Magnetic resonance fingerprinting using echo‐planar imaging: Joint quantification of T1 and T2∗ relaxation times

• Published in: Magnetic resonance in medicine Vol. 78; no. 5; pp. 1724 - 1733
• Main Authors: Rieger, Benedikt, Zimmer, Fabian, Zapp, Jascha, Weingärtner, Sebastian, Schad, Lothar R.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.11.2017
• Subjects: Accuracy; echo‐planar imaging; Fingerprinting; Image acquisition; Imaging; In vivo methods and tests; Magnetic resonance; magnetic resonance fingerprinting; Magnetic resonance imaging; relaxometry; T1; T2
• ISSN: 0740-3194; 1522-2594; 1522-2594
• DOI: 10.1002/mrm.26561

Purpose To develop an implementation of the magnetic resonance fingerprinting (MRF) paradigm for quantitative imaging using echo‐planar imaging (EPI) for simultaneous assessment of T1 and T2∗. Methods The proposed MRF method (MRF‐EPI) is based on the acquisition of 160 gradient‐spoiled EPI images with rapid, parallel‐imaging accelerated, Cartesian readout and a measurement time of 10 s per slice. Contrast variation is induced using an initial inversion pulse, and varying the flip angles, echo times, and repetition times throughout the sequence. Joint quantification of T1 and T2∗ is performed using dictionary matching with integrated B1+ correction. The quantification accuracy of the method was validated in phantom scans and in vivo in 6 healthy subjects. Results Joint T1 and T2∗ parameter maps acquired with MRF‐EPI in phantoms are in good agreement with reference measurements, showing deviations under 5% and 4% for T1 and T2∗, respectively. In vivo baseline images were visually free of artifacts. In vivo relaxation times are in good agreement with gold‐standard techniques (deviation T1: 4 ± 2%, T2∗: 4 ± 5%). The visual quality was comparable to the in vivo gold standard, despite substantially shortened scan times. Conclusion The proposed MRF‐EPI method provides fast and accurate T1 and T2∗ quantification. This approach offers a rapid supplement to the non‐Cartesian MRF portfolio, with potentially increased usability and robustness. Magn Reson Med 78:1724–1733, 2017. © 2016 International Society for Magnetic Resonance in Medicine.