To Study The Application Of Magnetic Resonance T1mapping Technology In The Characteristics Of Myocardial Tissue In Patients With Dilated Cardiomyopathy

Objective: To explore the application value of T1 mapping technique of 3.0T cardiac magnetic resonance(CMR)imaging in the whole left ventricle,each region and each segment myocardial tissue characteristics of dilated cardiomyopathy(DCM)patients,and to explore its diagnostic efficacy of the initial T1 value.Methods: Clinical and CMR data of 20 DCM patients(DCM group)and 25 normal patients(control group)admitted to the First People’s Hospital of Jining City from October 2021 to December 2022 were collected.The scanning sequences included film sequence,initial T1 mapping sequence and delay enhancement sequence.Left ventricular cardiac function parameters were obtained by left ventricular short axis movie sequence.Including left ventricular ejection fraction(LVEF),left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),left ventricular stroke volume(LVSV),left ventricular cardiac output(LVCO),and left ventricular myocardial mass(LVMM).The initial T1 values of all myocardium segments of the left ventricle and the initial T1 values of the left ventricular myocardium were obtained by T1 mapping sequence.According to the existence of late gadolinium enhancement(LGE)in the myocardium of DCM patients,the DCM group was divided into DCM-LGE(+)group and DCM-LGE(-)group,and DCM-LGE(+)segment group and DCM-LGE(-)segment group.Then,independent sample t test or Mann-Whitney U test were used to compare whether there were differences in the initial T1 values of the left ventricular in total,each segment and each part among DCM group,DCM-LGE(+)group,DCM-LGE(-)group and control group.The initial T1 values were compared between DCM-LGE(+)segment group,DCM-LGE(-)segment group and control group.Receiver operating characteristic(ROC)curve of initial T1 value was plotted to evaluate its diagnostic efficacy for DCM patients.Results:(1)There were no significant differences in age,sex,height,weight,body mass index(BMI)and heart rate between the DCM group and the control group(P>0.05);LVEF and LVSV in DCM group were lower than those in control group,while LVEDV,LVESV and LVMM in DCM group were higher than those in control group,and the difference was statistically significant(P<0.05).There was no significant difference in LVCO between the two groups(P>0.05).(2)The initial T1 values of the whole left ventricle,each segment and each region of the myocardium were compared among DCM group,DCM-LGE(+)group,DCM-LGE(-)group and control group,The initial T1 values of 1-16 segment,basal segment,middle segment,apical segment and total left ventricular myocardium in the DCM group were significantly higher than those in the control group(P<0.05).The initial T1 values of the 2,3,4,5,6,8,9,10,11,12,13,14,15,16 segments,basal segments,middle segments,apical segments and total left ventricle myocardium in the DCM-LGE(+)group were significantly higher than those in the control group(P<0.05).The initial T1 values of 1,2,6,8,9,10,11,12,13 segments,basal segments,middle segments and total left ventricular myocardium in the DCM-LGE(-)group were significantly higher than those in the control group(P<0.05).The initial T1 values of 13,14 segments and apical segments in the DCM-LGE(+)group were significantly higher than those in the DCM-LGE(-)group(P<0.05).(3)The comparison of initial T1 values among DCM-LGE(+)segment group,DCM-LGE(-)segment group and control group showed that the initial T1 value of DCM-LGE(+)segment group was higher than that of control group(P<0.05),the initial T1 value of DCM-LGE(+)segment group was higher than that of DCM-LGE(-)segment group(P<0.05),the initial T1 value of DCM-LGE(-)segment group was higher than that of control group(P<0.05).(4)ROC curve was used to analyze the diagnostic efficiency of initial T1 value for DCM.The area under ROC curve of initial T1 value for distinguishing DCM group from control group was 0.799,P<0.001,the optimal cut-off value was 1218.1ms,sensitivity was 71.8%,specificity was 78.1%.The area under ROC curve for distinguishing DCM-LGE(+)segment from control group by initial T1 value was 0.832,P<0.001,the optimal cut-off value was 1237.65 ms,sensitivity was 73.5%,specificity was 86%.The area under ROC curve for distinguishing DCM-LGE(-)segment group from control group was 0.774,P<0.001,the optimal cut-off value was 1221.2ms,sensitivity was 65.7%,specificity was 79%.The area under ROC curve for distinguishing DCM-LGE(+)segment from DCM-LGE(-)segment was 0.631,P<0.001,the optimal cut-off value was 1315.55 ms,sensitivity was 45.1%,specificity was 81.1%.Conclusion: 1.CMR T1 mapping can noninvasively and quantitatively evaluate the global,regional and segmental myocardial tissue characteristics of the left ventricle in patients with DCM.The initial T1 values of the global,regional and segmental left ventricle in patients with DCM are increased,it is speculated that the apical myocardium is the latest involved in the development of myocardial damage in DCM patients.2.The initial T1 value of CMR T1 mapping can early detect myocardial abnormalities(myocardial edema or fibrosis)in DCM patients before traditional LGE.3.The initial T1 value has a good diagnostic efficacy value for patients with DCM.The optimal cut-off value for predicting LGE in patients with DCM based on the initial T1 value is 1315.55 ms,which can provide a new diagnostic idea for the evaluation of myocardial tissue characteristics in DCM patients with contraindications to contrast media,and has high clinical application value.