磁共振特征追踪技术定量左心室应变与急性STEMI后微血管阻塞的关系

目的 采用心脏磁共振特征追踪技术(CMR-FT)量化急性ST段抬高型心肌梗死(STEMI)患者急性期左心室心肌应变及心功能改变，探讨其检测心肌梗死伴微血管阻塞(MVO)的可行性。方法 收集78例急性STEMI患者(梗死组)和10名健康志愿者(对照组)的CMR动态电影序列图像及钆对比剂延迟强化成像(LGE)资料。采用CMR-FT分析电影序列图像左心室整体心肌应变整体峰值径向应变(GPRS)、周向应变(GPCS)及纵向应变(GPLS)]、节段心肌应变节段峰值径向应变(PRS)、周向应变(PCS)及纵向应变(PLS)]和左心室心功能左心室射血分数(LVEF)、左心室舒张末期容积指数(LVEDVi)、左心室收缩末期容积指数(LVESVi)及心脏指数(CI)]。根据LGE评估是否存在MVO，将患者分为MVO组(n=50)和无MVO组(n=28)，将其左心室心肌节段分为MVO节段组(n=173)和无MVO节段组(n=1075)。根据左心室节段应变绘制ROC曲线，并计算AUC值。结果 梗死组左心室GPRS、GPCS、GPLS、PRS、PCS及PLS与对照组差异有统计学意义（P均<0.001）；梗死组左心室LVEF、LVEDVi、LVESVi与对照组差异有统计学意义（P均<0.05）；MVO节段组在左心室PRS、PCS、PLS与无MVO节段组差异有统计学意义（P均<0.001）；PRS和PCS取24.65%和-14.05%时检测MVO的敏感性、特异性、AUC分别为89.0%、60.6%、0.816和75.7%、75.9%、0.818。结论 采用CMR-FT测量左心室心肌节段峰值应变可检测急性STEMI患者是否发生MVO，为临床对急性STEMI患者进行早期风险分层管理提供了无创、便捷的新方法。

Correlating microvascular obstruction of acute STEMI to left ventricular strain by cardiovascular magnetic resonance feature tracking imaging

Objective To quantify the changes of left ventricular (LV) myocardial strain and cardiac function of patients with acute ST segment elevation myocardial infarction (STEMI) with cardiac MR feature tracking (CMR-FT), so as to explore its feasibility of detecting myocardial infarction with microvascular obstruction (MVO). Methods CMR motion picture sequence images and late gadolinium enhancement (LGE) data of 78 patients with acute STEMI (infarct group) and 10 healthy volunteers (control group) were collected. CMR-FT was used to analyze film sequences images of left ventricular global strains (global peak radial strain GPRS], global peak circumferential strain GPCS], global peak longitudinal strain GPLS]), segmental strains (peak radial strain PRS], peak circumferential strain PCS], peak longitudinal strain PLS]) and cardiac function (left ventricular ejection fraction LVEF], left ventricular end-diastolic volume index LVEDVi], left ventricular end-systolic volume index LVESVi] and cardiac index CI]). Patients with acute STEMI were divided into MVO group (n=50) and non-MVO group (n=28), while their LV segments were divided into MVO segment group (n=173) and non-MVO segment group (n=1075) based on LGE assessment. The LV segment strain was plotted as ROC curve, and AUC value was calculated. Results There were statistically significant differences of LV GPRS, GPCS, GPLS, PRS, PCS and PLS (all P<0.001), also of LVEF, LVEDVi and LVESVi between infarct group and control group (all P<0.05). There were statistically significant differences of LV PRS, PCS and PLS between MVO segment group and non-MVO segment group (all P<0.001). The sensitivity, specificity and AUC of detecting MVO with PRS and PCS respectively at 24.65% and -14.05% were 89.0%, 60.6%, 0.816 and 75.7%, 75.9%, 0.818, respectively. Conclusion Measurement of LV segmental strain with CMR-FT can detect MVO of patients with acute STEMI, therefore providing a non=invasive and convenient new method for early risk management in patients with acute STEMI.