| Background and Purpose:Diabetes is one of the most common chronic diseases in the world.At present,the prevalence of diabetes in the world exceeds 10%,of which more than 90% are Type 2 Diabetes Mellitus(T2DM).The risk of cardiovascular disease in diabetic patients is higher than that in normal people.About two-thirds of T2 DM patients eventually die of cardiovascular complications,which is the leading cause of death for patients with diabetes.Some studies have shown that metabolic disorders of T2 DM can lead to heart problems,partly due to increased visceral fat deposition,especially increased pericardial fat deposition,and often accompanied by glucose metabolism disorders.Pericardial adipose tissue is the metabolically active visceral adipose tissue deposited around the heart,which is anatomically distributed around the myocardium and coronary artery,and there is no fascial separation between them.It can secrete related factors through paracrine or vascular secretion pathways.Local interaction with the myocardium is closely related to the development of cardiovascular disease,including coronary heart disease.Among them,the increase in pericardial fat deposition may be related to early cardiac dysfunction in T2 DM.Therefore,accurately assessing the extent of pericardial fat deposition in T2 DM is extremely important for disease monitoring and early intervention.Cardiovascular magnetic resonance(CMR)has been widely used to evaluate cardiac structure,function and tissue characteristics because of its good reproducibility,multi-parameter imaging and no ionizing radiation.The myocardial strain and strain rate obtained by tissue tracking technique based on CMR are sensitive indicators of early changes in myocardial motor function,which can be used to detect myocardial motor dysfunction in patients with T2 DM.Pericardial fat can be clearly displayed on CMR cine images,and the degree of pericardial fat deposition can be quantitatively assessed.At present,there are few magnetic resonance imaging studies on pericardial fat deposition and myocardial function changes in T2 DM patients.The effect of pericardial fat deposition on myocardial function in patients with T2 DM is unclear,and whether there is a correlation between the two is unknown.In this study,CMR cine and tissue tracking technology were used to comprehensively evaluate the changes of left ventricular myocardial function and the degree of pericardial fat deposition in T2 DM patients,and to study the correlation between changes in myocardial function of T2 DM and the degree of pericardial fat deposition in order to find sensitive biological indicators of early cardiac dysfunction in T2 DM.Objective:1、Whether left ventricular myocardial function has changed in T2 DM patients;2、Whether T2 DM patients have pericardial fat deposition;3、Whether the changes of left ventricular myocardial function in T2 DM patients arecorrelated with pericardial fat deposition.Materials and Methods:T2DM patients who were admitted to our hospital from June 2015 to March 2018 were enrolled,according to inclusion and exclusion criteria,eventually included 48 patients with T2 DM,including 27 males and 21 females;in addition,32 healthy volunteers matched by age and sex were selected as the control group,including 14 males and 18 females.The ethics committee of the hospital approved this research and all the subjects signed the informed consent.All subjects underwent MRI examination,fasting blood was drawn before MRI examination and sent to laboratory and nuclear medicine departments to determine the corresponding blood biochemical indicators.The left ventricular myocardial strain was quantitatively analyzed by CMR-TT technique,and the parameters of myocardial strain and strain rate were obtained.The repeatability of myocardial strain analysis was tested to verify the consistency between the intra-observer and the inter-observer.The pericardial fat thickness was measured vertically at the apex of the left ventricle on the horizontal four-chamber cardiac cine image,and the pericardial fat deposition was assessed by the fat thickness.Pearson correlation analysis was used to analyze the correlation between pericardial fat thickness and left ventricular myocardial strain and strain rate.Results:Compared with the control subjects,the triglyceride,serum glucose and glycated hemoglobin in the T2 DM group were significantly increased,and the difference was statistically significant(P<0.05);compared with the control group,the low density lipoprotein and high density lipoprotein in the T2 DM group were all decreased,and the difference was statistically significant(P<0.05);the other blood biochemical indicators were not significantly different between the two groups(P>0.05).There was no significant difference in cardiac function parameters such as ejection fraction between T2 DM group and control group(P > 0.05).The circumferential peak diastolic strain rate and longitudinal peak diastolic strain rate in the T2 DM group were significantly lower than those in the control group(P < 0.05).The circumferential peak systolic strain rate and the longitudinal peak systolic strain rate are generally repeatable between inter-observers and intra--observers(ICC < 0.75),(ICC<0.75);The other strains and strain rates have good repeatability(ICC > 0.75).Compared with the control group,the thickness of pericardial fat and paracardial fat in the T2 DM group increased significantly(P <0.05).There was no significant difference in epicardial fat thickness between the two groups(P > 0.05).The correlation analysis showed that the circumferential peak diastolic strain rate was negatively correlated with pericardial fat thickness and paracardial fat thickness(r values were-0.335,-0.316,P < 0.05);The longitudinal peak diastolic strain rate was negatively correlated with pericardial fat thickness and paracardial fat thickness(r values were-0.269,-0.230,P < 0.05).Conclusion:1、 The circumferential peak diastolic strain rate and longitudinal peak diastolic strain rate decreased in the patients with T2 DM,while cardiac function parameters remained normal,indicating that subclinical diastolic dysfunction had occurred in the patients with T2 DM.2、 Pericardial fat thickness and paracardial fat thickness increased in patients with T2 DM and patients with T2 DM are more likely to have pericardial fat deposition than normal people.3、 The subclinical diastolic dysfunction of the heart in T2 DM patients may be related to the increase in pericardial fat deposition. |
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