| 摘要 |
A method of mapping the local distribution of the coupling constant J and for the application of this method, as for example, for examining the dynamic properties of an object. The object is excited with a first (90 DEG ) excitation pulse. A magnetic field gradient is applied to the object and after a first time delay, the object is subjected to a second (180 DEG ) excitation pulse. A magnetic field gradient is reapplied and after a second time delay, the spin echo signal is obtained. The sequence is repeated by changing the first and second delay times and changing the time integrals of the magnetic field gradients in accordance with the selected NMR imaging method. The second excitation pulse is preferably maintained at the midway point of the time between the first excitation pulse and the spin echo. The method may be used to analyze metabolic or physiological properties by using tracers with nuclei having coupling constants differing from the nuclei normally present in the object. |
