| 摘要 |
<p>To derive NMR imaging information an object is subjected to a static magnetic field and a sinusoidally time-varying magnetic gradient field G. A 90° rf selective pulse P is applied around the time the gradient field G is zero and the subsequent free induction echoes E are detected and decoded. Additional non-selective pulses may be inserted at the times of echo peaks to refresh the echo signals. Additionally, to obtain two-dimensional information the gradient direction of the magnetic gradient field may be changed in successive cycles of the sinusoidal field.</p> |
