Flip angle optimization for quantitative phase contrast MR imaging
β Scribed by Daniel B Ennis; Matthew J Middione
- Book ID
- 104499006
- Publisher
- BioMed Central
- Year
- 2011
- Tongue
- English
- Weight
- 375 KB
- Volume
- 13
- Category
- Article
- ISSN
- 1097-6647
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π SIMILAR VOLUMES
## Abstract The flip angle which maximizes contrast between materials with different __T__~1~can be caculatd from the root of a cubic expression. A simple closed form expression can be used if contrast is defined in a differential sense and results in only slight contrast loss even with large __T__
## Abstract In spoiled gradient echo sequences, the __T__~1~βweighting of image contrast is strongly affected by a nonlinear interaction of two sequence parameters, repetition time (TR) and flip angle (Ξ±). If Ξ± is not properly adjusted to compensate for variation in TR due to changing resolution, b
Theoretical expressions of flip angle values maximizing signal [a x -TE/2-b y -TE/2-echo-(TR-TE) -], [1] intensity and T 1 -dependent contrast are derived for spin-echo and inversion-recovery sequences. Experimental data and theoretical where a and b are respectively the nutating and refocusing pred