New Methods in Cardiac Magnetic Resonance Imaging and Spectroscopy

Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) are non-invasive techniques that provide fundamental information for tissue characterization in normal and diseased myocardium. Indeed, quantitative MRI gives insight into different pathophysiological conditions of myocardial tissue, like inflammation, edema and fibrosis, while MRS allows the quantification of crucial compounds involved in myocardial energy metabolism, such as triglycerides (TGs) and creatine (CR). The purpose of this thesis is to address several methodological challenges that have limited so far the application of these techniques in clinical settings, such as the low signal-to-noise ratio (SNR), the susceptibility to motion, the long scan times and the reproducibility of quantitative parameters. To achieve this purpose, the use of large coil arrays for SNR enhancement in cardiac MRS was investigated and advanced motion compensation strategies were implemented to increase the reproducibility of metabolite quantification. Moreover, in order to assess the regional distribution of myocardial TGs and CR in short scan times, a fast spectroscopic imaging technique was proposed and validated on healthy volunteers. Finally, a quantitative MRI method was implemented on a 3.0 Tesla MRI system for mapping T1 relaxation times in the human heart. The results achieved by the methods proposed in this thesis may facilitate the use of cardiac MRI and MRS in clinical routine for an accurate characterization of myocardial tissue.