Evaluation Of Left Ventricular Global Myocardial Strain With Acute Myocarditis By Cardiac Magnetic Resonance Tissue Tracking

Objective: To evaluate left ventricular global myocardial strain and its correlation with left ventricular ejection fraction(LVEF)and delayed enhancement(LGE)segments with acute myocarditis(ACM)by cardiac magnetic resonance tissue tracking(CMR-TT).To explore the predictive value of left ventricular global myocardial strain with ACM(CMR negative).Methods: From January 2016 to August 2018,35 patients with acute myocarditis hospitalized in Sichuan Provincial People's Hospital were enrolled as case group,and 27 healthy volunteers matching sex and age were enrolled as control group.According to the imaging characteristics of CMR,the case group was divided into positive group 21 cases and negative group 14 cases.All subjects performed cardiac magnetic resonance imaging.Left ventricular function parameters EF?End Systolic Volume(ESD)?End Diastolic Volume(EDV)?Stroke Volume(SV)?Cardiac Output(CO)?Cardiac Index(CI)were measured by Argus post-processing software,left ventricular global myocardial strain parameters were measured by CVI42 software: global radial strain peak(GRSP)?circumferential strain peak(GCSP)?longitudinal strain peak(GLSP)?According to the 17 segments of left ventricular myocardium of the American Heart Association,the number of segments with delayed enhancement of left ventricular myocardium were observed;the clinical and CMR imaging characteristics of ACM were collected.Quantitative data between the two groups were compared by t test,and non-parametric test.Receiver Operating Characteristic curve was used to analyze the different parameters between the two groups,and to calculate the best critical value,Area Under The Curve and diagnostic efficiency of each parameter for ACM.Spearman correlation was used to analyze the correlation between left ventricular global myocardial strain and LVEF and the number of LGE segments.To analyze the consistency of global left ventricular myocardial strain between observers and within observers.Results: Of the 35 cases in the case group,21 cases were LGE positive,There were 142 LGE segments.The most common segment of LGE was lateral wall,followed by interventricular wall,mainly subepicardial delayed enhancement.Compared with the control group,the GRSP,GCSP and GLSP in the case group were significantly reduced,the differences were statistically significant(P < 0.05).Age,BSA,EF,EDV,ESD,SV,CO,CI were not statistically significant(P > 0.05).Compared with the control group,ACM in CMR negative group decreased significantly in GRSP and GCSP(P < 0.05),but there were no significant differences in Age,BSA,EF,EDV and ESD?GLSP(P > 0.05).Recorrelation analysis: GRSP,GLSP,GCSP in case group were strongly correlated with LVEF(r=0.709,P<0.001;r=-0.746,P<0.001;r=-0.669,P<0.001);GRSP,GLSP,GCSP in case group were strongly correlated with LGE segment number(r=-0.611,P<0.001;r=0.624,P<0.001;r=0.445,P<0.001).ROC curve analysis showed that GRSP,GCSP and GLSP had certain predictive value for ACM.The optimal critical values were 36.67%,-18.00%,-15.46%.AUC was 0.728,0.782,0.733,respectively sensitivity and specificity were74.1%and68.6%,77.8%and71.4%,51.4% and92.6%,GRSP and GCSP had certain predictive value for ACM in the group with CMR negative,with the optimal critical values of 40.81% and-20.11%,the AUC of 0.755 and 0.786,respectively the sensitivity and specificity of 92.9%and 57.1%,92.9% and 64.3%,Left ventricular global myocardial strain was well consistent between observers and within observers.Conclusion:(1)In ACM patients,LGE is mainly located in the left ventricular lateral wall,followed by the interventricular wall,mainly in the subepicardial delayed enhancement.(2)Cardiac magnetic resonance tissue tracking technique can quantitatively assess left ventricular global strain in ACM,compared with LVEF,left ventricular global strain energy can detect early myocardial dysfunction.and it has a strong correlation with the LVEF and the number of segments of LGE,which can become a new parameter for evaluating cardiac function.(3)Left ventricular global myocardial strain has certain predictive value for ACM,especially for ACM with CMR negative;which can provides imaging basis for timely diagnosis,treatment and improvement of prognosis.