FIGURE 1.
A, Pulse sequences showing the phase-encoded (top) and Hadamard slice-encoded (bottom) acquisitions. Because the Hadamard encoding is performed with cascaded slice excitations with RF phase encoding (two slices at 0°, 0° and 0°, 180°), the echo times for each slice are slightly different, 40 ms and 45 ms. B, The typical longitudinal coverage of the 3D and Hadamard acquisitions is shown. C, The effect of targeted shimming is shown in the table (mean and standard deviation): using a restricted (21 mm) or large (48 mm) shim region, with a significant improvement in MTL field homogeneity (σB0) with the smaller shim region