## Abstract Functional NMR imaging of the brains response to a simple visual task has been performed using a fast spin echo (FSE) imaging sequence at 1.5 T. The FSE method refocuses dephasing effects induced by large‐scale susceptibility variations, and permits imaging in regions where macroscopic
Sources of intensity nonuniformity in spin echo images at 1.5 T
✍ Scribed by Andrew Simmons; Paul S. Tofts; Gareth J. Barker; Simon R. Arridge
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 747 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0740-3194
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
This manuscript describes a number of sources of nonuniformity for spin echo images at 1.5 T. Both coil tuning and crosstalk can have significant effects on image nonuniformity. For short repetition times, nonuniformity increases with decreasing TR, possibly due to gradient eddy currents. In sections of RF coils with poor RF uniformity, image nonuniformity varies with both echo time and the number of echoes in a multiecho sequence. For the particular imager used, there are small differences between transverse and sagittal/coronal nonuniformity. The temporal stability of image nonuniformity is very good. The use of uniform oil phantoms is shown to be superior to low pass filtered images for correction of image nonuniformity.
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