Myocardial effective transverse relaxation time T 2 * Correlates with left ventricular wall thickness: A 7.0 T MRI study

Purpose Myocardial effective relaxation timeT 2 *is commonly regarded as a surrogate for myocardial tissue oxygenation. However, it is legitimate to assume that there are multiple factors that influenceT 2 *. To this end, this study investigates the relationship betweenT 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 CINET 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, andT 2 *were analyzed. Macroscopic magnetic field changes were elucidated using cardiac phase–resolved magnetic field maps. Results Ventricular septalT 2 *changes periodically over the cardiac cycle, increasing in systole and decreasing in diastole. Ventricular septal wall thickness andT 2 *showed a significant positive correlation, whereas the inner LV radius andT 2 *were negatively correlated. The effect of macroscopic magnetic field gradients onT 2 *can be considered minor in the ventricular septum. Conclusion Our findings suggest that myocardialT 2 *is related to tissue blood volume fraction. Temporally resolvedT 2 *mapping could be beneficial for myocardial tissue characterization and for understanding cardiac (patho)physiology in vivo. Magn Reson Med 77:2381–2389, 2017. © 2016 International Society for Magnetic Resonance in Medicine