MR fingerprinting with simultaneous B1 estimation
Magnetic Resonance In Medicine
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Buonincontri, G., & Sawiak, S. (2015). MR fingerprinting with simultaneous B1 estimation. Magnetic Resonance In Medicine https://doi.org/10.1002/mrm.26009
Purpose MR fingerprinting (MRF) can be used for quantitative estimation of physical parameters in MRI. Here, we extend the method to incorporate B1 estimation. Methods The acquisition is based on steady state free precession MR fingerprinting with a Cartesian trajectory. To increase the sensitivity to the B1 profile, abrupt changes in flip angle were introduced in the sequence. Slice profile and B1 effects were included in the dictionary and the results from two- and three-dimensional (3D) acquisitions were compared. Acceleration was demonstrated using retrospective undersampling in the phase encode directions of 3D data exploiting redundancy between MRF frames at the edges of k-space. Results Without B1 estimation, T2 and B1 were inaccurate by more than 20%. Abrupt changes in flip angle improved B1 maps. T1 and T2 values obtained with the new MRF methods agree with classical spin echo measurements and are independent of the B1 field profile. When using view sharing reconstruction, results remained accurate (error <10%) when sampling under 10% of k-space from the 3D data. Conclusion The methods demonstrated here can successfully measure T1, T2, and B1. Errors due to slice profile can be substantially reduced by including its effect in the dictionary or acquiring data in 3D. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc.
MRF, fingerprinting, 3D, B1, T1, T2, relaxometry
G.B. was funded by INFN CNS 5.
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External DOI: https://doi.org/10.1002/mrm.26009
This record's URL: https://www.repository.cam.ac.uk/handle/1810/252988
Attribution-NonCommercial-NoDerivatives 4.0 International
Licence URL: http://creativecommons.org/licenses/by-nc-nd/4.0/