Ultrafast spoiled gradient echo sequences
| Type of sequence | Philips | Siemens | GE | Hitachi | Toshiba |
| Ultrafast spoiled GE |
T1-TFE
THRIVE |
TurboFLASH
VIBE |
FGRE Fast SPGR FMPSPGR VIBRANT FAME LAVA | SARGE |
Fast FE
RADIANCE |
|
Ultrafast spoiled GE with magnetization preparation | IR-TFE | T1/T2-TurboFLASH |
IR-FSPGR DE-FSPGR | Fast FE |
Ultrafast gradient echo sequences use a small flip angle, a very short TR and optimized k-space filling to reduce acquisition time (to roughly one second per slice). The drawback of a small flip angle and very short TR is poor T1-weighting.
To preserve T1 contrast, a 180° inversion pulse prepares magnetization before repetitions of the ultrafast gradient echo imagery sequence . Effective inversion time will correspond to the delay between the inversion pulse and acquisition of the central k-space lines.
To obtain T2-weighting, the preparatory pattern is of the spin echo type (90° - 180°) so that the ultrafast GE imaging sequence can start with longitudinal magnetization whose amplitude depends on T2 .
K-space filling can follow variable trajectories (linear, centripetal, centrifugal) to determine image contrast. Either all the k-space lines are acquired after a single inversion pulse (« single shot »), or only a group of lines is acquired (segmented filling).
The speed of these T1-weighted gradient echo sequences is particularly suited to monitoring Gadolinium bolus arrival in imaging at arterial phase and in T1 high resolution 3D imaging.
Contents
MRI Sequences
- Introduction
- Characteristics
- Classification
- Acronyms
- Spin echo
- Fast spin echo
- Ultrafast spin echo
- Inversion Recovery / STIR / FLAIR
- Gradient echo
- Spoiled gradient echo
- Ultrafast spoiled gradient echo
- Steady-state gradient echo
- T2-enhanced steady-state gradient echo
- Balanced gradient echo
- Echo planar imaging (EPI)
- Hybrid echo (spin echo + gradient echo)
