| Objective: 1.5T cardiac magnetic resonance imaging(CMRI)technique was used to detect and assess the structure,function and myocardial fibrosis of left ventricle in patients with dilated cardiomyopathy(DCM),and to analyze the relationship between myocardial fibrosis and left ventricular structure and cardiac function.Materials and Methods:62 patients with DCM and 30 healthy controls were enrolled,and then underwent cardiac magnetic resonance imaging.Left ventricular structure and function parameters were measured as follows: left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),left ventricular ejection fraction(LVEF),left ventricular stroke volume(LVSV),left ventricular cardiac output(LVCO),left ventricular myocardial mass(LVMM),left ventricular peak ejection rate(LVPER),left ventricular peak filling rate(LVPFR),left ventricular time to peak ejection rate(LVTPER),left ventricular time to peak filling rate(LVTPFR),left ventricular end-diastolic dimension(LVEDD),left ventricular end-systolic diameter(LVESD),left ventricular end-diastolic sphericiry index(LVSId),and left ventricular end-systolic sphericiry index(LVSIs).The LVEDV,LVESV,LVSV,LVCO,LVMM,LVEDD,and LVESD values divided by the body surface area were calibrated with LVEDVI,LVESVI,LVSVI,LVCI,LVMMI,LVEDDI,and LVESDI.The late gadolinium enhancement(LGE)imaging technique was used to determine whether the left ventricle had myocardial fibrosis.Patients in DCM group were divided into LGE(+)group(32 cases)and LGE(-)group(30 cases)according to the presence or absence of late gadolinium enhancement(LGE).The following analysis were performed: 1.The differences in structural and functional parameters between the DCM group and the control group,and between the LGE(+)group,the LGE(-)group and the control group were compared.The data analysis was performed using the Chi-square test,independent sample t test,and analysis of variance;2.Through the ROC curves of the structure and function parameters,the area under the curve,the optimal threshold,the sensitivity and the specificity of each structure and function parameters were obtained to evaluate its diagnostic value for DCM;3.To analyze the specific situation of left ventricular myocardial fibrosis in patients with DCM,that is,to observe the location of LGE,morphological features and the number of involved segments;4.Pearson or Spearman correlation was used to analyze the relationship between LGE(+)segment number and New York Heart Function Class,left ventricular structure and functional parameters.When P<0.05,the difference was considered statistically significant.Results: 1.LVEDDI,LVESDI,LVSId,LVSIs,LVEF,LVEDVI,LVESVI,LVMMI,LVPER,LVTPER,and LVPFR in the DCM group were significanttly different from those in the control guoup(P<0.05).The values of LVCI and LVTPFR in the DCM group were not significantly different from those in the control guoup(P>0.05).LVEDDI,LVESDI,LVSId,LVSIs,LVEF,LVEDVI,LVESVI,LVMMI,LVPER,LVTPER,and LVPFR in DCM LGE(+)group and LGE(-)group were significantly different from those in healthy control group(P<0.05).There was no significant difference in LVSVI,LVCI,and LVTPFR between the LGE(+)group and LGE(-)group and the healthy control guoup(P(29)0.05).LVEDDI,LVESDI,LVEF,LVEDVI,LVESVI,LVMMI,LVPER,LVTPER,and LVPFR were significantly different between the LGE(+)group and the LGE(-)group(P<0.05).LVSId,LVSIs,LVSVI,LVCI,and LVTPFR values for comparison,the difference was not statistically significant between the LGE(+)group and the LGE(-)group(P(29)0.05).2.The area under the curve obtained from left ventricular structural and functional parameters of patients with DCM was 0.813 to 1.0,suggesting that the structural and functional parameters all have medium to high diagnostic value for DCM.3.Thirty-two of 62 patients with DCM developed left ventricular myocardial fibrosis,with a cumulative enhancement of 201 segments,accounting for 36.9%(201/544).The most commonly affected sites for delayed enhancement are the anterior wall(segment 2)and posterior wall(segment 3)of the basal segment.Of the 32 patients with DCM LGE(+),25 cases showed linear enhancement of muscular wall,accounting for 78.1%(25/32);3 cases were focal laminar enhancement,accounting for 9.4%(3/32),and 4 diffuse enhancement occurred,accounting for 12.5%(4/32).4.According to Pearson or Spearman correlation analysis,there was a positive correlation between the number of LGE(+)segments and the grade of cardiac function(r=0.455,P=0.009).The number of LGE segments was positively correlated with left ventricular structure and LVESDI,LVEDVI,LVESVI,LVMMI and LVTPER(r=0.379,0.434,0.377,0.508,0.384,P=0.032,0.013,0.034,0.003,0.030),which was negatively correlated with LVEF,LVPFR(r=-0.526,-0.407,P=0.002,0.021).The number of LGE segments was not related to LVEDDI,LVSId,LVSIs,LVSVI,LVCI,LVPER,and LVTPFR(all P(29)0.05).Conclusion: 1.5T CMR has important value in assessing the structural and functional changes of left ventricle in patients with DCM,as well as qualitative and quantitative detection of myocardial fibrosis.The more segments of myocardial fibrosis represented by LGE(+)in DCM patients,the higher the cardiac functional class,the lower the left ventricular systolic and diastolic function,and the more obvious the used for early clinical diagnosis and treatment of DCM,as well as assessment of its prognosis. |
