Myocardial effective transverse relaxation time T2* Correlates with left ventricular wall thickness: A 7.0 T MRI study.

Purpose: Myocardial effective relaxation time T-2 is commonly regarded as a surrogate for myocardial tissue oxygenation. However, it is legitimate to assume that there are multiple factors that influence T-2. To this end, this study investigates the relationship between T-2 and cardiac macromorphology given by left ventricular (LV) wall thickness and left ventricular radius, and provides interpretation of the results in the physiological context. Methods: High spatio-temporally resolved myocardial CINE T-2 mapping was performed in 10 healthy volunteers using a 7.0 Tesla (T) full-body MRI system. Ventricular septal wall thickness, left ventricular inner radius, and T-2 were analyzed. Macroscopic magnetic field changes were elucidated using cardiac phase-resolved magnetic field maps. Results: Ventricular septal T-2 changes periodically over the cardiac cycle, increasing in systole and decreasing in diastole. Ventricular septal wall thickness and T-2 showed a significant positive correlation, whereas the inner LV radius and T-2 were negatively correlated. The effect of macroscopic magnetic field gradients on T-2 can be considered minor in the ventricular septum. Conclusion: Our findings suggest that myocardial T-2 is related to tissue blood volume fraction. Temporally resolved T-2 mapping could be beneficial for myocardial tissue characterization and for understanding cardiac (patho) physiology in vivo. (C) 2016 International Society for Magnetic Resonance in Medicine