Assessment of Diabetic Cardiomyopathy by Cardiovascular Magnetic Resonance T1 Mapping: Correlation with Left-Ventricular Diastolic Dysfunction and Diabetic Duration

Purpose. To quantify extracellular matrix expansion with the cardiovascular magnetic resonance (CMR) T1 mapping technique and the derived extracellular volume fraction (ECV) in diabetic cardiomyopathy (DbCM) patients and to detect the relationship among ECV, duration of diabetes, and diastolic function. Materials. Thirty-eight patients with diabetic cardiomyopathy (20 males, age 54.6 ± 8.6 years) and thirty-two matched normal controls (15 males, age 51.4 ± 13.6 years) were prospectively enrolled. All of them were scanned by T1 mapping to obtain the native and postcontrast T1 values of myocardium and blood, and ECV was calculated accordingly. All patients also underwent transthoracic echocardiographic tissue Doppler imaging to assess left-ventricular diastolic function. Results. There was a significant difference in ECV between the two groups (DbCMs 30.4 ± 2.9% versus controls 27.1 ± 2.4%, P<0.001). The duration of diabetes was positively and strongly associated with ECV (R=0.539, P=0.0005). There was also a significant difference in ECV (P≤0.001) among four groups (A, controls; B, DbCM patients with duration of diabetes <5 years; C, 5–10 years; and D, >10 years). ECV was negatively associated with LV E’/A’ (R=−0.403, P=0.012). Conclusion. CMR T1 mapping can reflect myocardial extracellular matrix expansion in DbCM and can be a powerful technique for the early diagnosis of DbCM.

Abstract 19370: Myocardial Extracellular Volume is Elevated in Human Duchenne Muscular Dystrophy

Introduction: Duchenne muscular dystrophy (DMD) leads to cardiomyopathy (CM) with variable severity and age of onset. Predicting early CM would alter therapeutic approaches and improve morbidity and mortality. Extracellular volume (ECV) calculated with cardiac MRI (CMR) quantifies extracellular matrix expansion, including myocardial fibrosis, and has never been reported in human DMD. We hypothesized that subjects with DMD would have abnormal ECV and that these values would correlate with other markers of LV function. Methods: 27 DMD subjects were prospectively studied. CMR included LVEF, late gadolinium enhancement (LGE), circumferential strain (ε cc ), and modified Look-Locker (MOLLI) sequences to calculate ECV maps (in-house software using Matlab). ECV calculated for each segment in the short axis at mid-ventricle and compared with LVEF and ε cc using linear regression. Normal values taken from unmatched cohort of healthy male adults with mean ECV of 0.25 ± 0.015 (range 0.23-0.28). Results: Imaging was adequate to calculate ECV maps in 20 DMD subjects. Mean age in years was 14. Mean LVEF was 52% and mean global ε cc was -14.6%; 11 subjects had LVEF < 55% and 6 had negative LGE. Mean ECV was 0.33 ± 0.05 (0.25-0.45); there was significant intersubject and intersegment variability (Figure 1). When compared with highest mean control ECV (0.28), only one subject had a normal ECV in every segment. In subjects with LVEF ≥ 55%, the mean ECV was 0.32 ± 0.07 (0.25-0.45). In subjects with negative LGE, the mean ECV was 0.28 ± 0.04 (0.25-0.36). The ECV of the inferolateral and anterolateral segments correlated with LVEF (p=0.025 and p<0.001) and the inferolateral ECV correlated with mean ε cc (p=0.025). Conclusions: In this cohort, 19/20 DMD subjects have elevated segmental ECV, even with normal LVEF and negative LGE. Segmental ECV correlates with both LVEF and mean ε cc . ECV may be a more subtle biomarker of early myocardial disease than standard measures such as LVEF and LGE in human DMD.