| 摘要 |
A method for rapid acquisition of NMR data utilizes excitation pulses which rotate the longitudinal magnetization through an angle smaller than 90 DEG to create a relatively large transverse magnetization component. A first 180 DEG RF pulse is then applied to create a spin-echo signal, while a second 180 DEG RF pulse is used to rapidly return to equilibrium the residual longitudinal magnetization inverted by the first pulse. The combination of the excitation and the second 180 DEG pulses permits the sequence repetition time to be shortened, thereby reducing the total data collection time. The method is applicable to, for example, two- and three-dimensional embodiments of Fourier transform and multiple-angle projection reconstruction NMR imaging methods.
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