Abstract
The fast inversion recovery(fast IR)pulse sequence was evaluated. We compared the fast fluid attenuated invertion recovery(fast FLAIR)pulse sequence in which inversion time(TI)was established as equal to the water null point for the purpose of the water-suppressed T_i-weighted image, with the fast short TI inversion recovery(fast STIR)pulse sequence in which TI was established as eaual to the fat null point for purpose of fat suppression. In the fast FLAIR pulse sequence, the water null point was increased by making TR longer. In the FLAIR pulse sequence, the longitudinal magnetization contrast is determined by TI. If TI is increased, T_2-weighted contrast improves in the same way as inreasing TR for the SE pulse sequence, Therefore, images should be taken with long TR and long TI, which are longer than TR and longer than the water null point. On the other hand, the fat null point is ot affected by TR in the fast STIR pulse sequence, However, effective TE was affected by variation of the null point. This increased in proportion to the increase in effective TE. Our evaluation indicated that the fast STIR pulse sequence can control the extensive signals from fat in a short time.
