Application Of Cardiovascular Magnetic Resonance T1 Mapping And CMR-FT Techniques For The Quantitative Analysis Of Hypertensive Heart Disease

Objective To analyze the correlation between diffuse myocardial fibrosis and myocardial strain injury in patients with HHD by comparing the variability of T1 mapping parameters and myocardial strain parameters between hypertensive heart disease(HHD)and controls by the T1 mapping technique of cardiovascular magnetic resonance(CMR)and the characteristic tracking(CMR-FT)technique,and to analyze the best quantitative parameters for the diagnostic efficacy of HHD.To assess the extent of diffuse myocardial fibrosis and myocardial strain injury in the left ventricle in patients with HHD.Methods Sixty-two patients with HHD and 28 healthy controls with normal blood pressure matched for age range(defined as group A)were selected,all of whom were processed by the cardiac post-processing analysis software CVI42 after 3.0T CMR scan,and the LV myocardium was divided into three levels: basal,intermediate,and apical segments.the HHD group was divided according to the end-diastolic LV wall thickness(EDWT)values,with EDWT≥12 mm as The HHD group was divided into three groups according to the end-diastolic LV wall thickness(EDWT)value,EDWT≥12mm for HHD with LV hypertrophy(set as group B)and EDWT <12 mm for HHD without LV hypertrophy(set as group C),and then divided into three groups according to different LVEF,LVEF<40%(set as group D),40% ≤LVEF<50%(set as group E)and LVEF ≥50%(set as group F).The differences in LV function,T1 mapping,and myocardial strain parameters were compared between the groups.Two-by-two comparisons between groups were performed by the LSD-t method,and Kruskal-Wallis H test was used for comparisons between multiple groups.Linear correlation was applied to analyze the correlation between left ventricular T1 mapping and myocardial strain parameters in HHD patients.The diagnostic efficacy of T1 mapping parameters and myocardial strain parameters for HHD was analyzed using subject operating curves(ROC curves).Results(1)HHD was grouped according to whether the myocardium was hypertrophic or not.compared with group A,ejection fraction(LVEF)and cardiac index(CI)were decreased in the HHD group,and left ventricular mass index(LVMI)and end-diastolic volume ratio(M/V)were increased in the HHD group.comparing between groups,LVEF was lower in group B than in group C,and LVMI and M/V were higher than in group C.extracellular volume(ECV)and extracellular volume index(i ECV)of the overall myocardium and each segment of the myocardium were increased in the HHD group.The absolute values of radial strain(RS),circumferential strain(CS),and longitudinal strain(LS)in the overall myocardium and in each segment of the myocardium were decreased in the HHD group,and the absolute values of RS and LS in the overall and in each segment of the myocardium were lower in group B than in group C and in group C than in group A.The differences were statistically significant.The differences were statistically significant(P < 0.05).(2)HHD was grouped according to LVEF,and compared with group A,the maximum LV wall thickness(LVMWT)and LVMI increased and CI values decreased in group D.The overall myocardial ECV was significantly higher in HHD patients than in group A.The ECV and i ECV in group D were significantly higher than in the other three groups,and the i ECV in group E was significantly higher than in groups F and A.The RS,CS,and LS of the overall myocardium and each segment of the myocardium in the HHD group were The absolute values of LS were reduced in the HHD group as a whole and in each section of the myocardium.In the comparison between groups,the absolute values of RS,CS,and LS were reduced in groups D,E,and F as the LVEF values were reduced,and the difference was statistically significant(p < 0.05).(3)Linear correlation analysis showed that ECV in the HHD group had a linear positive correlation with overall radial strain(GRS)(r=0.432,p<0.001),a linear negative correlation with overall circumferential strain(GCS)(r=-0.447,p<0.001),and a linear negative correlation with overall longitudinal strain(GLS)(r=-0.581,p< 0.001).(4)The ROC curve showed that the diagnostic efficacy of GLS was the highest when differentiating the HHD group from the A group(AUC 0.945,sensitivity and specificity 96.77% and 82.14%,respectively),and the diagnostic efficacy of GRS was the highest when differentiating the HHD group with reduced LVEF(LVEF <50%)from the group with normal LVEF(LVEF ≥50%)(AUC 0.969).The sensitivity and specificity were 94.74% and 91.67%,respectively),and the diagnostic efficacy of ECV was the highest(AUC of 0.793,sensitivity and specificity of 81.25% and 76.67%,respectively)when differentiating the LVH group from the non-LVH group in HHD.Conclusion The ECV and i ECV of T1 mapping imaging can be used as quantitative imaging parameters for diagnosing diffuse myocardial fibrosis in HHD patients,and the GRS,GCS,and GLS of CMR-FT technique can all be used as quantitative imaging parameters for assessing myocardial motion injury in the left ventricle in HHD patients at an early stage,and myocardial fibrosis and myocardial strain injury in HHD are correlated,and CMR’s T1 mapping technique and CMR-FT technique provide an imaging basis for diffuse myocardial fibrosis and early myocardial strain injury in HHD,and provide clinical advancement to intervene in early cardiac changes in HHD,and then achieve improved ventricular remodeling in HHD.