Myocardial Effective Transverse Relaxation Time T 2∗ is Elevated in Hypertrophic Cardiomyopathy: A 7.0 T Magnetic Resonance Imaging Study

Abstract

Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the myocardium and bares the risk of progression to heart failure or sudden cardiac death. Identifying patients at risk remains an unmet need. Recognizing the dependence of microscopic susceptibility on tissue microstructure and on cardiac macromorphology we hypothesized that myocardial T2∗ might be altered in HCM patients compared to healthy controls. To test this hypothesis, myocardial T2∗-mapping was conducted at 7.0 Tesla to enhance T2∗-contrast. 2D CINE T2∗-mapping was performed in healthy controls and HCM patients. To ensure that T2∗ is not dominated by macroscopic magnetic field inhomogeneities, volume selective B0 shimming was applied. T2∗ changes in the interventricular septum across the cardiac cycle were analyzed together with left ventricular radius and ventricular septal wall thickness. The results show that myocardial T2∗ is elevated throughout the cardiac cycle in HCM patients compared to healthy controls. A mean septal T2∗ = 13.7 ± 1.1 ms (end-systole: T2∗,systole = 15.0 ± 2.1, end-diastole: T2∗,diastole = 13.4 ± 1.3 ms, T2∗,systole/T2∗,diastole ratio = 1.12) was observed in healthy controls. For HCM patients a mean septal T2∗ = 17.4 ± 1.4 ms (end-systole: T2∗,systole = 17.7 ± 1.2 ms, end-diastole: T2∗,diastole = 16.2 ± 2.5 ms, T2∗,systole/T2∗,diastole ratio = 1.09) was found. Our preliminary results provide encouragement that assessment of T2∗ and its changes across the cardiac cycle may benefit myocardial tissue characterization in HCM.