| 摘要 |
<p>A magnetic resonance method for in vivo measurement of water-suppressed localised proton spectra is proposed. Water suppression is achieved by means of a frequency selective adiabatic fast passage pulse. Subsequent to a waiting period after the adiabatic pulse, during which selectively excited water magnetisation has longitudinally relaxed until the longitudinal water magnetisation has reached an amplitude zero, an echo resonance signal in which water has been suppressed is generated by means of a volume-selective Hahn spin echo sequence. A spectrum is determined from the echo resonance signal by way of Fourier transformation. The method is particularly suitable for in vivo use in conjunction with surface coils where the rf electromagnetic field is liable to exhibit a substantial inhomogeneity. Comparatively small volumes can be measured by combination with a Hahn spin echo sequence, the overall examination time during in vivo measurement remaining within acceptable limits, for example during spectroscopic imaging.</p> |
