| 摘要 |
A magnetic resonance excitation pulse (50, 150, 250) is applied to excite resonance in selected dipoles in an examination region. A second radio frequency pulse (60, 160, 260) induces a primary echo which is phase encoded by a phase encode gradient (56, 156, 256) with a first phase encode angle. Optionally, an additional phase encode gradient (356) may be applied after the primary echo to remove the first phase encoding. A third radio frequency pulse (70, 170, 270) rotates the magnetization, typically 90 DEG , to cause a stimulated echo (72, 172, 272) which is phase encoded in accordance with a second phase encode gradient (78, 178, 278). Optionally, another phase encode gradient pulse (378) may be applied after the stimulated echo to remove the second phase encoding. In the preferred embodiment, the first phase encoding is varied in steps from central phase encoding to a first preselected maximum phase encoding and the second phase encoding varies from about the central phase encoding to a second maximum of about the same magnitude as the first maximum but of the opposite polarity. In this manner, an interface between primary and secondary echo data is defined adjacent the central phase encode angle. The primary and stimulated echo data are corrected for discontinuities and reconstructed into an image representation. Redundant primary and stimulated echo data are collected adjacent the interface for comparison during the alignment.
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