Increased left ventricular extracellular volume and enhanced twist function in type 1 diabetic individuals.

Individuals with type 1 diabetes (T1D) characteristically have high glycemic levels that over time can result in reactive fibrosis and abnormalities in myocardial function. T1 mapping with magnetic resonance imaging (MRI) can estimate the extent of reactive fibrosis by measurement of the extracellular volume fraction (ECV). The extent of alterations in the ECV and associated changes in left ventricular (LV) function and morphology in individuals with T1D is unknown. Fourteen individuals with long-term T1D and 14 sex-, age-, and body mass index-matched controls without diabetes underwent MRI measurement of myocardial T1 and ECV values as well as LV function and morphology. Ventricular mass, volumes, and global function (LVEF and circumferential/longitudinal/radial strain) were similar in those with T1D and controls. However, those with T1D had larger myocardial ECV (22.1 ± 1.8 vs. 20.1 ± 2.1, P = 0.008) and increased native (noncontrast) myocardial T1 values (1,211 ± 44 vs. 1,172 ± 43 ms, P < 0.001) as compared with controls. Both the ECV and native T1 values significantly correlated with several components of torsion and circumferential-longitudinal shear strain ( E cl , the shear strain component associated with twist). Individuals with T1D had increased systolic torsion ( P = 0.035), systolic torsion rate ( P = 0.032), peak E cl ( P = 0.001), and rates of change of systolic ( P = 0.007) and diastolic ( P = 0.007) E cl Individuals with T1D, with normal structure, LVEF, and strain, have increased extracellular volume and increased native T1 values with associated augmented torsion and E cl These measures may be useful in detecting the early stages of diabetic cardiomyopathy and warrant larger prospective studies. NEW & NOTEWORTHY Individuals with type 1 diabetes, with normal left ventricular structure and function (ejection fraction and strain), have signs of interstitial fibrosis, measured with MRI as increased extracellular volume fraction and increased native myocardial T1 , which significantly correlated with a number of measures of augmented left ventricular twist function. These measures may be useful in detecting the early stages of diabetic cardiomyopathy.