and 72 as non viable by delayed enhancement,and 125 of which were judged as viable and 68 as non viable by echocardiography 6 month after PCI.The results showed that the sensitivity and specificity of delayed enhancement were 92.0%and 91.1%respectively.The larger the area of delayed enhancement was,the worse the ability of wall movement was,and there was a negative correlation between them(P<0.05).The first perfusion time of delayed enhancement area of MR was significantly longer than that of normal myocardium,which were(4.85±1.51)s and(3.79±1.73)s,respectively,with statistical differences The ADC value measured 6 m after PCI was significantly higher than that within 7 days after PCI,the difference was statistically significant(P<0.05).Conclusion: MRI has great clinical value in identifying the activity of infarcted myocardium,and can accurately detect the viable myocardium by delayed imaging.DWI imaging can better evaluate the cardiac function of patients after PCI,and has a certain clinical application prospect.