磁共振特征追踪技术在急性心肌炎中的临床应用

Clinical aplication of magnetic resonance feature tracking technique in acute myocarditis

目的:应用心脏磁共振特征追踪(CMR-FT)技术评价急性心肌炎(aMC)患者左心室心肌应变功能,探讨应变参数与左心室射血分数(LVEF)的相关性。方法:回顾性搜集49例aMC患者和32例健康志愿者(对照组)电影序列心脏MRI图像(标准两腔、三腔、四腔及短轴位),采用磁共振后处理站计算两组被试者的LVEF,并应用CMR-FT技术测量左心室各项心肌应变参数值(左心室心肌整体径向应变、周向应变和纵向应变及各向应变率)并进行组间比较,采用受试者工作特征(ROC)曲线评价左心室应变参数诊断aMC的效能,并对aMC组中收缩期和舒张期各项应变参数与LVEF的相关性进行统计学分析。结果:aMC组和对照组的心肌整体径向应变、周向应变和纵向应变值分别为26.07%±13.60%vs.38.95%±8.90%、-15.58%±5.97%vs.-20.79%±2.33%、-10.86%±5.25%vs.-15.22%±3.30%,aMC组的左心室各项应变参数值均低于对照组,差异均具有统计学意义(P<0.05)。左心室周向应变和径向应变预测急性心肌炎组的敏感度分别为77.55%和61.22%,特异度分别为75.00%和84.38%。左心室各项应变参数与LVEF之间均具有相关性,其中左心室径向应变、周向应变与LVEF呈高度相关(r=0.809、-0.904,P均<0.05)。结论:CMR-FT技术能够定量评价急性心肌炎患者左心室心肌应变功能,为临床评估aMC患者的心肌损伤程度提供参考依据,其测得的心肌应变参数和LVEF在反映心肌收缩功能受损方面具有较好的一致性。

Objective:The purpose of this study was to evaluate the left ventricular myocardial strain in patients with acute myocarditis(aMC)by use of cardiovascular magnetic resonance feature tracking(CMR-FT)technique and to investigate the correlation between strain parameters and left ventricular ejection fraction(LVEF).Methods:The images of 49 patients with aMC and 32 healthy vo-lunters(HC group)who underwent cine magnetic resonance scan on standard two-chamber view,three-chamber view,four-chamber view and short axis view were collected retrospectively.The left ventricular ejection fraction(LVEF)were calculated on the magnetic resonance post-processing station.The left ventricular myocardial strain parameters were measured by CMR-FT,including global peak radial strain(PRS),peak circumferential strain(PCS),and peak longitudinal strain(PLS)of left ventricular myocardium and the systolic and diastolic anisotropic strain rate,and their differences between aMC group and HC group were compared statistically.The receiver operating characteristic(ROC)curve was used to evaluate the efficacy of left ventricular strain parameters in diagnosis of acute myocarditis.The correlation between each strain parameter and LVEF in aMC group were analyzed statistically.Results:The left ventricular strain parameters in the aMC group were lower than those in the control group.The global peak radial strain,peak circumferential strain,peak longitudinal strain in the two groups were 26.07%±13.60%vs.38.95%±8.90%,-15.58%±5.97%vs.-20.79%±2.33%,and-10.86%±5.25%vs.-15.22%±3.30%,respectively,with statistically significant differences(all P<0.05).The sensitivity and specificity of left ventricular peak circumfe-rential strain and peak radial strain in distinguishing acute myocarditis group and control group were 77.55%and 61.22%,75.00%and 84.38%,respectively.There were certain correlation between left ventricular strain parameters and LVEF,among which the left ventricular peak radial strain and peak circumfe-rential strain were highly correlated with LVEF(r=0.809 and-0.904,both P<0.05).Conclusion:CMR-FT can quantitatively evaluate the left ventricular myocardial strain function in patients with acute myocarditis and provide reference for clinical evaluation of the degree of myocardial injury in patients with aMC.Myocardial strain can better reflect impaired myocardial contractile function which is the same as LVEF.