Rotating frame spin lattice relaxation in a swine model of chronic, left ventricular myocardial infarction

T1ρ relaxation times were quantified in a swine model of chronic, left ventricular myocardial infarction. It was found that there were low frequency relaxation mechanisms that suppress endogenous contrast at low spin‐lock amplitudes and in T2‐weighted images. A moderate amplitude spin‐locking pulse could overcome these relaxation mechanisms. Relaxation dispersion data were measured over a range of RF field amplitudes, and a model was formulated to include dipole–dipole relaxation modulated by molecular rotation and an apparent exchange mechanism. These techniques may find some use in the clinic for the observation of chronic, left ventricular cardiac remodeling. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.