Slice profile and B corrections in 2D magnetic resonance fingerprinting.

Purpose: The goal of this study is to characterize and improve the accuracy of 2D magnetic resonance fingerprinting (MRF) scans in the presence of slice profile (SP) and B imperfections, which are two main factors that affect quantitative results in MRF.

Methods: The SP and B imperfections are characterized and corrected separately. The SP effect is corrected by simulating the radiofrequency pulse in the dictionary, and the B is corrected by acquiring a B map using the Bloch-Siegert method before each scan. The accuracy, precision, and repeatability of the proposed method are evaluated in phantom studies. The effects of both SP and B imperfections are also illustrated and corrected in the in vivo studies.

Results: The SP and B corrections improve the accuracy of the T and T values, independent of the shape of the radiofrequency pulse. The T and T values obtained from different excitation patterns become more consistent after corrections, which leads to an improvement of the robustness of the MRF design.

Conclusion: This study demonstrates that MRF is sensitive to both SP and B effects, and that corrections can be made to improve the accuracy of MRF with only a 2-s increase in acquisition time. Magn Reson Med 78:1781-1789, 2017. © 2017 International Society for Magnetic Resonance in Medicine.