A Preliminary Study Of Cardiac Magnetic Resonance Feature Tracking Technique For Evaluating Left Ventricular Myocardial Strain In Hypertrophic Cardiomyopathy

Objective:In this study,cardiac magnetic resonance feature tracking(CMR-FT)was used to compare and analyze the cardiac function and left ventricular myocardial strain in patients with hypertrophic cardiomyopathy(HCM)and a normal control group.To explore the relationship between myocardial strain and myocardial fibrosis,and to evaluate the value of myocardial strain in the evaluation of left ventricular systolic function in hypertrophic cardiomyopathy.Methods:Collected Forty-three HCM patients and twenty healthy volunteers diagnosed in our hospital,and CMR was performed on 3.0 T scanner with cine sequence scan and Late gadolinium enhancement.According to whether HCM patients have delayed enhancement,they are divided into two subgroups,LGE(+)and LGE(-).Using CVI 42 software to process and analyze the HCM group and the control group,and recording the baseline data of all subjects’ left ventricular end-systolic volume,left ventricular end-diastolic volume,left ventricular myocardial mass,stroke volume,left ventricular ejection fraction,cardiac output,etc.The global radial strain,global circumferential strain and global longitudinal strain of all subjects were measured and compared,as well as the radial strain,circumferential strain and longitudinal strain values of each cardiac segment(AHA 16 segment model).The independent sample t-test was used to compare the differences in baseline indicators between the HCM group and the control group,and variance analysis was used to compare the differences in global and segmental myocardial strain values between the two HCM subgroups and the control group.Results:1.General information:There were 43 patients in the HCM group,including 25 patients with LGE(+),18 patients with LGE(-),and 20 patients in the control group.There was no statistical significance in age and gender between HCM patients and the control group.2.Cardiac function index parameters:LVEF of HCM group and control group were both greater than 50%,and there were no statistical significance in LVEF,LVEDV,LVESV,CO and SV between HCM group and control group(P>0.05).LVM in HCM group was higher than control group,and the difference was statistically significant(P<0.01).3.Comparison of left ventricular global strain parameters:All subjects were successfully analyzed by CMR-FT technique for left ventricular myocardial strain.Compared with the control group,GRS,GCS and GLS of left ventricle in HCM were decreased,the difference was statistically significant(P<0.05),and the difference between LGE(+)and LGE(-)was also statistically significant(P<0.05).4.Left ventricular segmental strain parameters:The analysis of each segment in HCM group and control group showed that the strain values of theleft ventricular basal inferior wall,basal anterior wall,middle inferior wall were relatively high,while theleft ventricularanterior basal septum,basal inferior wall septum,middle anterior septum,and middle inferior wall septum were relatively low,that is,the strain value of the left ventricular free wall is higher,and the strain value of the ventricular septum is lower.Compared with the control group,the strain values of all segments in HCM group were decreased,with statistical significance(P<0.05).Compared with LGE(-),GRS in left ventricular segments 2,7,8,and 9 have statistically significant differences(P<0.05),and statistically significant differences in the 2,3,7,8,9,10,13 and 14 segments of the left ventricular in GCS(P<0.05),with statistical significance in the 2,3,7,8,9 and 14 segments of the left ventricular in GLS(P<0.05).It can be found that compared with the LGE(-)group,the LGE(+)group showed significant differences in the myocardial strain values in the basal,middle and apical anterior septum,posterior septum,and inferior wall,while there was no significance in the remaining cardiac segments between the two groups,Among them,the myocardial segments with statistical differences in GCS are the most.Conclusion:1.With left ventricular ejection fraction preserved,the myocardial strain of global and segmental of left ventricle in patients with HCM were significantly lower than those in healthy volunteers.The myocardial strain parameters obtained by CMR-FT technique are helpful for early detection of impaired cardiac systolic function in patients with HCM.2.Regardless of the presence or absence of delayed enhancement,the strain value of the left ventricular myocardium in HCM patients is reduced,indicating that the systolic function of the left ventricular myocardium in patients with hypertrophic cardiomyopathy had been impaired before the fibrosis changes occurred.Therefore,the early assessment of cardiac function by myocardial strain is significantly better than delayed enhancement analysis.3.Compared with the LGE(-)group,the myocardial strain values of the LGE(+)group were significantly reduced,especially in the ventricular septum,among which GLS could detect myocardial systolic dysfunction earlier,and the decrease of GCS was most significant in the segment of the myocardium with delayed enhancement.