Diffuse myocardial fibrosis in patient with diabetes mellitus type-II assessed by Cardiac Magnetic Resonance T1 mapping technique

Purpose: Diabetic cardiomyopathy (DCM) can be cause of a progressive dysfunction of ventricular contractility with the evolution to heart failure, independently of ischaemic heart disease or hypertension. Early stages of DCM are asymptomatic and characterized by various degrees of myocardial fibrosis. Our aim is to non-invasively detect myocardial fibrotic infiltration in DM-II patients, to assess its relationship with ventricular function abnormalities and to compared our results with a group of healthy controls. Methods and Materials: 100 patients affected by DM-II (57 man, 43 women) with preserved ventricular function and no history of ischaemic disease and 20 matching controls underwent contrast cardiac MR (CMR) between September 2014 and July 2017. Imaging protocol included: modified Look-Locker sequence before and 20 minutes after a double dose of 0.1 mmol/kg gadoterate meglumine injection; T2-mapping; ventricular function module; tagged-cineMR module and late gadolinium enhanced (LGE) imaging. Native myocardial T1 (nT1) and T2 values, extracellular volume fraction (ECV), ventricular torsion angle and myocardial strain values have been calculated and correlated to glycated haemoglobin (HbA1c) and duration of disease. Pearson Correlation, Mann-Whitney test and unpaired T-test were used for statistical analysis. Results: Patient group had higher nT1 and ECV values compared to controls (1018.29±73.28 ms vs.975±38 ms, 29.2±0.07% vs. 22.8±4.3% respectively, p<0.05 for both), whereas no significant differences occurred in T2 measurements (47.61±2.7ms vs. 47.0±2.8ms respectively, p=0.23). nT1 and ECV correlated with HbA1c (nT1: r2=0.99, p<0.0001; ECV: r2=0,07; p<0.005) and disease duration (nT1: r2=0.99, p<0.0001;ECV: r2=0,70 p<0,001) in DM-II patients. nT1 and ECV correlate positively torsion (nT1: r2=0.31, p<0.001; ECV: r2=0.30;p<0.001) and negatively with strain values in tagged-cineMR analysis (nT1 with global longitudinal and circunferential strain: both r2=-0.97, p<0.0001; ECV: r2=0.63 and r2=0.76, p<0.0001). LGE with ischemic pattern was found in eight patients as marker of silent infarction. Conclusion: In DM-II patients with preserved ventricular function, HbA1c values and disease duration showed a significant correlation to myocardial nT1 and ECV increase, as reflection of diffuse fibrosis, and geometrical modification.