| 摘要 |
<p>A method and apparatus for determining the rate and direction of flow of a liquid in a selected region of a body by NMR techniques. NMR is excited preferentially in a slice of the body which includes the region and then a magnetic field having a gradient in a direction parallel to the flow of the liquid is applied, this field being effective to cause a phase difference between the resonance for the liquid which is flowing, or has flowed, in the region and the resonance for the rest of the slice. The free induction decay signal is measured, and the phase difference between the signal from the liquid, and the signal from the rest of the slice is related to the rate of flow of the liquid through the region.</p> |
