Cardiac MRI Functional Study. For each subject,localizing scans were obtained to define the long(2-chamber) axis of the left ventricle. A midventricular short-axis view was used to plan a 4-chamber view. The short-axis orientation was then deñned accurately, perpendicular to both the 2- and 4-chamber views. To cover the entire left ventricle, we acquired 10 contiguous (0-mm gap) short-axis slices in each study. The imaging sequence was a 2-dimensional, multiphase (16 cardiac phases acquired per cardiac cycle, resulting in a temporal resolution of 47 ms, for a heart rate of 80 beats per minute),steady-state free-precession sequence (TE, 1.5 ms;TR, 3.1 ms; flip angle, 70°; slice thickness, 8 mm;acquired in-plane spatial resolution, 1.8 x 2.0 mm) characterized by the application of balanced gradients in all directions.