Fast echo-shifted gradient-recalled MRI: Combining a short repetition time with variable T2* weighting
✍ Scribed by Guoying Liu; Geoffrey Sobering; Alan W. Olson; Peter Van Gelderen; Chrit T. W. Moonen
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 901 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
The principles of a fast T~2~*‐sensitized MR imaging method (Moonen et al., Magn. Reson. Med. 26, 184 (1992)) are extended to further increase T~2~* sensitivity. It is shown that the period of T~2~*‐weighting can be lengthened by n TR‐periods by appropriate gradient schemes without RF refocusing resulting in progressively delayed gradient‐recalled echoes. This extension of the echo‐shifting concept thus introduces large flexibility in the choice of T~2~*‐weighting without changing total imaging time. The coherence pathway formalism is used to evaluate and describe the selection of the desired echo and the attenuation of unwanted coherences. The new techniques are demonstrated for tracking a bolus of susceptibility contrast agent in cat brain. Relative blood‐volume maps are derived with expected contrast between white and gray matter.