Evaluation Of Left Ventricular Strain In Patients By Cardiac MRI Tissue Tracking

Background and purpose : EF is often used as an index to evaluate cardiac systolic function in clinic.However,as an index of global function measurement,most of the changes of EF occur in the later stage of heart disease,which can not identify early cardiac dysfunction and evaluate local myocardial injury.So EF can not fully reflect the cardiac systolic function of patients.At present,as another index to evaluate cardiac function,myocardial deformation has great advantages in detecting early myocardial injury and evaluating myocardial local injury.In this study,cardiac magnetic resonance tissue tracking(CMR-TT)was used to measure the myocardial deformation parameters of the whole left ventricle,basal segment,middle segment and apical segment of the two groups of clinical patients to evaluate the differences of these parameters and explore the reasons.Methods: From January 2018 to May 2019,77 patients were admitted to Songjiang Branch of Shanghai First People’s Hospital.According to EF,55 patients with EF≥55% and 22 patients with EF<55%.the group of EF≥55%were divided into EF reserved cardiomyopathy group and noncardiomyopathy group according to clinical data.The patients were divided into three groups according to the type of disease,including 28 patients with arrhythmia cardiomyopathy,26 patients with non-arrhythmia cardiomyopathy and 23 patients with non-cardiomyopathy.All patients were scanned with 3.0 T CMR and imaged with SSFP of steady-state free precession sequence.The endocardial and epicardial positions of the left ventricle were semi-automatically delineated by the CMR-TT technique provided by the CVI 42 software,an d the routine cardiac function parameters of the left ventricle and the longitudinal,circumferential and radial myocardial strain,strain rate,displacement,displacement velocity and left ventricular torsion angle of the whole l eft ventricle,basal segment,middle segment and apical segment of the left ventricle were obtained.The differences of clinical data,left ventricular routine cardiac function parameters and left ventricular myocardial deformation parameters between EF≥ 55% group and EF <55% group,EF retained cardiomyopathy group and non-cardiomyopathy control grou p were tested by independent sample t-test,chi-square test or rank sum test.Results:(1)Compared with the EF ≥ 55% group,the left ventricular overall myocardial strain,partial direction myocardial displacement,and peak velocity decreased in the EF <55% group.The difference was statistically significant.(2)Compared with the non-cardiomyopathy control group,the left ventricular overall myocardial strain and displacement,left ventricular overall local velocity and left ventricular local myocardial strain,displacement,and velocity peak of the EFpreserved cardiomyopathy group decreased,the difference was statistically significant.(3)Compared with the non-arrhythmic cardiomyopathy group,the left ventricular local myocardial deformation parameters of patients in the arrhythmic cardiomyopathy group were only statistically different in some directions.Conclusion: 1.CMR-TT can detect early cardiac dysfunction and local myocardial injury before abnormalities of EF.2.Among the three deformation parameters of left ventricular strain,displacement and velocity,the clinical value of m yocardial strain is the highest.