Magnetic resonance fingerprinting (MRF) is a promising method for fast simultaneous quantification of multiple tissue parameters. The objective of this study is to improve the coverage of MRF based on echo-planar imaging (MRF-EPI) by using a slice-interleaved acquisition scheme. For this, the MRF-EPI is modified to acquire several slices in a randomized interleaved manner, increasing the effective repetition time of the spoiled gradient echo readout acquisition in each slice. Per-slice matching of the signal-trace to a precomputed dictionary allows the generation of T1 and T2∗ maps with integrated B1 + correction. Subsequent compensation for the coil sensitivity profile and normalization to the cerebrospinal fluid additionally allows for quantitative proton density (PD) mapping. Numerical simulations are performed to optimize the number of interleaved slices. Quantification accuracy is validated in phantom scans and feasibility is demonstrated in-vivo. Numerical simulations suggest the acquisition of four slices as a trade-off between quantification precision and scan-time. Phantom results indicate good agreement with reference measurements (Difference T1: -2.4 ± 1.1%, T2∗: -0.5 ± 2.5%, PD: -0.5 ± 7.2%). In-vivo whole-brain coverage of T1, T2∗ and PD with 32 slices was acquired within 3:36 minutes, resulting in parameter maps of high visual quality and comparable performance with single-slice MRF-EPI at 4-fold scan-time reduction.
Bibliographical noteFunding Information:
NIH; Grant numbers: R00HL111410, NSF; Grant number: CCF-1651825. Partially funded by a Proyecto de Investigacion en Salud PI15/00587, S.L., A.S., integrated in the Plan Estatal I+D+I and co-funded by ISCIII-Subdirección General de Evaluación and European Regional Development Fund (ERDF). Red Española de Esclerosis Múltiple (REEM) (RD16/0015/0002, RD16/0015/0003, RD12/0032/0002, RD12/0060/01-02). S.L. is recipient of a Juan Rodes grant from the Instituto de Salud Carlos III (JR14/00015). We acknowledge the financial support of the Deutsche Forschungsgemeinschaft and Ruprecht-Karls-Universität Heidelberg within the funding programme Open Access Publishing.