| ObjectiveTo investigate whether a correlation exists between abnormal myocardial iron status and cardiac lipid deposition as well as other biomarkers in patients with diabetic heart failure(DHF)with the technique of T2*mapping and 1H magnetic resonance spectroscopy('H-MRS).Materials and MethodsThis study was approved by local institutional review board,and all of participants' informed consent was obtained.MRI scans were performed on 17 healthy volunteers(Group 1)and 51 male patients suffering from type 2 diabetes mellitus(T2DM)around 60 years old(Group 2 and Group 3)using a Siemens 3.0 T system,which the aim was eliminating some factors that may effect the experimental results such as gender,age,hormone and so on.These 51 patients had accepted the echocardiographic tests before the MRI examination in order to represent the progressive stages of DHF.Then the patients included in this study were divided into two groups(n=26 in Group 2 and n=25 in Group 3)according to the results of left ventricular ejection fraction(LVEF)with a cut off value of 40%(LVEF in Group 2(?)40%,LVEF in Group 3<40%).There is no history of cardiovascular diseases,diabetes mellitus and other chronic diseases in the healthy volunteers at the onset of this study.All of the participants did not have claustrophobia or other MRI scan contraindications.In the meanwhile,all of their imaging data were qualified accordingly.All subjects participating in this study were examined using a 3 T system(Magnetom Skyra,Siemens Healthcare,Erlangen,Germany)using a 32-channel cardiac radiofrequency(RF)coil for signal reception and electrocardiography(ECG)for cardiac gating.All examiners are scanned in the supine position,with head advanced for MR examination.The imaging protocol included a long-axis cine sequence,T2*mapping sequence,1H-MRS sequence,short-axis cine sequence,and late gadolinium-enhancement sequence(LGE).These procedures were carried out sequentially.Using T2*mapping to evaluate myocardial iron status in a noninvasive way.While drawing the regions of interest(ROI)in T2*mapping images,it must be careful to ensure that the ROI was not beyond the myocardium and blood,epicardial fat.The trabeculated layer and epicardial border were all excluded.ROI was located on the cardiac septum in a mid-ventricular slice of the left ventricle.Using 1H magnetic resonance spectroscopy,(1H-MRS)to assess the lipid deposition.Myocardial contents were calculated as a percentage relative to water using the equation(signal amplitude of lipid/signal amplitude of water)X 100.Fasting venous blood was used to examine serum biomarkers.Two experienced cardiac radiologists measured the values separately.Differences between two groups were tested for significance using the two-tailed unpaired t-test.Comparisons across three groups were performed using the Bonferroni method.Blande-Altman analysis was used to assess intraand interobserver dependency of cardiac MRI parameters.Correlations between T2*and other factors were obtained using Pearson correlation.ResultsCardiac T2*(ms)of the three groups were 22.8±2.1,21.7± 1.8,and 18.6±1.3,respectively.The value of Group 3 was significantly lower than that of the other two groups(p<0.001).Myocardial triglyceride(%)levels differed among the three groups(Group 1,0.53 ±0.13;Group 2,1.11 ±0.29;Group 3,1.47± 0.12;p<0.001).Cardiac T2*was correlated with both cardiac triglycerides and left ventricular ejection fraction(LVEF)in overall participants(Groups le3)or Group 3(each p<0.001).Conclusionthe myocardial iron status of,patients with non-severe DHF,and patients with severe DHF were compared and it was found that myocardial iron deposition may exists in severe DHF.In addition,correlation analysis indicates that myocardial lipotoxicity may be responsible for this process.Based on previous research and the present results,iron deposition is likely a co-factor contributing to severe DHF.Therefore,this study provided a new direction for clinical therapy of DHF and made the foreshadowing for the profound pathogenesis study of DHF. |
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