Yutaka Kato^{1}, Kazushige Ichikawa^{1}, Toshiaki Taoka^{2}, Hirokazu Kawaguchi^{3}, Katsutoshi Murata^{3}, Katsuya Maruyama^{3}, Gregor Koerzdoerfer^{4,5}, Josef Pfeuffer^{4}, Mathias Nittka^{4}, and Shinji Naganawa^{2}

This study focused on the stability of MRF in a phantom and
volunteers, and explored the feasibility of MRF with a shorter acquisition
time. Phantom scans on 40 days and volunteer scans on 5 days over 3 months showed
comparable repeatability and reproducibility of T1 and T2 values between MRF
with acquisition times of 41 sec and 20 sec. Shorter acquisition time has the
potential to expand the clinical usage of MRF.

Results

ISMRM/NIST system phantom: Figure 1 displays the T1 and T2 values and the temperature change among 40 days. There was no correlation between T1 or T2 value and the temperature. Figure 2 shows the 40-day CV; CVs were less than 0.7% for T1 values and less than 2.9% for T2 values. The 40-day variation between long and short MRF measurements of T1 and T2 is displayed in Figure 3. The mean bias for T1 was 0.4%, and the 95% limits of agreement ranged from -1.9% to 2.7%. The mean bias for T2 was 2.5%, and the 95% limits of agreement ranged from -6.0% to 1.0%. One data point with the shortest T2 value was outside of the limits of agreement.

Human Volunteers: Figure 4 shows the 5-day CV; CVs were less than 2.3% for T1 values and less than 5.1% for T2 values. The 5-day variation between long and short MRF measurements of T1 and T2 is displayed in Figure 5. The mean bias for T1 was -1.2%, and the 95% limits of agreement ranged from -4.6% to 2.3%. The mean bias for T2 was 4.9%, and the 95% limits of agreement ranged from -2.5% to 12.3%.

Conclusion

- Russek SE, Boss M, Jackson EF, Jennings DL, Evelhoch JL, Gunter JL, Sorensen AG. Characterization of NIST/ISMRM MRI system phantom. In Proceedings of the 20th Annual Meeting of ISMRM, Melbourne, Victoria, Austraia, 2012. Abstract 2456
- Jiang Y, Ma D, Seiberlich N, Gulani V, Griswold MA. MR fingerprinting using fast imaging with steady state precession (FISP) with spiral readout. Magn. Reson. Med. 2015;74:spcone-spcone. doi: 10.1002/mrm.26048.
- Pfeuffer J, Kechagias A, Meyer CH, Körzdörfer G, Nittka M. Mitigation of Spiral Undersampling Artifacts in Magnetic Resonance Fingerprinting (MRF) by Adapted Interleave Reordering. In Proceedings of the 25th Annual Meeting of ISMRM, 2017. Abstract 0133
- Chung S, Kim D, Breton E, Axel L. Rapid B1+ mapping using a preconditioning RF pulse with turboFLASH readout. Magn. Reson. Med. 2010;64:439–446. doi: 10.1002/mrm.22423.

Fig. 1. T1 and T2 values of
each sphere phantom over 40 days. (a) Long
MRF, (b) Short
MRF

Fig. 2. Coefficient of variation of
(a) T1 and (b) T2 values among 40 days in
the ISMRM/NIST system phantom.

Fig. 3. Bland-Altman plots showing
validation between long and short MRF for (a) T1 and (b) T2 values averaged
over 40 days in the ISMRM/NIST phantom.

Fig. 4. Coefficient of variation of (a)
T1 and (b) T2 values among 5 days in
two human volunteers A and B.

Fig. 5. Bland-Altman plots showing
validation between long and short MRF for (a)
T1 and (b) T2 values averaged over 5 days in two human volunteers.